Merge branch 'master' into foodApiDocker

2026-06-22 20:00:40 +00:00 · 2023-06-28 14:18:33 +03:00
parent 93641feb8d c74d3b2d1a
commit 5ec5864a74
101 changed files with 14015 additions and 0 deletions
@@ -82,6 +82,7 @@ celerybeat-schedule
 *.sage.py

 # Environments
+*.env
 .env
 .venv
 env/
@@ -0,0 +1,6 @@
+FROM python:3.7-slim
+LABEL maintainer="Rodney Osodo"
+WORKDIR /app
+COPY requirements.txt .
+RUN pip3 install --no-cache-dir -r requirements.txt
+COPY app.py .
@@ -0,0 +1,24 @@
+import requests
+
+values = """
+  {
+    "command": "cancel",
+    "data": {
+      "api_key": "aOYE0BD3rz03QKPXUx4R",
+      "api_username": "qualis",
+      "order_no": "AN82TT944-33W"
+    },
+    "request_token_id": "request_token_id"
+  }
+"""
+
+headers = {
+  'Content-Type': 'application/json'
+}
+
+url = 'https://apitest.sendyit.com/v1/#cancel'
+
+request = requests.post(url, data=values, headers=headers)
+
+response_body = request.text
+print(response_body)
@@ -0,0 +1,74 @@
+import requests
+
+values = """
+  {
+    "command": "request",
+    "data": {
+      "api_key": "aOYE0BD3rz03QKPXUx4R",
+      "api_username": "qualis",
+      "vendor_type": 1,
+      "rider_phone": "0728561783",
+      "from": {
+        "from_name": "Green House",
+        "from_lat": -1.300577,
+        "from_long": 36.78183,
+        "from_description": ""
+      },
+      "to": {
+        "to_name": "KICC",
+        "to_lat": -1.28869,
+        "to_long": 36.823363,
+        "to_description": ""
+      },
+      "recepient": {
+        "recepient_name": "Sender Name",
+        "recepient_phone": "0709779779",
+        "recepient_email": "sendyer@gmail.com",
+        "recepient_notes": "recepient specific Notes"
+      },
+      "sender": {
+        "sender_name": "Sendyer Name",
+        "sender_phone": "0709 779 779",
+        "sender_email": "sendyer@gmail.com",
+        "sender_notes": "Sender specific notes"
+      },
+      "delivery_details": {
+        "pick_up_date": "2016-04-20 12:12:12",
+        "collect_payment": {
+          "status": false,
+          "pay_method": 0,
+          "amount": 10
+        },
+        "return": true,
+        "note": " Sample note",
+        "note_status": true,
+        "request_type": "delivery",
+        "order_type": "ondemand_delivery",
+        "ecommerce_order": false,
+        "express": false,
+        "skew": 1,
+        "package_size": [
+          {
+            "weight": 20,
+            "height": 10,
+            "width": 200,
+            "length": 30,
+            "item_name": "laptop"
+          }
+        ]
+      }
+    },
+    "request_token_id": "request_token_id"
+  }
+"""
+
+headers = {
+  'Content-Type': 'application/json'
+}
+url = "https://apitest.sendyit.com/v1/##request"
+
+request = requests.post(url, data=values, headers=headers)
+
+response_body = request.text
+
+print(response_body)
@@ -0,0 +1,24 @@
+import requests
+
+values = """
+  {
+    "command": "track",
+    "data": {
+      "api_key": "aOYE0BD3rz03QKPXUx4R",
+      "api_username": "qualis",
+      "order_no": "AN82G6946-4SA"
+    },
+    "request_token_id": "request_token_id"
+  }
+"""
+
+headers = {
+  'Content-Type': 'application/json'
+}
+
+url = "https://apitest.sendyit.com/v1/#track"
+
+request = requests.post(url, data=values, headers=headers)
+
+response_body = request.text
+print(response_body)
@@ -0,0 +1,54 @@
+from flask import Flask, request, jsonify
+import requests, json, os
+from dotenv import load_dotenv
+
+load_dotenv("secrets.env")
+
+api_key = os.environ.get("api_key")
+api_username = os.environ.get("api_username")
+app = Flask(__name__)
+
+def make_request(data, url):
+    data['data']['api_key'] = api_key
+    data['data']['api_username'] = api_username
+    headers = {
+    'Content-Type': 'application/json'
+    }
+    request = requests.post(url, data=json.dumps(data), headers=headers)
+    response_body = request.json()
+    return response_body
+
+@app.route('/')
+def hello():
+    return "Base url"
+
+
+@app.route('/requestdelivery', methods=['POST'])
+def request_delivery():
+    delivery_data = request.get_json()
+    url = "https://apitest.sendyit.com/v1/##request"
+    response = make_request(delivery_data, url)
+    return response
+
+
+@app.route('/canceldelivery', methods=['POST'])
+def cancel_delivery():
+    delivery_data = request.get_json()
+    url = 'https://apitest.sendyit.com/v1/#cancel'
+    response = make_request(delivery_data, url)
+    return response
+
+@app.route('/trackdelivery', methods=['POST'])
+def track_delivery():
+    delivery_data = request.get_json()
+    url = "https://apitest.sendyit.com/v1/#track"
+    response = make_request(delivery_data, url)
+    return response
+
+
+if __name__ == '__main__':
+    app.run(host="0.0.0.0", port=5000)
+
+
+# curl  --header "Content-Type: application/json" --request POST  --data '{"command": "cancel","data": {"api_key": "aOYE0BD3rz03QKPXUx4R","api_username": "qualis","order_no": "AN82TT944-33W"},"request_token_id": "request_token_id"}'  http://localhost:5000/canceldelivery
+
@@ -0,0 +1,12 @@
+certifi==2019.11.28
+chardet==3.0.4
+click==7.1.1
+Flask==1.1.1
+idna==2.9
+itsdangerous==1.1.0
+Jinja2==2.11.1
+MarkupSafe==1.1.1
+python-dotenv==0.12.0
+requests==2.23.0
+urllib3==1.25.8
+Werkzeug==1.0.0
@@ -0,0 +1,65 @@
+{
+	"ImportPath": "userService2",
+	"GoVersion": "go1.13",
+	"GodepVersion": "v80",
+	"Deps": [
+		{
+			"ImportPath": "github.com/dgrijalva/jwt-go",
+			"Comment": "v3.2.0-20-gdc14462",
+			"Rev": "dc14462fd58732591c7fa58cc8496d6824316a82"
+		},
+		{
+			"ImportPath": "github.com/gorilla/mux",
+			"Comment": "v1.7.4",
+			"Rev": "75dcda0896e109a2a22c9315bca3bb21b87b2ba5"
+		},
+		{
+			"ImportPath": "github.com/jinzhu/gorm",
+			"Comment": "v1.9.12-3-g7ea143b",
+			"Rev": "7ea143b5484fe28148d5c73cfd43b26e8a89c94e"
+		},
+		{
+			"ImportPath": "github.com/jinzhu/gorm/dialects/postgres",
+			"Comment": "v1.9.12-3-g7ea143b",
+			"Rev": "7ea143b5484fe28148d5c73cfd43b26e8a89c94e"
+		},
+		{
+			"ImportPath": "github.com/jinzhu/inflection",
+			"Comment": "v1.0.0-2-g196e6ce",
+			"Rev": "196e6ce06ca4513fbcfcbc35dc15f66074df47c9"
+		},
+		{
+			"ImportPath": "github.com/joho/godotenv",
+			"Comment": "v1.3.0-14-gd6ee687",
+			"Rev": "d6ee6871f21dd95e76563a90f522ce9fe75443f8"
+		},
+		{
+			"ImportPath": "github.com/lib/pq",
+			"Comment": "v1.3.0-4-g9eb3fc8",
+			"Rev": "9eb3fc897d6fd97dd4aad3d0404b54e2f7cc56be"
+		},
+		{
+			"ImportPath": "github.com/lib/pq/hstore",
+			"Comment": "v1.3.0-4-g9eb3fc8",
+			"Rev": "9eb3fc897d6fd97dd4aad3d0404b54e2f7cc56be"
+		},
+		{
+			"ImportPath": "github.com/lib/pq/oid",
+			"Comment": "v1.3.0-4-g9eb3fc8",
+			"Rev": "9eb3fc897d6fd97dd4aad3d0404b54e2f7cc56be"
+		},
+		{
+			"ImportPath": "github.com/lib/pq/scram",
+			"Comment": "v1.3.0-4-g9eb3fc8",
+			"Rev": "9eb3fc897d6fd97dd4aad3d0404b54e2f7cc56be"
+		},
+		{
+			"ImportPath": "golang.org/x/crypto/bcrypt",
+			"Rev": "78000ba7a073cafc0278790f6bce552a0f25850e"
+		},
+		{
+			"ImportPath": "golang.org/x/crypto/blowfish",
+			"Rev": "78000ba7a073cafc0278790f6bce552a0f25850e"
+		}
+	]
+}
@@ -0,0 +1,5 @@
+This directory tree is generated automatically by godep.
+
+Please do not edit.
+
+See https://github.com/tools/godep for more information.
@@ -0,0 +1,54 @@
+# uber4freefood
+## Users Api
+###### Postgres set up
+Edit the file in `/models/base.go` on line `28` to set local password and user before running.
+###### Running
+Run `go run main.go`
+###### Api Routes
+`:*port/api/user/login`
+method `post`
+body `json`
+`{"email": "", "password": ""}`
+
+`:*port/api/user/login`
+method `post`
+body `json`
+`{"email": "", "firstname": "", "lastname": "", "phonenumber": "", "usertype": "", "profilepicname": "","password": ""}`
+
+###### Response
+body 
+```
+{
+    "account": {
+        "ID": ,
+        "CreatedAt": "",
+        "UpdatedAt": "",
+        "DeletedAt": ,
+        "email": "",
+        "firstname": "",
+        "lastname": "",
+        "phonenumber": "",
+        "usertype": "",
+        "profilepicname": "",
+        "password": "",
+        "token": ""
+    },
+    "message": "",
+    "status": 
+}
+```
+###### Token
+Type : `JWT`
+
+key: in `.env` file
+
+body:
+```
+{
+ alg: "HS256",
+ typ: "JWT"
+}.
+{
+ UserId: 
+}.
+```
@@ -0,0 +1,79 @@
+package app
+
+import (
+	"context"
+	"fmt"
+	"github.com/dgrijalva/jwt-go"
+	"userService2/models"
+	u "userService2/utils"
+	"net/http"
+	"os"
+	"strings"
+)
+
+var JwtAuthentication = func(next http.Handler) http.Handler {
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+
+		notAuth := []string{"/api/user/new", "/api/user/login"} //List of endpoints that doesn't require auth
+		requestPath := r.URL.Path                               //current request path
+
+		//check if request does not need authentication, serve the request if it doesn't need it
+		for _, value := range notAuth {
+
+			if value == requestPath {
+				next.ServeHTTP(w, r)
+				return
+			}
+		}
+
+		response := make(map[string]interface{})
+		tokenHeader := r.Header.Get("Authorization") //Grab the token from the header
+
+		if tokenHeader == "" { //Token is missing, returns with error code 403 Unauthorized
+			response = u.Message(false, "Missing auth token")
+			w.WriteHeader(http.StatusForbidden)
+			w.Header().Add("Content-Type", "application/json")
+			u.Respond(w, response)
+			return
+		}
+
+		splitted := strings.Split(tokenHeader, " ") //The token normally comes in format `Bearer {token-body}`, we check if the retrieved token matched this requirement
+		if len(splitted) != 2 {
+			response = u.Message(false, "Invalid/Malformed auth token")
+			w.WriteHeader(http.StatusForbidden)
+			w.Header().Add("Content-Type", "application/json")
+			u.Respond(w, response)
+			return
+		}
+
+		tokenPart := splitted[1] //Grab the token part, what we are truly interested in
+		tk := &models.Token{}
+
+		token, err := jwt.ParseWithClaims(tokenPart, tk, func(token *jwt.Token) (interface{}, error) {
+			return []byte(os.Getenv("token_password")), nil
+		})
+
+		if err != nil { //Malformed token, returns with http code 403 as usual
+			response = u.Message(false, "Malformed authentication token")
+			w.WriteHeader(http.StatusForbidden)
+			w.Header().Add("Content-Type", "application/json")
+			u.Respond(w, response)
+			return
+		}
+
+		if !token.Valid { //Token is invalid, maybe not signed on this server
+			response = u.Message(false, "Token is not valid.")
+			w.WriteHeader(http.StatusForbidden)
+			w.Header().Add("Content-Type", "application/json")
+			u.Respond(w, response)
+			return
+		}
+
+		//Everything went well, proceed with the request and set the caller to the user retrieved from the parsed token
+		fmt.Sprintf("User %", tk.UserId) //Useful for monitoring
+		ctx := context.WithValue(r.Context(), "user", tk.UserId)
+		r = r.WithContext(ctx)
+		next.ServeHTTP(w, r) //proceed in the middleware chain!
+	});
+}
@@ -0,0 +1,15 @@
+package app
+
+import (
+	u "userService2/utils"
+	"net/http"
+)
+
+var NotFoundHandler = func(next http.Handler) http.Handler {
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotFound)
+		u.Respond(w, u.Message(false, "This resources was not found on our server"))
+		next.ServeHTTP(w, r)
+	})
+}
@@ -0,0 +1,34 @@
+package controllers
+
+import (
+	"encoding/json"
+	"userService2/models"
+	u "userService2/utils"
+	"net/http"
+)
+
+var CreateAccount = func(w http.ResponseWriter, r *http.Request) {
+
+	account := &models.Account{}
+	err := json.NewDecoder(r.Body).Decode(account) //decode the request body into struct and failed if any error occur
+	if err != nil {
+		u.Respond(w, u.Message(false, "Invalid request"))
+		return
+	}
+
+	resp := account.Create() //Create account
+	u.Respond(w, resp)
+}
+
+var Authenticate = func(w http.ResponseWriter, r *http.Request) {
+
+	account := &models.Account{}
+	err := json.NewDecoder(r.Body).Decode(account) //decode the request body into struct and failed if any error occur
+	if err != nil {
+		u.Respond(w, u.Message(false, "Invalid request"))
+		return
+	}
+
+	resp := models.Login(account.Email, account.Password)
+	u.Respond(w, resp)
+}
@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+	"github.com/gorilla/mux"
+	"userService2/app"
+	"userService2/controllers"
+	"net/http"
+	"os"
+)
+
+func main() {
+
+	router := mux.NewRouter()
+
+	router.HandleFunc("/api/user/new", controllers.CreateAccount).Methods("POST")
+	router.HandleFunc("/api/user/login", controllers.Authenticate).Methods("POST")
+
+	router.Use(app.JwtAuthentication) //attach JWT auth middleware
+
+	//router.NotFoundHandler = app.NotFoundHandler
+
+	port := os.Getenv("PORT")
+	if port == "" {
+		port = "8000" //localhost
+	}
+
+	fmt.Println(port)
+
+	err := http.ListenAndServe(":"+port, router) //Launch the app, visit localhost:8000/api
+	if err != nil {
+		fmt.Print(err)
+	}
+}
@@ -0,0 +1,127 @@
+package models
+
+import (
+	"os"
+	"strings"
+	u "userService2/utils"
+
+	"github.com/dgrijalva/jwt-go"
+	"github.com/jinzhu/gorm"
+	"golang.org/x/crypto/bcrypt"
+)
+
+/*
+JWT claims struct
+*/
+type Token struct {
+	UserId uint
+	jwt.StandardClaims
+}
+
+//a struct to rep user account
+type Account struct {
+	gorm.Model
+	Email          string `json:"email"`
+	FirstName      string `json:"firstname"`
+	LastName       string `json:"lastname"`
+	Phonenumber    string `json:"phonenumber"`
+	Usertype       string `json:"usertype"`
+	ProfilePicName string `json:"profilepicname"`
+	Password       string `json:"password"`
+	Token          string `json:"token";sql:"-"`
+}
+
+//Validate incoming user details...
+func (account *Account) Validate() (map[string]interface{}, bool) {
+
+	if !strings.Contains(account.Email, "@") {
+		return u.Message(false, "Email address is required"), false
+	}
+
+	if len(account.Password) < 6 {
+		return u.Message(false, "Password is required"), false
+	}
+
+	//Email must be unique
+	temp := &Account{}
+
+	//check for errors and duplicate emails
+	err := GetDB().Table("accounts").Where("email = ?", account.Email).First(temp).Error
+	if err != nil && err != gorm.ErrRecordNotFound {
+		return u.Message(false, "Connection error. Please retry"), false
+	}
+	if temp.Email != "" {
+		return u.Message(false, "Email address already in use by another user."), false
+	}
+
+	return u.Message(false, "Requirement passed"), true
+}
+
+func (account *Account) Create() map[string]interface{} {
+
+	if resp, ok := account.Validate(); !ok {
+		return resp
+	}
+
+	hashedPassword, _ := bcrypt.GenerateFromPassword([]byte(account.Password), bcrypt.DefaultCost)
+	account.Password = string(hashedPassword)
+
+	GetDB().Create(account)
+
+	if account.ID <= 0 {
+		return u.Message(false, "Failed to create account, connection error.")
+	}
+
+	//Create new JWT token for the newly registered account
+	tk := &Token{UserId: account.ID}
+	token := jwt.NewWithClaims(jwt.GetSigningMethod("HS256"), tk)
+	tokenString, _ := token.SignedString([]byte(os.Getenv("token_password")))
+	account.Token = tokenString
+
+	account.Password = "" //delete password
+
+	response := u.Message(true, "Account has been created")
+	response["account"] = account
+	return response
+}
+
+func Login(email, password string) map[string]interface{} {
+
+	account := &Account{}
+	err := GetDB().Table("accounts").Where("email = ?", email).First(account).Error
+	if err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return u.Message(false, "Email address not found")
+		}
+		return u.Message(false, "Connection error. Please retry")
+	}
+
+	err = bcrypt.CompareHashAndPassword([]byte(account.Password), []byte(password))
+	if err != nil && err == bcrypt.ErrMismatchedHashAndPassword { //Password does not match!
+		return u.Message(false, "Invalid login credentials. Please try again")
+	}
+	//Worked! Logged In
+	account.Password = ""
+
+	//Create JWT token
+	tk := &Token{UserId: account.ID}
+	token := jwt.NewWithClaims(jwt.GetSigningMethod("HS256"), tk)
+	tokenString, _ := token.SignedString([]byte(os.Getenv("token_password")))
+	account.Token = tokenString //Store the token in the response
+
+	resp := u.Message(true, "Logged In")
+	resp["account"] = account
+	return resp
+}
+
+func GetUser(u uint) *Account {
+
+	acc := &Account{}
+	GetDB().Table("accounts").Where("id = ?", u).First(acc)
+	if acc.Email == "" { //User not found!
+		return nil
+	}
+
+	acc.Password = ""
+	return acc
+}
@@ -0,0 +1,39 @@
+package models
+
+import (
+	"fmt"
+	"github.com/jinzhu/gorm"
+	_ "github.com/jinzhu/gorm/dialects/postgres"
+	"github.com/joho/godotenv"
+	"os"
+)
+
+var db *gorm.DB
+
+func init() {
+
+	e := godotenv.Load()
+	if e != nil {
+		fmt.Print(e)
+	}
+
+	username := os.Getenv("db_user")
+	password := os.Getenv("db_pass")
+	dbName := os.Getenv("db_name")
+	dbHost := os.Getenv("db_host")
+
+	dbUri := fmt.Sprintf("host=%s port=5432 user=%s dbname=%s sslmode=disable password=%s", dbHost, username, dbName, password)
+	fmt.Println(dbUri)
+
+	conn, err := gorm.Open("postgres", "host=localhost port=5432 user=postgres dbname=users sslmode=disable password=#Avrilla8")
+	if err != nil {
+		fmt.Print(err)
+	}
+
+	db = conn
+	db.Debug().AutoMigrate(&Account{})
+}
+
+func GetDB() *gorm.DB {
+	return db
+}
@@ -0,0 +1,15 @@
+package utils
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+func Message(status bool, message string) (map[string]interface{}) {
+	return map[string]interface{}{"status": status, "message": message}
+}
+
+func Respond(w http.ResponseWriter, data map[string]interface{}) {
+	w.Header().Add("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(data)
+}
@@ -0,0 +1,4 @@
+.DS_Store
+bin
+
+
@@ -0,0 +1,13 @@
+language: go
+
+script:
+    - go vet ./...
+    - go test -v ./...
+
+go:
+  - 1.3
+  - 1.4
+  - 1.5
+  - 1.6
+  - 1.7
+  - tip
@@ -0,0 +1,8 @@
+Copyright (c) 2012 Dave Grijalva
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
@@ -0,0 +1,97 @@
+## Migration Guide from v2 -> v3
+
+Version 3 adds several new, frequently requested features.  To do so, it introduces a few breaking changes.  We've worked to keep these as minimal as possible.  This guide explains the breaking changes and how you can quickly update your code.
+
+### `Token.Claims` is now an interface type
+
+The most requested feature from the 2.0 verison of this library was the ability to provide a custom type to the JSON parser for claims. This was implemented by introducing a new interface, `Claims`, to replace `map[string]interface{}`.  We also included two concrete implementations of `Claims`: `MapClaims` and `StandardClaims`.
+
+`MapClaims` is an alias for `map[string]interface{}` with built in validation behavior.  It is the default claims type when using `Parse`.  The usage is unchanged except you must type cast the claims property.
+
+The old example for parsing a token looked like this..
+
+```go
+	if token, err := jwt.Parse(tokenString, keyLookupFunc); err == nil {
+		fmt.Printf("Token for user %v expires %v", token.Claims["user"], token.Claims["exp"])
+	}
+```
+
+is now directly mapped to...
+
+```go
+	if token, err := jwt.Parse(tokenString, keyLookupFunc); err == nil {
+		claims := token.Claims.(jwt.MapClaims)
+		fmt.Printf("Token for user %v expires %v", claims["user"], claims["exp"])
+	}
+```
+
+`StandardClaims` is designed to be embedded in your custom type.  You can supply a custom claims type with the new `ParseWithClaims` function.  Here's an example of using a custom claims type.
+
+```go
+	type MyCustomClaims struct {
+		User string
+		*StandardClaims
+	}
+	
+	if token, err := jwt.ParseWithClaims(tokenString, &MyCustomClaims{}, keyLookupFunc); err == nil {
+		claims := token.Claims.(*MyCustomClaims)
+		fmt.Printf("Token for user %v expires %v", claims.User, claims.StandardClaims.ExpiresAt)
+	}
+```
+
+### `ParseFromRequest` has been moved
+
+To keep this library focused on the tokens without becoming overburdened with complex request processing logic, `ParseFromRequest` and its new companion `ParseFromRequestWithClaims` have been moved to a subpackage, `request`.  The method signatues have also been augmented to receive a new argument: `Extractor`.
+
+`Extractors` do the work of picking the token string out of a request.  The interface is simple and composable.
+
+This simple parsing example:
+
+```go
+	if token, err := jwt.ParseFromRequest(tokenString, req, keyLookupFunc); err == nil {
+		fmt.Printf("Token for user %v expires %v", token.Claims["user"], token.Claims["exp"])
+	}
+```
+
+is directly mapped to:
+
+```go
+	if token, err := request.ParseFromRequest(req, request.OAuth2Extractor, keyLookupFunc); err == nil {
+		claims := token.Claims.(jwt.MapClaims)
+		fmt.Printf("Token for user %v expires %v", claims["user"], claims["exp"])
+	}
+```
+
+There are several concrete `Extractor` types provided for your convenience:
+
+* `HeaderExtractor` will search a list of headers until one contains content.
+* `ArgumentExtractor` will search a list of keys in request query and form arguments until one contains content.
+* `MultiExtractor` will try a list of `Extractors` in order until one returns content.
+* `AuthorizationHeaderExtractor` will look in the `Authorization` header for a `Bearer` token.
+* `OAuth2Extractor` searches the places an OAuth2 token would be specified (per the spec): `Authorization` header and `access_token` argument
+* `PostExtractionFilter` wraps an `Extractor`, allowing you to process the content before it's parsed.  A simple example is stripping the `Bearer ` text from a header
+
+
+### RSA signing methods no longer accept `[]byte` keys
+
+Due to a [critical vulnerability](https://auth0.com/blog/2015/03/31/critical-vulnerabilities-in-json-web-token-libraries/), we've decided the convenience of accepting `[]byte` instead of `rsa.PublicKey` or `rsa.PrivateKey` isn't worth the risk of misuse.
+
+To replace this behavior, we've added two helper methods: `ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error)` and `ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error)`.  These are just simple helpers for unpacking PEM encoded PKCS1 and PKCS8 keys. If your keys are encoded any other way, all you need to do is convert them to the `crypto/rsa` package's types.
+
+```go 
+	func keyLookupFunc(*Token) (interface{}, error) {
+		// Don't forget to validate the alg is what you expect:
+		if _, ok := token.Method.(*jwt.SigningMethodRSA); !ok {
+			return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
+		}
+		
+		// Look up key 
+		key, err := lookupPublicKey(token.Header["kid"])
+		if err != nil {
+			return nil, err
+		}
+		
+		// Unpack key from PEM encoded PKCS8
+		return jwt.ParseRSAPublicKeyFromPEM(key)
+	}
+```
@@ -0,0 +1,104 @@
+# jwt-go
+
+[![Build Status](https://travis-ci.org/dgrijalva/jwt-go.svg?branch=master)](https://travis-ci.org/dgrijalva/jwt-go)
+[![GoDoc](https://godoc.org/github.com/dgrijalva/jwt-go?status.svg)](https://godoc.org/github.com/dgrijalva/jwt-go)
+
+A [go](http://www.golang.org) (or 'golang' for search engine friendliness) implementation of [JSON Web Tokens](http://self-issued.info/docs/draft-ietf-oauth-json-web-token.html)
+
+**NEW VERSION COMING:** There have been a lot of improvements suggested since the version 3.0.0 released in 2016. I'm working now on cutting two different releases: 3.2.0 will contain any non-breaking changes or enhancements. 4.0.0 will follow shortly which will include breaking changes. See the 4.0.0 milestone to get an idea of what's coming. If you have other ideas, or would like to participate in 4.0.0, now's the time. If you depend on this library and don't want to be interrupted, I recommend you use your dependency mangement tool to pin to version 3. 
+
+**SECURITY NOTICE:** Some older versions of Go have a security issue in the cryotp/elliptic. Recommendation is to upgrade to at least 1.8.3. See issue #216 for more detail.
+
+**SECURITY NOTICE:** It's important that you [validate the `alg` presented is what you expect](https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/). This library attempts to make it easy to do the right thing by requiring key types match the expected alg, but you should take the extra step to verify it in your usage.  See the examples provided.
+
+## What the heck is a JWT?
+
+JWT.io has [a great introduction](https://jwt.io/introduction) to JSON Web Tokens.
+
+In short, it's a signed JSON object that does something useful (for example, authentication).  It's commonly used for `Bearer` tokens in Oauth 2.  A token is made of three parts, separated by `.`'s.  The first two parts are JSON objects, that have been [base64url](http://tools.ietf.org/html/rfc4648) encoded.  The last part is the signature, encoded the same way.
+
+The first part is called the header.  It contains the necessary information for verifying the last part, the signature.  For example, which encryption method was used for signing and what key was used.
+
+The part in the middle is the interesting bit.  It's called the Claims and contains the actual stuff you care about.  Refer to [the RFC](http://self-issued.info/docs/draft-ietf-oauth-json-web-token.html) for information about reserved keys and the proper way to add your own.
+
+## What's in the box?
+
+This library supports the parsing and verification as well as the generation and signing of JWTs.  Current supported signing algorithms are HMAC SHA, RSA, RSA-PSS, and ECDSA, though hooks are present for adding your own.
+
+## Examples
+
+See [the project documentation](https://godoc.org/github.com/dgrijalva/jwt-go) for examples of usage:
+
+* [Simple example of parsing and validating a token](https://godoc.org/github.com/dgrijalva/jwt-go#example-Parse--Hmac)
+* [Simple example of building and signing a token](https://godoc.org/github.com/dgrijalva/jwt-go#example-New--Hmac)
+* [Directory of Examples](https://godoc.org/github.com/dgrijalva/jwt-go#pkg-examples)
+
+## Extensions
+
+This library publishes all the necessary components for adding your own signing methods.  Simply implement the `SigningMethod` interface and register a factory method using `RegisterSigningMethod`.  
+
+Here's an example of an extension that integrates with multiple Google Cloud Platform signing tools (AppEngine, IAM API, Cloud KMS): https://github.com/someone1/gcp-jwt-go
+
+## Compliance
+
+This library was last reviewed to comply with [RTF 7519](http://www.rfc-editor.org/info/rfc7519) dated May 2015 with a few notable differences:
+
+* In order to protect against accidental use of [Unsecured JWTs](http://self-issued.info/docs/draft-ietf-oauth-json-web-token.html#UnsecuredJWT), tokens using `alg=none` will only be accepted if the constant `jwt.UnsafeAllowNoneSignatureType` is provided as the key.
+
+## Project Status & Versioning
+
+This library is considered production ready.  Feedback and feature requests are appreciated.  The API should be considered stable.  There should be very few backwards-incompatible changes outside of major version updates (and only with good reason).
+
+This project uses [Semantic Versioning 2.0.0](http://semver.org).  Accepted pull requests will land on `master`.  Periodically, versions will be tagged from `master`.  You can find all the releases on [the project releases page](https://github.com/dgrijalva/jwt-go/releases).
+
+While we try to make it obvious when we make breaking changes, there isn't a great mechanism for pushing announcements out to users.  You may want to use this alternative package include: `gopkg.in/dgrijalva/jwt-go.v3`.  It will do the right thing WRT semantic versioning.
+
+**BREAKING CHANGES:*** 
+* Version 3.0.0 includes _a lot_ of changes from the 2.x line, including a few that break the API.  We've tried to break as few things as possible, so there should just be a few type signature changes.  A full list of breaking changes is available in `VERSION_HISTORY.md`.  See `MIGRATION_GUIDE.md` for more information on updating your code.
+
+## Usage Tips
+
+### Signing vs Encryption
+
+A token is simply a JSON object that is signed by its author. this tells you exactly two things about the data:
+
+* The author of the token was in the possession of the signing secret
+* The data has not been modified since it was signed
+
+It's important to know that JWT does not provide encryption, which means anyone who has access to the token can read its contents. If you need to protect (encrypt) the data, there is a companion spec, `JWE`, that provides this functionality. JWE is currently outside the scope of this library.
+
+### Choosing a Signing Method
+
+There are several signing methods available, and you should probably take the time to learn about the various options before choosing one.  The principal design decision is most likely going to be symmetric vs asymmetric.
+
+Symmetric signing methods, such as HSA, use only a single secret. This is probably the simplest signing method to use since any `[]byte` can be used as a valid secret. They are also slightly computationally faster to use, though this rarely is enough to matter. Symmetric signing methods work the best when both producers and consumers of tokens are trusted, or even the same system. Since the same secret is used to both sign and validate tokens, you can't easily distribute the key for validation.
+
+Asymmetric signing methods, such as RSA, use different keys for signing and verifying tokens. This makes it possible to produce tokens with a private key, and allow any consumer to access the public key for verification.
+
+### Signing Methods and Key Types
+
+Each signing method expects a different object type for its signing keys. See the package documentation for details. Here are the most common ones:
+
+* The [HMAC signing method](https://godoc.org/github.com/dgrijalva/jwt-go#SigningMethodHMAC) (`HS256`,`HS384`,`HS512`) expect `[]byte` values for signing and validation
+* The [RSA signing method](https://godoc.org/github.com/dgrijalva/jwt-go#SigningMethodRSA) (`RS256`,`RS384`,`RS512`) expect `*rsa.PrivateKey` for signing and `*rsa.PublicKey` for validation
+* The [ECDSA signing method](https://godoc.org/github.com/dgrijalva/jwt-go#SigningMethodECDSA) (`ES256`,`ES384`,`ES512`) expect `*ecdsa.PrivateKey` for signing and `*ecdsa.PublicKey` for validation
+
+### JWT and OAuth
+
+It's worth mentioning that OAuth and JWT are not the same thing. A JWT token is simply a signed JSON object. It can be used anywhere such a thing is useful. There is some confusion, though, as JWT is the most common type of bearer token used in OAuth2 authentication.
+
+Without going too far down the rabbit hole, here's a description of the interaction of these technologies:
+
+* OAuth is a protocol for allowing an identity provider to be separate from the service a user is logging in to. For example, whenever you use Facebook to log into a different service (Yelp, Spotify, etc), you are using OAuth.
+* OAuth defines several options for passing around authentication data. One popular method is called a "bearer token". A bearer token is simply a string that _should_ only be held by an authenticated user. Thus, simply presenting this token proves your identity. You can probably derive from here why a JWT might make a good bearer token.
+* Because bearer tokens are used for authentication, it's important they're kept secret. This is why transactions that use bearer tokens typically happen over SSL.
+
+### Troubleshooting
+
+This library uses descriptive error messages whenever possible. If you are not getting the expected result, have a look at the errors. The most common place people get stuck is providing the correct type of key to the parser. See the above section on signing methods and key types.
+
+## More
+
+Documentation can be found [on godoc.org](http://godoc.org/github.com/dgrijalva/jwt-go).
+
+The command line utility included in this project (cmd/jwt) provides a straightforward example of token creation and parsing as well as a useful tool for debugging your own integration. You'll also find several implementation examples in the documentation.
@@ -0,0 +1,118 @@
+## `jwt-go` Version History
+
+#### 3.2.0
+
+* Added method `ParseUnverified` to allow users to split up the tasks of parsing and validation
+* HMAC signing method returns `ErrInvalidKeyType` instead of `ErrInvalidKey` where appropriate
+* Added options to `request.ParseFromRequest`, which allows for an arbitrary list of modifiers to parsing behavior. Initial set include `WithClaims` and `WithParser`. Existing usage of this function will continue to work as before.
+* Deprecated `ParseFromRequestWithClaims` to simplify API in the future.
+
+#### 3.1.0
+
+* Improvements to `jwt` command line tool
+* Added `SkipClaimsValidation` option to `Parser`
+* Documentation updates
+
+#### 3.0.0
+
+* **Compatibility Breaking Changes**: See MIGRATION_GUIDE.md for tips on updating your code
+	* Dropped support for `[]byte` keys when using RSA signing methods.  This convenience feature could contribute to security vulnerabilities involving mismatched key types with signing methods.
+	* `ParseFromRequest` has been moved to `request` subpackage and usage has changed
+	* The `Claims` property on `Token` is now type `Claims` instead of `map[string]interface{}`.  The default value is type `MapClaims`, which is an alias to `map[string]interface{}`.  This makes it possible to use a custom type when decoding claims.
+* Other Additions and Changes
+	* Added `Claims` interface type to allow users to decode the claims into a custom type
+	* Added `ParseWithClaims`, which takes a third argument of type `Claims`.  Use this function instead of `Parse` if you have a custom type you'd like to decode into.
+	* Dramatically improved the functionality and flexibility of `ParseFromRequest`, which is now in the `request` subpackage
+	* Added `ParseFromRequestWithClaims` which is the `FromRequest` equivalent of `ParseWithClaims`
+	* Added new interface type `Extractor`, which is used for extracting JWT strings from http requests.  Used with `ParseFromRequest` and `ParseFromRequestWithClaims`.
+	* Added several new, more specific, validation errors to error type bitmask
+	* Moved examples from README to executable example files
+	* Signing method registry is now thread safe
+	* Added new property to `ValidationError`, which contains the raw error returned by calls made by parse/verify (such as those returned by keyfunc or json parser)
+
+#### 2.7.0
+
+This will likely be the last backwards compatible release before 3.0.0, excluding essential bug fixes.
+
+* Added new option `-show` to the `jwt` command that will just output the decoded token without verifying
+* Error text for expired tokens includes how long it's been expired
+* Fixed incorrect error returned from `ParseRSAPublicKeyFromPEM`
+* Documentation updates
+
+#### 2.6.0
+
+* Exposed inner error within ValidationError
+* Fixed validation errors when using UseJSONNumber flag
+* Added several unit tests
+
+#### 2.5.0
+
+* Added support for signing method none.  You shouldn't use this.  The API tries to make this clear.
+* Updated/fixed some documentation
+* Added more helpful error message when trying to parse tokens that begin with `BEARER `
+
+#### 2.4.0
+
+* Added new type, Parser, to allow for configuration of various parsing parameters
+	* You can now specify a list of valid signing methods.  Anything outside this set will be rejected.
+	* You can now opt to use the `json.Number` type instead of `float64` when parsing token JSON
+* Added support for [Travis CI](https://travis-ci.org/dgrijalva/jwt-go)
+* Fixed some bugs with ECDSA parsing
+
+#### 2.3.0
+
+* Added support for ECDSA signing methods
+* Added support for RSA PSS signing methods (requires go v1.4)
+
+#### 2.2.0
+
+* Gracefully handle a `nil` `Keyfunc` being passed to `Parse`.  Result will now be the parsed token and an error, instead of a panic.
+
+#### 2.1.0
+
+Backwards compatible API change that was missed in 2.0.0.
+
+* The `SignedString` method on `Token` now takes `interface{}` instead of `[]byte`
+
+#### 2.0.0
+
+There were two major reasons for breaking backwards compatibility with this update.  The first was a refactor required to expand the width of the RSA and HMAC-SHA signing implementations.  There will likely be no required code changes to support this change.
+
+The second update, while unfortunately requiring a small change in integration, is required to open up this library to other signing methods.  Not all keys used for all signing methods have a single standard on-disk representation.  Requiring `[]byte` as the type for all keys proved too limiting.  Additionally, this implementation allows for pre-parsed tokens to be reused, which might matter in an application that parses a high volume of tokens with a small set of keys.  Backwards compatibilty has been maintained for passing `[]byte` to the RSA signing methods, but they will also accept `*rsa.PublicKey` and `*rsa.PrivateKey`.
+
+It is likely the only integration change required here will be to change `func(t *jwt.Token) ([]byte, error)` to `func(t *jwt.Token) (interface{}, error)` when calling `Parse`.
+
+* **Compatibility Breaking Changes**
+	* `SigningMethodHS256` is now `*SigningMethodHMAC` instead of `type struct`
+	* `SigningMethodRS256` is now `*SigningMethodRSA` instead of `type struct`
+	* `KeyFunc` now returns `interface{}` instead of `[]byte`
+	* `SigningMethod.Sign` now takes `interface{}` instead of `[]byte` for the key
+	* `SigningMethod.Verify` now takes `interface{}` instead of `[]byte` for the key
+* Renamed type `SigningMethodHS256` to `SigningMethodHMAC`.  Specific sizes are now just instances of this type.
+    * Added public package global `SigningMethodHS256`
+    * Added public package global `SigningMethodHS384`
+    * Added public package global `SigningMethodHS512`
+* Renamed type `SigningMethodRS256` to `SigningMethodRSA`.  Specific sizes are now just instances of this type.
+    * Added public package global `SigningMethodRS256`
+    * Added public package global `SigningMethodRS384`
+    * Added public package global `SigningMethodRS512`
+* Moved sample private key for HMAC tests from an inline value to a file on disk.  Value is unchanged.
+* Refactored the RSA implementation to be easier to read
+* Exposed helper methods `ParseRSAPrivateKeyFromPEM` and `ParseRSAPublicKeyFromPEM`
+
+#### 1.0.2
+
+* Fixed bug in parsing public keys from certificates
+* Added more tests around the parsing of keys for RS256
+* Code refactoring in RS256 implementation.  No functional changes
+
+#### 1.0.1
+
+* Fixed panic if RS256 signing method was passed an invalid key
+
+#### 1.0.0
+
+* First versioned release
+* API stabilized
+* Supports creating, signing, parsing, and validating JWT tokens
+* Supports RS256 and HS256 signing methods
@@ -0,0 +1,134 @@
+package jwt
+
+import (
+	"crypto/subtle"
+	"fmt"
+	"time"
+)
+
+// For a type to be a Claims object, it must just have a Valid method that determines
+// if the token is invalid for any supported reason
+type Claims interface {
+	Valid() error
+}
+
+// Structured version of Claims Section, as referenced at
+// https://tools.ietf.org/html/rfc7519#section-4.1
+// See examples for how to use this with your own claim types
+type StandardClaims struct {
+	Audience  string `json:"aud,omitempty"`
+	ExpiresAt int64  `json:"exp,omitempty"`
+	Id        string `json:"jti,omitempty"`
+	IssuedAt  int64  `json:"iat,omitempty"`
+	Issuer    string `json:"iss,omitempty"`
+	NotBefore int64  `json:"nbf,omitempty"`
+	Subject   string `json:"sub,omitempty"`
+}
+
+// Validates time based claims "exp, iat, nbf".
+// There is no accounting for clock skew.
+// As well, if any of the above claims are not in the token, it will still
+// be considered a valid claim.
+func (c StandardClaims) Valid() error {
+	vErr := new(ValidationError)
+	now := TimeFunc().Unix()
+
+	// The claims below are optional, by default, so if they are set to the
+	// default value in Go, let's not fail the verification for them.
+	if c.VerifyExpiresAt(now, false) == false {
+		delta := time.Unix(now, 0).Sub(time.Unix(c.ExpiresAt, 0))
+		vErr.Inner = fmt.Errorf("token is expired by %v", delta)
+		vErr.Errors |= ValidationErrorExpired
+	}
+
+	if c.VerifyIssuedAt(now, false) == false {
+		vErr.Inner = fmt.Errorf("Token used before issued")
+		vErr.Errors |= ValidationErrorIssuedAt
+	}
+
+	if c.VerifyNotBefore(now, false) == false {
+		vErr.Inner = fmt.Errorf("token is not valid yet")
+		vErr.Errors |= ValidationErrorNotValidYet
+	}
+
+	if vErr.valid() {
+		return nil
+	}
+
+	return vErr
+}
+
+// Compares the aud claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (c *StandardClaims) VerifyAudience(cmp string, req bool) bool {
+	return verifyAud(c.Audience, cmp, req)
+}
+
+// Compares the exp claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (c *StandardClaims) VerifyExpiresAt(cmp int64, req bool) bool {
+	return verifyExp(c.ExpiresAt, cmp, req)
+}
+
+// Compares the iat claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (c *StandardClaims) VerifyIssuedAt(cmp int64, req bool) bool {
+	return verifyIat(c.IssuedAt, cmp, req)
+}
+
+// Compares the iss claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (c *StandardClaims) VerifyIssuer(cmp string, req bool) bool {
+	return verifyIss(c.Issuer, cmp, req)
+}
+
+// Compares the nbf claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (c *StandardClaims) VerifyNotBefore(cmp int64, req bool) bool {
+	return verifyNbf(c.NotBefore, cmp, req)
+}
+
+// ----- helpers
+
+func verifyAud(aud string, cmp string, required bool) bool {
+	if aud == "" {
+		return !required
+	}
+	if subtle.ConstantTimeCompare([]byte(aud), []byte(cmp)) != 0 {
+		return true
+	} else {
+		return false
+	}
+}
+
+func verifyExp(exp int64, now int64, required bool) bool {
+	if exp == 0 {
+		return !required
+	}
+	return now <= exp
+}
+
+func verifyIat(iat int64, now int64, required bool) bool {
+	if iat == 0 {
+		return !required
+	}
+	return now >= iat
+}
+
+func verifyIss(iss string, cmp string, required bool) bool {
+	if iss == "" {
+		return !required
+	}
+	if subtle.ConstantTimeCompare([]byte(iss), []byte(cmp)) != 0 {
+		return true
+	} else {
+		return false
+	}
+}
+
+func verifyNbf(nbf int64, now int64, required bool) bool {
+	if nbf == 0 {
+		return !required
+	}
+	return now >= nbf
+}
@@ -0,0 +1,4 @@
+// Package jwt is a Go implementation of JSON Web Tokens: http://self-issued.info/docs/draft-jones-json-web-token.html
+//
+// See README.md for more info.
+package jwt
@@ -0,0 +1,148 @@
+package jwt
+
+import (
+	"crypto"
+	"crypto/ecdsa"
+	"crypto/rand"
+	"errors"
+	"math/big"
+)
+
+var (
+	// Sadly this is missing from crypto/ecdsa compared to crypto/rsa
+	ErrECDSAVerification = errors.New("crypto/ecdsa: verification error")
+)
+
+// Implements the ECDSA family of signing methods signing methods
+// Expects *ecdsa.PrivateKey for signing and *ecdsa.PublicKey for verification
+type SigningMethodECDSA struct {
+	Name      string
+	Hash      crypto.Hash
+	KeySize   int
+	CurveBits int
+}
+
+// Specific instances for EC256 and company
+var (
+	SigningMethodES256 *SigningMethodECDSA
+	SigningMethodES384 *SigningMethodECDSA
+	SigningMethodES512 *SigningMethodECDSA
+)
+
+func init() {
+	// ES256
+	SigningMethodES256 = &SigningMethodECDSA{"ES256", crypto.SHA256, 32, 256}
+	RegisterSigningMethod(SigningMethodES256.Alg(), func() SigningMethod {
+		return SigningMethodES256
+	})
+
+	// ES384
+	SigningMethodES384 = &SigningMethodECDSA{"ES384", crypto.SHA384, 48, 384}
+	RegisterSigningMethod(SigningMethodES384.Alg(), func() SigningMethod {
+		return SigningMethodES384
+	})
+
+	// ES512
+	SigningMethodES512 = &SigningMethodECDSA{"ES512", crypto.SHA512, 66, 521}
+	RegisterSigningMethod(SigningMethodES512.Alg(), func() SigningMethod {
+		return SigningMethodES512
+	})
+}
+
+func (m *SigningMethodECDSA) Alg() string {
+	return m.Name
+}
+
+// Implements the Verify method from SigningMethod
+// For this verify method, key must be an ecdsa.PublicKey struct
+func (m *SigningMethodECDSA) Verify(signingString, signature string, key interface{}) error {
+	var err error
+
+	// Decode the signature
+	var sig []byte
+	if sig, err = DecodeSegment(signature); err != nil {
+		return err
+	}
+
+	// Get the key
+	var ecdsaKey *ecdsa.PublicKey
+	switch k := key.(type) {
+	case *ecdsa.PublicKey:
+		ecdsaKey = k
+	default:
+		return ErrInvalidKeyType
+	}
+
+	if len(sig) != 2*m.KeySize {
+		return ErrECDSAVerification
+	}
+
+	r := big.NewInt(0).SetBytes(sig[:m.KeySize])
+	s := big.NewInt(0).SetBytes(sig[m.KeySize:])
+
+	// Create hasher
+	if !m.Hash.Available() {
+		return ErrHashUnavailable
+	}
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	// Verify the signature
+	if verifystatus := ecdsa.Verify(ecdsaKey, hasher.Sum(nil), r, s); verifystatus == true {
+		return nil
+	} else {
+		return ErrECDSAVerification
+	}
+}
+
+// Implements the Sign method from SigningMethod
+// For this signing method, key must be an ecdsa.PrivateKey struct
+func (m *SigningMethodECDSA) Sign(signingString string, key interface{}) (string, error) {
+	// Get the key
+	var ecdsaKey *ecdsa.PrivateKey
+	switch k := key.(type) {
+	case *ecdsa.PrivateKey:
+		ecdsaKey = k
+	default:
+		return "", ErrInvalidKeyType
+	}
+
+	// Create the hasher
+	if !m.Hash.Available() {
+		return "", ErrHashUnavailable
+	}
+
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	// Sign the string and return r, s
+	if r, s, err := ecdsa.Sign(rand.Reader, ecdsaKey, hasher.Sum(nil)); err == nil {
+		curveBits := ecdsaKey.Curve.Params().BitSize
+
+		if m.CurveBits != curveBits {
+			return "", ErrInvalidKey
+		}
+
+		keyBytes := curveBits / 8
+		if curveBits%8 > 0 {
+			keyBytes += 1
+		}
+
+		// We serialize the outpus (r and s) into big-endian byte arrays and pad
+		// them with zeros on the left to make sure the sizes work out. Both arrays
+		// must be keyBytes long, and the output must be 2*keyBytes long.
+		rBytes := r.Bytes()
+		rBytesPadded := make([]byte, keyBytes)
+		copy(rBytesPadded[keyBytes-len(rBytes):], rBytes)
+
+		sBytes := s.Bytes()
+		sBytesPadded := make([]byte, keyBytes)
+		copy(sBytesPadded[keyBytes-len(sBytes):], sBytes)
+
+		out := append(rBytesPadded, sBytesPadded...)
+
+		return EncodeSegment(out), nil
+	} else {
+		return "", err
+	}
+}
@@ -0,0 +1,69 @@
+package jwt
+
+import (
+	"crypto/ecdsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+)
+
+var (
+	ErrNotECPublicKey  = errors.New("Key is not a valid ECDSA public key")
+	ErrNotECPrivateKey = errors.New("Key is not a valid ECDSA private key")
+)
+
+// Parse PEM encoded Elliptic Curve Private Key Structure
+func ParseECPrivateKeyFromPEM(key []byte) (*ecdsa.PrivateKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	// Parse the key
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParseECPrivateKey(block.Bytes); err != nil {
+		if parsedKey, err = x509.ParsePKCS8PrivateKey(block.Bytes); err != nil {
+			return nil, err
+		}
+	}
+
+	var pkey *ecdsa.PrivateKey
+	var ok bool
+	if pkey, ok = parsedKey.(*ecdsa.PrivateKey); !ok {
+		return nil, ErrNotECPrivateKey
+	}
+
+	return pkey, nil
+}
+
+// Parse PEM encoded PKCS1 or PKCS8 public key
+func ParseECPublicKeyFromPEM(key []byte) (*ecdsa.PublicKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	// Parse the key
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
+		if cert, err := x509.ParseCertificate(block.Bytes); err == nil {
+			parsedKey = cert.PublicKey
+		} else {
+			return nil, err
+		}
+	}
+
+	var pkey *ecdsa.PublicKey
+	var ok bool
+	if pkey, ok = parsedKey.(*ecdsa.PublicKey); !ok {
+		return nil, ErrNotECPublicKey
+	}
+
+	return pkey, nil
+}
@@ -0,0 +1,59 @@
+package jwt
+
+import (
+	"errors"
+)
+
+// Error constants
+var (
+	ErrInvalidKey      = errors.New("key is invalid")
+	ErrInvalidKeyType  = errors.New("key is of invalid type")
+	ErrHashUnavailable = errors.New("the requested hash function is unavailable")
+)
+
+// The errors that might occur when parsing and validating a token
+const (
+	ValidationErrorMalformed        uint32 = 1 << iota // Token is malformed
+	ValidationErrorUnverifiable                        // Token could not be verified because of signing problems
+	ValidationErrorSignatureInvalid                    // Signature validation failed
+
+	// Standard Claim validation errors
+	ValidationErrorAudience      // AUD validation failed
+	ValidationErrorExpired       // EXP validation failed
+	ValidationErrorIssuedAt      // IAT validation failed
+	ValidationErrorIssuer        // ISS validation failed
+	ValidationErrorNotValidYet   // NBF validation failed
+	ValidationErrorId            // JTI validation failed
+	ValidationErrorClaimsInvalid // Generic claims validation error
+)
+
+// Helper for constructing a ValidationError with a string error message
+func NewValidationError(errorText string, errorFlags uint32) *ValidationError {
+	return &ValidationError{
+		text:   errorText,
+		Errors: errorFlags,
+	}
+}
+
+// The error from Parse if token is not valid
+type ValidationError struct {
+	Inner  error  // stores the error returned by external dependencies, i.e.: KeyFunc
+	Errors uint32 // bitfield.  see ValidationError... constants
+	text   string // errors that do not have a valid error just have text
+}
+
+// Validation error is an error type
+func (e ValidationError) Error() string {
+	if e.Inner != nil {
+		return e.Inner.Error()
+	} else if e.text != "" {
+		return e.text
+	} else {
+		return "token is invalid"
+	}
+}
+
+// No errors
+func (e *ValidationError) valid() bool {
+	return e.Errors == 0
+}
@@ -0,0 +1,95 @@
+package jwt
+
+import (
+	"crypto"
+	"crypto/hmac"
+	"errors"
+)
+
+// Implements the HMAC-SHA family of signing methods signing methods
+// Expects key type of []byte for both signing and validation
+type SigningMethodHMAC struct {
+	Name string
+	Hash crypto.Hash
+}
+
+// Specific instances for HS256 and company
+var (
+	SigningMethodHS256  *SigningMethodHMAC
+	SigningMethodHS384  *SigningMethodHMAC
+	SigningMethodHS512  *SigningMethodHMAC
+	ErrSignatureInvalid = errors.New("signature is invalid")
+)
+
+func init() {
+	// HS256
+	SigningMethodHS256 = &SigningMethodHMAC{"HS256", crypto.SHA256}
+	RegisterSigningMethod(SigningMethodHS256.Alg(), func() SigningMethod {
+		return SigningMethodHS256
+	})
+
+	// HS384
+	SigningMethodHS384 = &SigningMethodHMAC{"HS384", crypto.SHA384}
+	RegisterSigningMethod(SigningMethodHS384.Alg(), func() SigningMethod {
+		return SigningMethodHS384
+	})
+
+	// HS512
+	SigningMethodHS512 = &SigningMethodHMAC{"HS512", crypto.SHA512}
+	RegisterSigningMethod(SigningMethodHS512.Alg(), func() SigningMethod {
+		return SigningMethodHS512
+	})
+}
+
+func (m *SigningMethodHMAC) Alg() string {
+	return m.Name
+}
+
+// Verify the signature of HSXXX tokens.  Returns nil if the signature is valid.
+func (m *SigningMethodHMAC) Verify(signingString, signature string, key interface{}) error {
+	// Verify the key is the right type
+	keyBytes, ok := key.([]byte)
+	if !ok {
+		return ErrInvalidKeyType
+	}
+
+	// Decode signature, for comparison
+	sig, err := DecodeSegment(signature)
+	if err != nil {
+		return err
+	}
+
+	// Can we use the specified hashing method?
+	if !m.Hash.Available() {
+		return ErrHashUnavailable
+	}
+
+	// This signing method is symmetric, so we validate the signature
+	// by reproducing the signature from the signing string and key, then
+	// comparing that against the provided signature.
+	hasher := hmac.New(m.Hash.New, keyBytes)
+	hasher.Write([]byte(signingString))
+	if !hmac.Equal(sig, hasher.Sum(nil)) {
+		return ErrSignatureInvalid
+	}
+
+	// No validation errors.  Signature is good.
+	return nil
+}
+
+// Implements the Sign method from SigningMethod for this signing method.
+// Key must be []byte
+func (m *SigningMethodHMAC) Sign(signingString string, key interface{}) (string, error) {
+	if keyBytes, ok := key.([]byte); ok {
+		if !m.Hash.Available() {
+			return "", ErrHashUnavailable
+		}
+
+		hasher := hmac.New(m.Hash.New, keyBytes)
+		hasher.Write([]byte(signingString))
+
+		return EncodeSegment(hasher.Sum(nil)), nil
+	}
+
+	return "", ErrInvalidKeyType
+}
@@ -0,0 +1,94 @@
+package jwt
+
+import (
+	"encoding/json"
+	"errors"
+	// "fmt"
+)
+
+// Claims type that uses the map[string]interface{} for JSON decoding
+// This is the default claims type if you don't supply one
+type MapClaims map[string]interface{}
+
+// Compares the aud claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (m MapClaims) VerifyAudience(cmp string, req bool) bool {
+	aud, _ := m["aud"].(string)
+	return verifyAud(aud, cmp, req)
+}
+
+// Compares the exp claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (m MapClaims) VerifyExpiresAt(cmp int64, req bool) bool {
+	switch exp := m["exp"].(type) {
+	case float64:
+		return verifyExp(int64(exp), cmp, req)
+	case json.Number:
+		v, _ := exp.Int64()
+		return verifyExp(v, cmp, req)
+	}
+	return req == false
+}
+
+// Compares the iat claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (m MapClaims) VerifyIssuedAt(cmp int64, req bool) bool {
+	switch iat := m["iat"].(type) {
+	case float64:
+		return verifyIat(int64(iat), cmp, req)
+	case json.Number:
+		v, _ := iat.Int64()
+		return verifyIat(v, cmp, req)
+	}
+	return req == false
+}
+
+// Compares the iss claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (m MapClaims) VerifyIssuer(cmp string, req bool) bool {
+	iss, _ := m["iss"].(string)
+	return verifyIss(iss, cmp, req)
+}
+
+// Compares the nbf claim against cmp.
+// If required is false, this method will return true if the value matches or is unset
+func (m MapClaims) VerifyNotBefore(cmp int64, req bool) bool {
+	switch nbf := m["nbf"].(type) {
+	case float64:
+		return verifyNbf(int64(nbf), cmp, req)
+	case json.Number:
+		v, _ := nbf.Int64()
+		return verifyNbf(v, cmp, req)
+	}
+	return req == false
+}
+
+// Validates time based claims "exp, iat, nbf".
+// There is no accounting for clock skew.
+// As well, if any of the above claims are not in the token, it will still
+// be considered a valid claim.
+func (m MapClaims) Valid() error {
+	vErr := new(ValidationError)
+	now := TimeFunc().Unix()
+
+	if m.VerifyExpiresAt(now, false) == false {
+		vErr.Inner = errors.New("Token is expired")
+		vErr.Errors |= ValidationErrorExpired
+	}
+
+	if m.VerifyIssuedAt(now, false) == false {
+		vErr.Inner = errors.New("Token used before issued")
+		vErr.Errors |= ValidationErrorIssuedAt
+	}
+
+	if m.VerifyNotBefore(now, false) == false {
+		vErr.Inner = errors.New("Token is not valid yet")
+		vErr.Errors |= ValidationErrorNotValidYet
+	}
+
+	if vErr.valid() {
+		return nil
+	}
+
+	return vErr
+}
@@ -0,0 +1,52 @@
+package jwt
+
+// Implements the none signing method.  This is required by the spec
+// but you probably should never use it.
+var SigningMethodNone *signingMethodNone
+
+const UnsafeAllowNoneSignatureType unsafeNoneMagicConstant = "none signing method allowed"
+
+var NoneSignatureTypeDisallowedError error
+
+type signingMethodNone struct{}
+type unsafeNoneMagicConstant string
+
+func init() {
+	SigningMethodNone = &signingMethodNone{}
+	NoneSignatureTypeDisallowedError = NewValidationError("'none' signature type is not allowed", ValidationErrorSignatureInvalid)
+
+	RegisterSigningMethod(SigningMethodNone.Alg(), func() SigningMethod {
+		return SigningMethodNone
+	})
+}
+
+func (m *signingMethodNone) Alg() string {
+	return "none"
+}
+
+// Only allow 'none' alg type if UnsafeAllowNoneSignatureType is specified as the key
+func (m *signingMethodNone) Verify(signingString, signature string, key interface{}) (err error) {
+	// Key must be UnsafeAllowNoneSignatureType to prevent accidentally
+	// accepting 'none' signing method
+	if _, ok := key.(unsafeNoneMagicConstant); !ok {
+		return NoneSignatureTypeDisallowedError
+	}
+	// If signing method is none, signature must be an empty string
+	if signature != "" {
+		return NewValidationError(
+			"'none' signing method with non-empty signature",
+			ValidationErrorSignatureInvalid,
+		)
+	}
+
+	// Accept 'none' signing method.
+	return nil
+}
+
+// Only allow 'none' signing if UnsafeAllowNoneSignatureType is specified as the key
+func (m *signingMethodNone) Sign(signingString string, key interface{}) (string, error) {
+	if _, ok := key.(unsafeNoneMagicConstant); ok {
+		return "", nil
+	}
+	return "", NoneSignatureTypeDisallowedError
+}
@@ -0,0 +1,148 @@
+package jwt
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"strings"
+)
+
+type Parser struct {
+	ValidMethods         []string // If populated, only these methods will be considered valid
+	UseJSONNumber        bool     // Use JSON Number format in JSON decoder
+	SkipClaimsValidation bool     // Skip claims validation during token parsing
+}
+
+// Parse, validate, and return a token.
+// keyFunc will receive the parsed token and should return the key for validating.
+// If everything is kosher, err will be nil
+func (p *Parser) Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
+	return p.ParseWithClaims(tokenString, MapClaims{}, keyFunc)
+}
+
+func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
+	token, parts, err := p.ParseUnverified(tokenString, claims)
+	if err != nil {
+		return token, err
+	}
+
+	// Verify signing method is in the required set
+	if p.ValidMethods != nil {
+		var signingMethodValid = false
+		var alg = token.Method.Alg()
+		for _, m := range p.ValidMethods {
+			if m == alg {
+				signingMethodValid = true
+				break
+			}
+		}
+		if !signingMethodValid {
+			// signing method is not in the listed set
+			return token, NewValidationError(fmt.Sprintf("signing method %v is invalid", alg), ValidationErrorSignatureInvalid)
+		}
+	}
+
+	// Lookup key
+	var key interface{}
+	if keyFunc == nil {
+		// keyFunc was not provided.  short circuiting validation
+		return token, NewValidationError("no Keyfunc was provided.", ValidationErrorUnverifiable)
+	}
+	if key, err = keyFunc(token); err != nil {
+		// keyFunc returned an error
+		if ve, ok := err.(*ValidationError); ok {
+			return token, ve
+		}
+		return token, &ValidationError{Inner: err, Errors: ValidationErrorUnverifiable}
+	}
+
+	vErr := &ValidationError{}
+
+	// Validate Claims
+	if !p.SkipClaimsValidation {
+		if err := token.Claims.Valid(); err != nil {
+
+			// If the Claims Valid returned an error, check if it is a validation error,
+			// If it was another error type, create a ValidationError with a generic ClaimsInvalid flag set
+			if e, ok := err.(*ValidationError); !ok {
+				vErr = &ValidationError{Inner: err, Errors: ValidationErrorClaimsInvalid}
+			} else {
+				vErr = e
+			}
+		}
+	}
+
+	// Perform validation
+	token.Signature = parts[2]
+	if err = token.Method.Verify(strings.Join(parts[0:2], "."), token.Signature, key); err != nil {
+		vErr.Inner = err
+		vErr.Errors |= ValidationErrorSignatureInvalid
+	}
+
+	if vErr.valid() {
+		token.Valid = true
+		return token, nil
+	}
+
+	return token, vErr
+}
+
+// WARNING: Don't use this method unless you know what you're doing
+//
+// This method parses the token but doesn't validate the signature. It's only
+// ever useful in cases where you know the signature is valid (because it has
+// been checked previously in the stack) and you want to extract values from
+// it.
+func (p *Parser) ParseUnverified(tokenString string, claims Claims) (token *Token, parts []string, err error) {
+	parts = strings.Split(tokenString, ".")
+	if len(parts) != 3 {
+		return nil, parts, NewValidationError("token contains an invalid number of segments", ValidationErrorMalformed)
+	}
+
+	token = &Token{Raw: tokenString}
+
+	// parse Header
+	var headerBytes []byte
+	if headerBytes, err = DecodeSegment(parts[0]); err != nil {
+		if strings.HasPrefix(strings.ToLower(tokenString), "bearer ") {
+			return token, parts, NewValidationError("tokenstring should not contain 'bearer '", ValidationErrorMalformed)
+		}
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+	if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+
+	// parse Claims
+	var claimBytes []byte
+	token.Claims = claims
+
+	if claimBytes, err = DecodeSegment(parts[1]); err != nil {
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+	dec := json.NewDecoder(bytes.NewBuffer(claimBytes))
+	if p.UseJSONNumber {
+		dec.UseNumber()
+	}
+	// JSON Decode.  Special case for map type to avoid weird pointer behavior
+	if c, ok := token.Claims.(MapClaims); ok {
+		err = dec.Decode(&c)
+	} else {
+		err = dec.Decode(&claims)
+	}
+	// Handle decode error
+	if err != nil {
+		return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
+	}
+
+	// Lookup signature method
+	if method, ok := token.Header["alg"].(string); ok {
+		if token.Method = GetSigningMethod(method); token.Method == nil {
+			return token, parts, NewValidationError("signing method (alg) is unavailable.", ValidationErrorUnverifiable)
+		}
+	} else {
+		return token, parts, NewValidationError("signing method (alg) is unspecified.", ValidationErrorUnverifiable)
+	}
+
+	return token, parts, nil
+}
@@ -0,0 +1,101 @@
+package jwt
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+)
+
+// Implements the RSA family of signing methods signing methods
+// Expects *rsa.PrivateKey for signing and *rsa.PublicKey for validation
+type SigningMethodRSA struct {
+	Name string
+	Hash crypto.Hash
+}
+
+// Specific instances for RS256 and company
+var (
+	SigningMethodRS256 *SigningMethodRSA
+	SigningMethodRS384 *SigningMethodRSA
+	SigningMethodRS512 *SigningMethodRSA
+)
+
+func init() {
+	// RS256
+	SigningMethodRS256 = &SigningMethodRSA{"RS256", crypto.SHA256}
+	RegisterSigningMethod(SigningMethodRS256.Alg(), func() SigningMethod {
+		return SigningMethodRS256
+	})
+
+	// RS384
+	SigningMethodRS384 = &SigningMethodRSA{"RS384", crypto.SHA384}
+	RegisterSigningMethod(SigningMethodRS384.Alg(), func() SigningMethod {
+		return SigningMethodRS384
+	})
+
+	// RS512
+	SigningMethodRS512 = &SigningMethodRSA{"RS512", crypto.SHA512}
+	RegisterSigningMethod(SigningMethodRS512.Alg(), func() SigningMethod {
+		return SigningMethodRS512
+	})
+}
+
+func (m *SigningMethodRSA) Alg() string {
+	return m.Name
+}
+
+// Implements the Verify method from SigningMethod
+// For this signing method, must be an *rsa.PublicKey structure.
+func (m *SigningMethodRSA) Verify(signingString, signature string, key interface{}) error {
+	var err error
+
+	// Decode the signature
+	var sig []byte
+	if sig, err = DecodeSegment(signature); err != nil {
+		return err
+	}
+
+	var rsaKey *rsa.PublicKey
+	var ok bool
+
+	if rsaKey, ok = key.(*rsa.PublicKey); !ok {
+		return ErrInvalidKeyType
+	}
+
+	// Create hasher
+	if !m.Hash.Available() {
+		return ErrHashUnavailable
+	}
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	// Verify the signature
+	return rsa.VerifyPKCS1v15(rsaKey, m.Hash, hasher.Sum(nil), sig)
+}
+
+// Implements the Sign method from SigningMethod
+// For this signing method, must be an *rsa.PrivateKey structure.
+func (m *SigningMethodRSA) Sign(signingString string, key interface{}) (string, error) {
+	var rsaKey *rsa.PrivateKey
+	var ok bool
+
+	// Validate type of key
+	if rsaKey, ok = key.(*rsa.PrivateKey); !ok {
+		return "", ErrInvalidKey
+	}
+
+	// Create the hasher
+	if !m.Hash.Available() {
+		return "", ErrHashUnavailable
+	}
+
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	// Sign the string and return the encoded bytes
+	if sigBytes, err := rsa.SignPKCS1v15(rand.Reader, rsaKey, m.Hash, hasher.Sum(nil)); err == nil {
+		return EncodeSegment(sigBytes), nil
+	} else {
+		return "", err
+	}
+}
@@ -0,0 +1,142 @@
+// +build go1.4
+
+package jwt
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+)
+
+// Implements the RSAPSS family of signing methods signing methods
+type SigningMethodRSAPSS struct {
+	*SigningMethodRSA
+	Options *rsa.PSSOptions
+	// VerifyOptions is optional. If set overrides Options for rsa.VerifyPPS.
+	// Used to accept tokens signed with rsa.PSSSaltLengthAuto, what doesn't follow
+	// https://tools.ietf.org/html/rfc7518#section-3.5 but was used previously.
+	// See https://github.com/dgrijalva/jwt-go/issues/285#issuecomment-437451244 for details.
+	VerifyOptions *rsa.PSSOptions
+}
+
+// Specific instances for RS/PS and company.
+var (
+	SigningMethodPS256 *SigningMethodRSAPSS
+	SigningMethodPS384 *SigningMethodRSAPSS
+	SigningMethodPS512 *SigningMethodRSAPSS
+)
+
+func init() {
+	// PS256
+	SigningMethodPS256 = &SigningMethodRSAPSS{
+		SigningMethodRSA: &SigningMethodRSA{
+			Name: "PS256",
+			Hash: crypto.SHA256,
+		},
+		Options: &rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthEqualsHash,
+		},
+		VerifyOptions: &rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthAuto,
+		},
+	}
+	RegisterSigningMethod(SigningMethodPS256.Alg(), func() SigningMethod {
+		return SigningMethodPS256
+	})
+
+	// PS384
+	SigningMethodPS384 = &SigningMethodRSAPSS{
+		SigningMethodRSA: &SigningMethodRSA{
+			Name: "PS384",
+			Hash: crypto.SHA384,
+		},
+		Options: &rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthEqualsHash,
+		},
+		VerifyOptions: &rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthAuto,
+		},
+	}
+	RegisterSigningMethod(SigningMethodPS384.Alg(), func() SigningMethod {
+		return SigningMethodPS384
+	})
+
+	// PS512
+	SigningMethodPS512 = &SigningMethodRSAPSS{
+		SigningMethodRSA: &SigningMethodRSA{
+			Name: "PS512",
+			Hash: crypto.SHA512,
+		},
+		Options: &rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthEqualsHash,
+		},
+		VerifyOptions: &rsa.PSSOptions{
+			SaltLength: rsa.PSSSaltLengthAuto,
+		},
+	}
+	RegisterSigningMethod(SigningMethodPS512.Alg(), func() SigningMethod {
+		return SigningMethodPS512
+	})
+}
+
+// Implements the Verify method from SigningMethod
+// For this verify method, key must be an rsa.PublicKey struct
+func (m *SigningMethodRSAPSS) Verify(signingString, signature string, key interface{}) error {
+	var err error
+
+	// Decode the signature
+	var sig []byte
+	if sig, err = DecodeSegment(signature); err != nil {
+		return err
+	}
+
+	var rsaKey *rsa.PublicKey
+	switch k := key.(type) {
+	case *rsa.PublicKey:
+		rsaKey = k
+	default:
+		return ErrInvalidKey
+	}
+
+	// Create hasher
+	if !m.Hash.Available() {
+		return ErrHashUnavailable
+	}
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	opts := m.Options
+	if m.VerifyOptions != nil {
+		opts = m.VerifyOptions
+	}
+
+	return rsa.VerifyPSS(rsaKey, m.Hash, hasher.Sum(nil), sig, opts)
+}
+
+// Implements the Sign method from SigningMethod
+// For this signing method, key must be an rsa.PrivateKey struct
+func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (string, error) {
+	var rsaKey *rsa.PrivateKey
+
+	switch k := key.(type) {
+	case *rsa.PrivateKey:
+		rsaKey = k
+	default:
+		return "", ErrInvalidKeyType
+	}
+
+	// Create the hasher
+	if !m.Hash.Available() {
+		return "", ErrHashUnavailable
+	}
+
+	hasher := m.Hash.New()
+	hasher.Write([]byte(signingString))
+
+	// Sign the string and return the encoded bytes
+	if sigBytes, err := rsa.SignPSS(rand.Reader, rsaKey, m.Hash, hasher.Sum(nil), m.Options); err == nil {
+		return EncodeSegment(sigBytes), nil
+	} else {
+		return "", err
+	}
+}
@@ -0,0 +1,101 @@
+package jwt
+
+import (
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+)
+
+var (
+	ErrKeyMustBePEMEncoded = errors.New("Invalid Key: Key must be a PEM encoded PKCS1 or PKCS8 key")
+	ErrNotRSAPrivateKey    = errors.New("Key is not a valid RSA private key")
+	ErrNotRSAPublicKey     = errors.New("Key is not a valid RSA public key")
+)
+
+// Parse PEM encoded PKCS1 or PKCS8 private key
+func ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKCS1PrivateKey(block.Bytes); err != nil {
+		if parsedKey, err = x509.ParsePKCS8PrivateKey(block.Bytes); err != nil {
+			return nil, err
+		}
+	}
+
+	var pkey *rsa.PrivateKey
+	var ok bool
+	if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
+		return nil, ErrNotRSAPrivateKey
+	}
+
+	return pkey, nil
+}
+
+// Parse PEM encoded PKCS1 or PKCS8 private key protected with password
+func ParseRSAPrivateKeyFromPEMWithPassword(key []byte, password string) (*rsa.PrivateKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	var parsedKey interface{}
+
+	var blockDecrypted []byte
+	if blockDecrypted, err = x509.DecryptPEMBlock(block, []byte(password)); err != nil {
+		return nil, err
+	}
+
+	if parsedKey, err = x509.ParsePKCS1PrivateKey(blockDecrypted); err != nil {
+		if parsedKey, err = x509.ParsePKCS8PrivateKey(blockDecrypted); err != nil {
+			return nil, err
+		}
+	}
+
+	var pkey *rsa.PrivateKey
+	var ok bool
+	if pkey, ok = parsedKey.(*rsa.PrivateKey); !ok {
+		return nil, ErrNotRSAPrivateKey
+	}
+
+	return pkey, nil
+}
+
+// Parse PEM encoded PKCS1 or PKCS8 public key
+func ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error) {
+	var err error
+
+	// Parse PEM block
+	var block *pem.Block
+	if block, _ = pem.Decode(key); block == nil {
+		return nil, ErrKeyMustBePEMEncoded
+	}
+
+	// Parse the key
+	var parsedKey interface{}
+	if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
+		if cert, err := x509.ParseCertificate(block.Bytes); err == nil {
+			parsedKey = cert.PublicKey
+		} else {
+			return nil, err
+		}
+	}
+
+	var pkey *rsa.PublicKey
+	var ok bool
+	if pkey, ok = parsedKey.(*rsa.PublicKey); !ok {
+		return nil, ErrNotRSAPublicKey
+	}
+
+	return pkey, nil
+}
@@ -0,0 +1,35 @@
+package jwt
+
+import (
+	"sync"
+)
+
+var signingMethods = map[string]func() SigningMethod{}
+var signingMethodLock = new(sync.RWMutex)
+
+// Implement SigningMethod to add new methods for signing or verifying tokens.
+type SigningMethod interface {
+	Verify(signingString, signature string, key interface{}) error // Returns nil if signature is valid
+	Sign(signingString string, key interface{}) (string, error)    // Returns encoded signature or error
+	Alg() string                                                   // returns the alg identifier for this method (example: 'HS256')
+}
+
+// Register the "alg" name and a factory function for signing method.
+// This is typically done during init() in the method's implementation
+func RegisterSigningMethod(alg string, f func() SigningMethod) {
+	signingMethodLock.Lock()
+	defer signingMethodLock.Unlock()
+
+	signingMethods[alg] = f
+}
+
+// Get a signing method from an "alg" string
+func GetSigningMethod(alg string) (method SigningMethod) {
+	signingMethodLock.RLock()
+	defer signingMethodLock.RUnlock()
+
+	if methodF, ok := signingMethods[alg]; ok {
+		method = methodF()
+	}
+	return
+}
@@ -0,0 +1,108 @@
+package jwt
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+	"time"
+)
+
+// TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time).
+// You can override it to use another time value.  This is useful for testing or if your
+// server uses a different time zone than your tokens.
+var TimeFunc = time.Now
+
+// Parse methods use this callback function to supply
+// the key for verification.  The function receives the parsed,
+// but unverified Token.  This allows you to use properties in the
+// Header of the token (such as `kid`) to identify which key to use.
+type Keyfunc func(*Token) (interface{}, error)
+
+// A JWT Token.  Different fields will be used depending on whether you're
+// creating or parsing/verifying a token.
+type Token struct {
+	Raw       string                 // The raw token.  Populated when you Parse a token
+	Method    SigningMethod          // The signing method used or to be used
+	Header    map[string]interface{} // The first segment of the token
+	Claims    Claims                 // The second segment of the token
+	Signature string                 // The third segment of the token.  Populated when you Parse a token
+	Valid     bool                   // Is the token valid?  Populated when you Parse/Verify a token
+}
+
+// Create a new Token.  Takes a signing method
+func New(method SigningMethod) *Token {
+	return NewWithClaims(method, MapClaims{})
+}
+
+func NewWithClaims(method SigningMethod, claims Claims) *Token {
+	return &Token{
+		Header: map[string]interface{}{
+			"typ": "JWT",
+			"alg": method.Alg(),
+		},
+		Claims: claims,
+		Method: method,
+	}
+}
+
+// Get the complete, signed token
+func (t *Token) SignedString(key interface{}) (string, error) {
+	var sig, sstr string
+	var err error
+	if sstr, err = t.SigningString(); err != nil {
+		return "", err
+	}
+	if sig, err = t.Method.Sign(sstr, key); err != nil {
+		return "", err
+	}
+	return strings.Join([]string{sstr, sig}, "."), nil
+}
+
+// Generate the signing string.  This is the
+// most expensive part of the whole deal.  Unless you
+// need this for something special, just go straight for
+// the SignedString.
+func (t *Token) SigningString() (string, error) {
+	var err error
+	parts := make([]string, 2)
+	for i, _ := range parts {
+		var jsonValue []byte
+		if i == 0 {
+			if jsonValue, err = json.Marshal(t.Header); err != nil {
+				return "", err
+			}
+		} else {
+			if jsonValue, err = json.Marshal(t.Claims); err != nil {
+				return "", err
+			}
+		}
+
+		parts[i] = EncodeSegment(jsonValue)
+	}
+	return strings.Join(parts, "."), nil
+}
+
+// Parse, validate, and return a token.
+// keyFunc will receive the parsed token and should return the key for validating.
+// If everything is kosher, err will be nil
+func Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
+	return new(Parser).Parse(tokenString, keyFunc)
+}
+
+func ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
+	return new(Parser).ParseWithClaims(tokenString, claims, keyFunc)
+}
+
+// Encode JWT specific base64url encoding with padding stripped
+func EncodeSegment(seg []byte) string {
+	return strings.TrimRight(base64.URLEncoding.EncodeToString(seg), "=")
+}
+
+// Decode JWT specific base64url encoding with padding stripped
+func DecodeSegment(seg string) ([]byte, error) {
+	if l := len(seg) % 4; l > 0 {
+		seg += strings.Repeat("=", 4-l)
+	}
+
+	return base64.URLEncoding.DecodeString(seg)
+}
@@ -0,0 +1,8 @@
+# This is the official list of gorilla/mux authors for copyright purposes.
+#
+# Please keep the list sorted.
+
+Google LLC (https://opensource.google.com/)
+Kamil Kisielk <kamil@kamilkisiel.net>
+Matt Silverlock <matt@eatsleeprepeat.net>
+Rodrigo Moraes (https://github.com/moraes)
@@ -0,0 +1,27 @@
+Copyright (c) 2012-2018 The Gorilla Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+	 * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+	 * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+	 * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
@@ -0,0 +1,805 @@
+# gorilla/mux
+
+[![GoDoc](https://godoc.org/github.com/gorilla/mux?status.svg)](https://godoc.org/github.com/gorilla/mux)
+[![CircleCI](https://circleci.com/gh/gorilla/mux.svg?style=svg)](https://circleci.com/gh/gorilla/mux)
+[![Sourcegraph](https://sourcegraph.com/github.com/gorilla/mux/-/badge.svg)](https://sourcegraph.com/github.com/gorilla/mux?badge)
+
+![Gorilla Logo](https://cloud-cdn.questionable.services/gorilla-icon-64.png)
+
+https://www.gorillatoolkit.org/pkg/mux
+
+Package `gorilla/mux` implements a request router and dispatcher for matching incoming requests to
+their respective handler.
+
+The name mux stands for "HTTP request multiplexer". Like the standard `http.ServeMux`, `mux.Router` matches incoming requests against a list of registered routes and calls a handler for the route that matches the URL or other conditions. The main features are:
+
+* It implements the `http.Handler` interface so it is compatible with the standard `http.ServeMux`.
+* Requests can be matched based on URL host, path, path prefix, schemes, header and query values, HTTP methods or using custom matchers.
+* URL hosts, paths and query values can have variables with an optional regular expression.
+* Registered URLs can be built, or "reversed", which helps maintaining references to resources.
+* Routes can be used as subrouters: nested routes are only tested if the parent route matches. This is useful to define groups of routes that share common conditions like a host, a path prefix or other repeated attributes. As a bonus, this optimizes request matching.
+
+---
+
+* [Install](#install)
+* [Examples](#examples)
+* [Matching Routes](#matching-routes)
+* [Static Files](#static-files)
+* [Serving Single Page Applications](#serving-single-page-applications) (e.g. React, Vue, Ember.js, etc.)
+* [Registered URLs](#registered-urls)
+* [Walking Routes](#walking-routes)
+* [Graceful Shutdown](#graceful-shutdown)
+* [Middleware](#middleware)
+* [Handling CORS Requests](#handling-cors-requests)
+* [Testing Handlers](#testing-handlers)
+* [Full Example](#full-example)
+
+---
+
+## Install
+
+With a [correctly configured](https://golang.org/doc/install#testing) Go toolchain:
+
+```sh
+go get -u github.com/gorilla/mux
+```
+
+## Examples
+
+Let's start registering a couple of URL paths and handlers:
+
+```go
+func main() {
+    r := mux.NewRouter()
+    r.HandleFunc("/", HomeHandler)
+    r.HandleFunc("/products", ProductsHandler)
+    r.HandleFunc("/articles", ArticlesHandler)
+    http.Handle("/", r)
+}
+```
+
+Here we register three routes mapping URL paths to handlers. This is equivalent to how `http.HandleFunc()` works: if an incoming request URL matches one of the paths, the corresponding handler is called passing (`http.ResponseWriter`, `*http.Request`) as parameters.
+
+Paths can have variables. They are defined using the format `{name}` or `{name:pattern}`. If a regular expression pattern is not defined, the matched variable will be anything until the next slash. For example:
+
+```go
+r := mux.NewRouter()
+r.HandleFunc("/products/{key}", ProductHandler)
+r.HandleFunc("/articles/{category}/", ArticlesCategoryHandler)
+r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler)
+```
+
+The names are used to create a map of route variables which can be retrieved calling `mux.Vars()`:
+
+```go
+func ArticlesCategoryHandler(w http.ResponseWriter, r *http.Request) {
+    vars := mux.Vars(r)
+    w.WriteHeader(http.StatusOK)
+    fmt.Fprintf(w, "Category: %v\n", vars["category"])
+}
+```
+
+And this is all you need to know about the basic usage. More advanced options are explained below.
+
+### Matching Routes
+
+Routes can also be restricted to a domain or subdomain. Just define a host pattern to be matched. They can also have variables:
+
+```go
+r := mux.NewRouter()
+// Only matches if domain is "www.example.com".
+r.Host("www.example.com")
+// Matches a dynamic subdomain.
+r.Host("{subdomain:[a-z]+}.example.com")
+```
+
+There are several other matchers that can be added. To match path prefixes:
+
+```go
+r.PathPrefix("/products/")
+```
+
+...or HTTP methods:
+
+```go
+r.Methods("GET", "POST")
+```
+
+...or URL schemes:
+
+```go
+r.Schemes("https")
+```
+
+...or header values:
+
+```go
+r.Headers("X-Requested-With", "XMLHttpRequest")
+```
+
+...or query values:
+
+```go
+r.Queries("key", "value")
+```
+
+...or to use a custom matcher function:
+
+```go
+r.MatcherFunc(func(r *http.Request, rm *RouteMatch) bool {
+    return r.ProtoMajor == 0
+})
+```
+
+...and finally, it is possible to combine several matchers in a single route:
+
+```go
+r.HandleFunc("/products", ProductsHandler).
+  Host("www.example.com").
+  Methods("GET").
+  Schemes("http")
+```
+
+Routes are tested in the order they were added to the router. If two routes match, the first one wins:
+
+```go
+r := mux.NewRouter()
+r.HandleFunc("/specific", specificHandler)
+r.PathPrefix("/").Handler(catchAllHandler)
+```
+
+Setting the same matching conditions again and again can be boring, so we have a way to group several routes that share the same requirements. We call it "subrouting".
+
+For example, let's say we have several URLs that should only match when the host is `www.example.com`. Create a route for that host and get a "subrouter" from it:
+
+```go
+r := mux.NewRouter()
+s := r.Host("www.example.com").Subrouter()
+```
+
+Then register routes in the subrouter:
+
+```go
+s.HandleFunc("/products/", ProductsHandler)
+s.HandleFunc("/products/{key}", ProductHandler)
+s.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler)
+```
+
+The three URL paths we registered above will only be tested if the domain is `www.example.com`, because the subrouter is tested first. This is not only convenient, but also optimizes request matching. You can create subrouters combining any attribute matchers accepted by a route.
+
+Subrouters can be used to create domain or path "namespaces": you define subrouters in a central place and then parts of the app can register its paths relatively to a given subrouter.
+
+There's one more thing about subroutes. When a subrouter has a path prefix, the inner routes use it as base for their paths:
+
+```go
+r := mux.NewRouter()
+s := r.PathPrefix("/products").Subrouter()
+// "/products/"
+s.HandleFunc("/", ProductsHandler)
+// "/products/{key}/"
+s.HandleFunc("/{key}/", ProductHandler)
+// "/products/{key}/details"
+s.HandleFunc("/{key}/details", ProductDetailsHandler)
+```
+
+
+### Static Files
+
+Note that the path provided to `PathPrefix()` represents a "wildcard": calling
+`PathPrefix("/static/").Handler(...)` means that the handler will be passed any
+request that matches "/static/\*". This makes it easy to serve static files with mux:
+
+```go
+func main() {
+    var dir string
+
+    flag.StringVar(&dir, "dir", ".", "the directory to serve files from. Defaults to the current dir")
+    flag.Parse()
+    r := mux.NewRouter()
+
+    // This will serve files under http://localhost:8000/static/<filename>
+    r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir(dir))))
+
+    srv := &http.Server{
+        Handler:      r,
+        Addr:         "127.0.0.1:8000",
+        // Good practice: enforce timeouts for servers you create!
+        WriteTimeout: 15 * time.Second,
+        ReadTimeout:  15 * time.Second,
+    }
+
+    log.Fatal(srv.ListenAndServe())
+}
+```
+
+### Serving Single Page Applications
+
+Most of the time it makes sense to serve your SPA on a separate web server from your API,
+but sometimes it's desirable to serve them both from one place. It's possible to write a simple
+handler for serving your SPA (for use with React Router's [BrowserRouter](https://reacttraining.com/react-router/web/api/BrowserRouter) for example), and leverage
+mux's powerful routing for your API endpoints.
+
+```go
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/gorilla/mux"
+)
+
+// spaHandler implements the http.Handler interface, so we can use it
+// to respond to HTTP requests. The path to the static directory and
+// path to the index file within that static directory are used to
+// serve the SPA in the given static directory.
+type spaHandler struct {
+	staticPath string
+	indexPath  string
+}
+
+// ServeHTTP inspects the URL path to locate a file within the static dir
+// on the SPA handler. If a file is found, it will be served. If not, the
+// file located at the index path on the SPA handler will be served. This
+// is suitable behavior for serving an SPA (single page application).
+func (h spaHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+    // get the absolute path to prevent directory traversal
+	path, err := filepath.Abs(r.URL.Path)
+	if err != nil {
+        // if we failed to get the absolute path respond with a 400 bad request
+        // and stop
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+    // prepend the path with the path to the static directory
+	path = filepath.Join(h.staticPath, path)
+
+    // check whether a file exists at the given path
+	_, err = os.Stat(path)
+	if os.IsNotExist(err) {
+		// file does not exist, serve index.html
+		http.ServeFile(w, r, filepath.Join(h.staticPath, h.indexPath))
+		return
+	} else if err != nil {
+        // if we got an error (that wasn't that the file doesn't exist) stating the
+        // file, return a 500 internal server error and stop
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+    // otherwise, use http.FileServer to serve the static dir
+	http.FileServer(http.Dir(h.staticPath)).ServeHTTP(w, r)
+}
+
+func main() {
+	router := mux.NewRouter()
+
+	router.HandleFunc("/api/health", func(w http.ResponseWriter, r *http.Request) {
+		// an example API handler
+		json.NewEncoder(w).Encode(map[string]bool{"ok": true})
+	})
+
+	spa := spaHandler{staticPath: "build", indexPath: "index.html"}
+	router.PathPrefix("/").Handler(spa)
+
+	srv := &http.Server{
+		Handler: router,
+		Addr:    "127.0.0.1:8000",
+		// Good practice: enforce timeouts for servers you create!
+		WriteTimeout: 15 * time.Second,
+		ReadTimeout:  15 * time.Second,
+	}
+
+	log.Fatal(srv.ListenAndServe())
+}
+```
+
+### Registered URLs
+
+Now let's see how to build registered URLs.
+
+Routes can be named. All routes that define a name can have their URLs built, or "reversed". We define a name calling `Name()` on a route. For example:
+
+```go
+r := mux.NewRouter()
+r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler).
+  Name("article")
+```
+
+To build a URL, get the route and call the `URL()` method, passing a sequence of key/value pairs for the route variables. For the previous route, we would do:
+
+```go
+url, err := r.Get("article").URL("category", "technology", "id", "42")
+```
+
+...and the result will be a `url.URL` with the following path:
+
+```
+"/articles/technology/42"
+```
+
+This also works for host and query value variables:
+
+```go
+r := mux.NewRouter()
+r.Host("{subdomain}.example.com").
+  Path("/articles/{category}/{id:[0-9]+}").
+  Queries("filter", "{filter}").
+  HandlerFunc(ArticleHandler).
+  Name("article")
+
+// url.String() will be "http://news.example.com/articles/technology/42?filter=gorilla"
+url, err := r.Get("article").URL("subdomain", "news",
+                                 "category", "technology",
+                                 "id", "42",
+                                 "filter", "gorilla")
+```
+
+All variables defined in the route are required, and their values must conform to the corresponding patterns. These requirements guarantee that a generated URL will always match a registered route -- the only exception is for explicitly defined "build-only" routes which never match.
+
+Regex support also exists for matching Headers within a route. For example, we could do:
+
+```go
+r.HeadersRegexp("Content-Type", "application/(text|json)")
+```
+
+...and the route will match both requests with a Content-Type of `application/json` as well as `application/text`
+
+There's also a way to build only the URL host or path for a route: use the methods `URLHost()` or `URLPath()` instead. For the previous route, we would do:
+
+```go
+// "http://news.example.com/"
+host, err := r.Get("article").URLHost("subdomain", "news")
+
+// "/articles/technology/42"
+path, err := r.Get("article").URLPath("category", "technology", "id", "42")
+```
+
+And if you use subrouters, host and path defined separately can be built as well:
+
+```go
+r := mux.NewRouter()
+s := r.Host("{subdomain}.example.com").Subrouter()
+s.Path("/articles/{category}/{id:[0-9]+}").
+  HandlerFunc(ArticleHandler).
+  Name("article")
+
+// "http://news.example.com/articles/technology/42"
+url, err := r.Get("article").URL("subdomain", "news",
+                                 "category", "technology",
+                                 "id", "42")
+```
+
+### Walking Routes
+
+The `Walk` function on `mux.Router` can be used to visit all of the routes that are registered on a router. For example,
+the following prints all of the registered routes:
+
+```go
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/gorilla/mux"
+)
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	return
+}
+
+func main() {
+	r := mux.NewRouter()
+	r.HandleFunc("/", handler)
+	r.HandleFunc("/products", handler).Methods("POST")
+	r.HandleFunc("/articles", handler).Methods("GET")
+	r.HandleFunc("/articles/{id}", handler).Methods("GET", "PUT")
+	r.HandleFunc("/authors", handler).Queries("surname", "{surname}")
+	err := r.Walk(func(route *mux.Route, router *mux.Router, ancestors []*mux.Route) error {
+		pathTemplate, err := route.GetPathTemplate()
+		if err == nil {
+			fmt.Println("ROUTE:", pathTemplate)
+		}
+		pathRegexp, err := route.GetPathRegexp()
+		if err == nil {
+			fmt.Println("Path regexp:", pathRegexp)
+		}
+		queriesTemplates, err := route.GetQueriesTemplates()
+		if err == nil {
+			fmt.Println("Queries templates:", strings.Join(queriesTemplates, ","))
+		}
+		queriesRegexps, err := route.GetQueriesRegexp()
+		if err == nil {
+			fmt.Println("Queries regexps:", strings.Join(queriesRegexps, ","))
+		}
+		methods, err := route.GetMethods()
+		if err == nil {
+			fmt.Println("Methods:", strings.Join(methods, ","))
+		}
+		fmt.Println()
+		return nil
+	})
+
+	if err != nil {
+		fmt.Println(err)
+	}
+
+	http.Handle("/", r)
+}
+```
+
+### Graceful Shutdown
+
+Go 1.8 introduced the ability to [gracefully shutdown](https://golang.org/doc/go1.8#http_shutdown) a `*http.Server`. Here's how to do that alongside `mux`:
+
+```go
+package main
+
+import (
+    "context"
+    "flag"
+    "log"
+    "net/http"
+    "os"
+    "os/signal"
+    "time"
+
+    "github.com/gorilla/mux"
+)
+
+func main() {
+    var wait time.Duration
+    flag.DurationVar(&wait, "graceful-timeout", time.Second * 15, "the duration for which the server gracefully wait for existing connections to finish - e.g. 15s or 1m")
+    flag.Parse()
+
+    r := mux.NewRouter()
+    // Add your routes as needed
+
+    srv := &http.Server{
+        Addr:         "0.0.0.0:8080",
+        // Good practice to set timeouts to avoid Slowloris attacks.
+        WriteTimeout: time.Second * 15,
+        ReadTimeout:  time.Second * 15,
+        IdleTimeout:  time.Second * 60,
+        Handler: r, // Pass our instance of gorilla/mux in.
+    }
+
+    // Run our server in a goroutine so that it doesn't block.
+    go func() {
+        if err := srv.ListenAndServe(); err != nil {
+            log.Println(err)
+        }
+    }()
+
+    c := make(chan os.Signal, 1)
+    // We'll accept graceful shutdowns when quit via SIGINT (Ctrl+C)
+    // SIGKILL, SIGQUIT or SIGTERM (Ctrl+/) will not be caught.
+    signal.Notify(c, os.Interrupt)
+
+    // Block until we receive our signal.
+    <-c
+
+    // Create a deadline to wait for.
+    ctx, cancel := context.WithTimeout(context.Background(), wait)
+    defer cancel()
+    // Doesn't block if no connections, but will otherwise wait
+    // until the timeout deadline.
+    srv.Shutdown(ctx)
+    // Optionally, you could run srv.Shutdown in a goroutine and block on
+    // <-ctx.Done() if your application should wait for other services
+    // to finalize based on context cancellation.
+    log.Println("shutting down")
+    os.Exit(0)
+}
+```
+
+### Middleware
+
+Mux supports the addition of middlewares to a [Router](https://godoc.org/github.com/gorilla/mux#Router), which are executed in the order they are added if a match is found, including its subrouters.
+Middlewares are (typically) small pieces of code which take one request, do something with it, and pass it down to another middleware or the final handler. Some common use cases for middleware are request logging, header manipulation, or `ResponseWriter` hijacking.
+
+Mux middlewares are defined using the de facto standard type:
+
+```go
+type MiddlewareFunc func(http.Handler) http.Handler
+```
+
+Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed to it, and then calls the handler passed as parameter to the MiddlewareFunc. This takes advantage of closures being able access variables from the context where they are created, while retaining the signature enforced by the receivers.
+
+A very basic middleware which logs the URI of the request being handled could be written as:
+
+```go
+func loggingMiddleware(next http.Handler) http.Handler {
+    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+        // Do stuff here
+        log.Println(r.RequestURI)
+        // Call the next handler, which can be another middleware in the chain, or the final handler.
+        next.ServeHTTP(w, r)
+    })
+}
+```
+
+Middlewares can be added to a router using `Router.Use()`:
+
+```go
+r := mux.NewRouter()
+r.HandleFunc("/", handler)
+r.Use(loggingMiddleware)
+```
+
+A more complex authentication middleware, which maps session token to users, could be written as:
+
+```go
+// Define our struct
+type authenticationMiddleware struct {
+	tokenUsers map[string]string
+}
+
+// Initialize it somewhere
+func (amw *authenticationMiddleware) Populate() {
+	amw.tokenUsers["00000000"] = "user0"
+	amw.tokenUsers["aaaaaaaa"] = "userA"
+	amw.tokenUsers["05f717e5"] = "randomUser"
+	amw.tokenUsers["deadbeef"] = "user0"
+}
+
+// Middleware function, which will be called for each request
+func (amw *authenticationMiddleware) Middleware(next http.Handler) http.Handler {
+    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+        token := r.Header.Get("X-Session-Token")
+
+        if user, found := amw.tokenUsers[token]; found {
+        	// We found the token in our map
+        	log.Printf("Authenticated user %s\n", user)
+        	// Pass down the request to the next middleware (or final handler)
+        	next.ServeHTTP(w, r)
+        } else {
+        	// Write an error and stop the handler chain
+        	http.Error(w, "Forbidden", http.StatusForbidden)
+        }
+    })
+}
+```
+
+```go
+r := mux.NewRouter()
+r.HandleFunc("/", handler)
+
+amw := authenticationMiddleware{}
+amw.Populate()
+
+r.Use(amw.Middleware)
+```
+
+Note: The handler chain will be stopped if your middleware doesn't call `next.ServeHTTP()` with the corresponding parameters. This can be used to abort a request if the middleware writer wants to. Middlewares _should_ write to `ResponseWriter` if they _are_ going to terminate the request, and they _should not_ write to `ResponseWriter` if they _are not_ going to terminate it.
+
+### Handling CORS Requests
+
+[CORSMethodMiddleware](https://godoc.org/github.com/gorilla/mux#CORSMethodMiddleware) intends to make it easier to strictly set the `Access-Control-Allow-Methods` response header.
+
+* You will still need to use your own CORS handler to set the other CORS headers such as `Access-Control-Allow-Origin`
+* The middleware will set the `Access-Control-Allow-Methods` header to all the method matchers (e.g. `r.Methods(http.MethodGet, http.MethodPut, http.MethodOptions)` -> `Access-Control-Allow-Methods: GET,PUT,OPTIONS`) on a route
+* If you do not specify any methods, then:
+> _Important_: there must be an `OPTIONS` method matcher for the middleware to set the headers.
+
+Here is an example of using `CORSMethodMiddleware` along with a custom `OPTIONS` handler to set all the required CORS headers:
+
+```go
+package main
+
+import (
+	"net/http"
+	"github.com/gorilla/mux"
+)
+
+func main() {
+    r := mux.NewRouter()
+
+    // IMPORTANT: you must specify an OPTIONS method matcher for the middleware to set CORS headers
+    r.HandleFunc("/foo", fooHandler).Methods(http.MethodGet, http.MethodPut, http.MethodPatch, http.MethodOptions)
+    r.Use(mux.CORSMethodMiddleware(r))
+    
+    http.ListenAndServe(":8080", r)
+}
+
+func fooHandler(w http.ResponseWriter, r *http.Request) {
+    w.Header().Set("Access-Control-Allow-Origin", "*")
+    if r.Method == http.MethodOptions {
+        return
+    }
+
+    w.Write([]byte("foo"))
+}
+```
+
+And an request to `/foo` using something like:
+
+```bash
+curl localhost:8080/foo -v
+```
+
+Would look like:
+
+```bash
+*   Trying ::1...
+* TCP_NODELAY set
+* Connected to localhost (::1) port 8080 (#0)
+> GET /foo HTTP/1.1
+> Host: localhost:8080
+> User-Agent: curl/7.59.0
+> Accept: */*
+> 
+< HTTP/1.1 200 OK
+< Access-Control-Allow-Methods: GET,PUT,PATCH,OPTIONS
+< Access-Control-Allow-Origin: *
+< Date: Fri, 28 Jun 2019 20:13:30 GMT
+< Content-Length: 3
+< Content-Type: text/plain; charset=utf-8
+< 
+* Connection #0 to host localhost left intact
+foo
+```
+
+### Testing Handlers
+
+Testing handlers in a Go web application is straightforward, and _mux_ doesn't complicate this any further. Given two files: `endpoints.go` and `endpoints_test.go`, here's how we'd test an application using _mux_.
+
+First, our simple HTTP handler:
+
+```go
+// endpoints.go
+package main
+
+func HealthCheckHandler(w http.ResponseWriter, r *http.Request) {
+    // A very simple health check.
+    w.Header().Set("Content-Type", "application/json")
+    w.WriteHeader(http.StatusOK)
+
+    // In the future we could report back on the status of our DB, or our cache
+    // (e.g. Redis) by performing a simple PING, and include them in the response.
+    io.WriteString(w, `{"alive": true}`)
+}
+
+func main() {
+    r := mux.NewRouter()
+    r.HandleFunc("/health", HealthCheckHandler)
+
+    log.Fatal(http.ListenAndServe("localhost:8080", r))
+}
+```
+
+Our test code:
+
+```go
+// endpoints_test.go
+package main
+
+import (
+    "net/http"
+    "net/http/httptest"
+    "testing"
+)
+
+func TestHealthCheckHandler(t *testing.T) {
+    // Create a request to pass to our handler. We don't have any query parameters for now, so we'll
+    // pass 'nil' as the third parameter.
+    req, err := http.NewRequest("GET", "/health", nil)
+    if err != nil {
+        t.Fatal(err)
+    }
+
+    // We create a ResponseRecorder (which satisfies http.ResponseWriter) to record the response.
+    rr := httptest.NewRecorder()
+    handler := http.HandlerFunc(HealthCheckHandler)
+
+    // Our handlers satisfy http.Handler, so we can call their ServeHTTP method
+    // directly and pass in our Request and ResponseRecorder.
+    handler.ServeHTTP(rr, req)
+
+    // Check the status code is what we expect.
+    if status := rr.Code; status != http.StatusOK {
+        t.Errorf("handler returned wrong status code: got %v want %v",
+            status, http.StatusOK)
+    }
+
+    // Check the response body is what we expect.
+    expected := `{"alive": true}`
+    if rr.Body.String() != expected {
+        t.Errorf("handler returned unexpected body: got %v want %v",
+            rr.Body.String(), expected)
+    }
+}
+```
+
+In the case that our routes have [variables](#examples), we can pass those in the request. We could write
+[table-driven tests](https://dave.cheney.net/2013/06/09/writing-table-driven-tests-in-go) to test multiple
+possible route variables as needed.
+
+```go
+// endpoints.go
+func main() {
+    r := mux.NewRouter()
+    // A route with a route variable:
+    r.HandleFunc("/metrics/{type}", MetricsHandler)
+
+    log.Fatal(http.ListenAndServe("localhost:8080", r))
+}
+```
+
+Our test file, with a table-driven test of `routeVariables`:
+
+```go
+// endpoints_test.go
+func TestMetricsHandler(t *testing.T) {
+    tt := []struct{
+        routeVariable string
+        shouldPass bool
+    }{
+        {"goroutines", true},
+        {"heap", true},
+        {"counters", true},
+        {"queries", true},
+        {"adhadaeqm3k", false},
+    }
+
+    for _, tc := range tt {
+        path := fmt.Sprintf("/metrics/%s", tc.routeVariable)
+        req, err := http.NewRequest("GET", path, nil)
+        if err != nil {
+            t.Fatal(err)
+        }
+
+        rr := httptest.NewRecorder()
+	
+	// Need to create a router that we can pass the request through so that the vars will be added to the context
+	router := mux.NewRouter()
+        router.HandleFunc("/metrics/{type}", MetricsHandler)
+        router.ServeHTTP(rr, req)
+
+        // In this case, our MetricsHandler returns a non-200 response
+        // for a route variable it doesn't know about.
+        if rr.Code == http.StatusOK && !tc.shouldPass {
+            t.Errorf("handler should have failed on routeVariable %s: got %v want %v",
+                tc.routeVariable, rr.Code, http.StatusOK)
+        }
+    }
+}
+```
+
+## Full Example
+
+Here's a complete, runnable example of a small `mux` based server:
+
+```go
+package main
+
+import (
+    "net/http"
+    "log"
+    "github.com/gorilla/mux"
+)
+
+func YourHandler(w http.ResponseWriter, r *http.Request) {
+    w.Write([]byte("Gorilla!\n"))
+}
+
+func main() {
+    r := mux.NewRouter()
+    // Routes consist of a path and a handler function.
+    r.HandleFunc("/", YourHandler)
+
+    // Bind to a port and pass our router in
+    log.Fatal(http.ListenAndServe(":8000", r))
+}
+```
+
+## License
+
+BSD licensed. See the LICENSE file for details.
@@ -0,0 +1,306 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package mux implements a request router and dispatcher.
+
+The name mux stands for "HTTP request multiplexer". Like the standard
+http.ServeMux, mux.Router matches incoming requests against a list of
+registered routes and calls a handler for the route that matches the URL
+or other conditions. The main features are:
+
+	* Requests can be matched based on URL host, path, path prefix, schemes,
+	  header and query values, HTTP methods or using custom matchers.
+	* URL hosts, paths and query values can have variables with an optional
+	  regular expression.
+	* Registered URLs can be built, or "reversed", which helps maintaining
+	  references to resources.
+	* Routes can be used as subrouters: nested routes are only tested if the
+	  parent route matches. This is useful to define groups of routes that
+	  share common conditions like a host, a path prefix or other repeated
+	  attributes. As a bonus, this optimizes request matching.
+	* It implements the http.Handler interface so it is compatible with the
+	  standard http.ServeMux.
+
+Let's start registering a couple of URL paths and handlers:
+
+	func main() {
+		r := mux.NewRouter()
+		r.HandleFunc("/", HomeHandler)
+		r.HandleFunc("/products", ProductsHandler)
+		r.HandleFunc("/articles", ArticlesHandler)
+		http.Handle("/", r)
+	}
+
+Here we register three routes mapping URL paths to handlers. This is
+equivalent to how http.HandleFunc() works: if an incoming request URL matches
+one of the paths, the corresponding handler is called passing
+(http.ResponseWriter, *http.Request) as parameters.
+
+Paths can have variables. They are defined using the format {name} or
+{name:pattern}. If a regular expression pattern is not defined, the matched
+variable will be anything until the next slash. For example:
+
+	r := mux.NewRouter()
+	r.HandleFunc("/products/{key}", ProductHandler)
+	r.HandleFunc("/articles/{category}/", ArticlesCategoryHandler)
+	r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler)
+
+Groups can be used inside patterns, as long as they are non-capturing (?:re). For example:
+
+	r.HandleFunc("/articles/{category}/{sort:(?:asc|desc|new)}", ArticlesCategoryHandler)
+
+The names are used to create a map of route variables which can be retrieved
+calling mux.Vars():
+
+	vars := mux.Vars(request)
+	category := vars["category"]
+
+Note that if any capturing groups are present, mux will panic() during parsing. To prevent
+this, convert any capturing groups to non-capturing, e.g. change "/{sort:(asc|desc)}" to
+"/{sort:(?:asc|desc)}". This is a change from prior versions which behaved unpredictably
+when capturing groups were present.
+
+And this is all you need to know about the basic usage. More advanced options
+are explained below.
+
+Routes can also be restricted to a domain or subdomain. Just define a host
+pattern to be matched. They can also have variables:
+
+	r := mux.NewRouter()
+	// Only matches if domain is "www.example.com".
+	r.Host("www.example.com")
+	// Matches a dynamic subdomain.
+	r.Host("{subdomain:[a-z]+}.domain.com")
+
+There are several other matchers that can be added. To match path prefixes:
+
+	r.PathPrefix("/products/")
+
+...or HTTP methods:
+
+	r.Methods("GET", "POST")
+
+...or URL schemes:
+
+	r.Schemes("https")
+
+...or header values:
+
+	r.Headers("X-Requested-With", "XMLHttpRequest")
+
+...or query values:
+
+	r.Queries("key", "value")
+
+...or to use a custom matcher function:
+
+	r.MatcherFunc(func(r *http.Request, rm *RouteMatch) bool {
+		return r.ProtoMajor == 0
+	})
+
+...and finally, it is possible to combine several matchers in a single route:
+
+	r.HandleFunc("/products", ProductsHandler).
+	  Host("www.example.com").
+	  Methods("GET").
+	  Schemes("http")
+
+Setting the same matching conditions again and again can be boring, so we have
+a way to group several routes that share the same requirements.
+We call it "subrouting".
+
+For example, let's say we have several URLs that should only match when the
+host is "www.example.com". Create a route for that host and get a "subrouter"
+from it:
+
+	r := mux.NewRouter()
+	s := r.Host("www.example.com").Subrouter()
+
+Then register routes in the subrouter:
+
+	s.HandleFunc("/products/", ProductsHandler)
+	s.HandleFunc("/products/{key}", ProductHandler)
+	s.HandleFunc("/articles/{category}/{id:[0-9]+}"), ArticleHandler)
+
+The three URL paths we registered above will only be tested if the domain is
+"www.example.com", because the subrouter is tested first. This is not
+only convenient, but also optimizes request matching. You can create
+subrouters combining any attribute matchers accepted by a route.
+
+Subrouters can be used to create domain or path "namespaces": you define
+subrouters in a central place and then parts of the app can register its
+paths relatively to a given subrouter.
+
+There's one more thing about subroutes. When a subrouter has a path prefix,
+the inner routes use it as base for their paths:
+
+	r := mux.NewRouter()
+	s := r.PathPrefix("/products").Subrouter()
+	// "/products/"
+	s.HandleFunc("/", ProductsHandler)
+	// "/products/{key}/"
+	s.HandleFunc("/{key}/", ProductHandler)
+	// "/products/{key}/details"
+	s.HandleFunc("/{key}/details", ProductDetailsHandler)
+
+Note that the path provided to PathPrefix() represents a "wildcard": calling
+PathPrefix("/static/").Handler(...) means that the handler will be passed any
+request that matches "/static/*". This makes it easy to serve static files with mux:
+
+	func main() {
+		var dir string
+
+		flag.StringVar(&dir, "dir", ".", "the directory to serve files from. Defaults to the current dir")
+		flag.Parse()
+		r := mux.NewRouter()
+
+		// This will serve files under http://localhost:8000/static/<filename>
+		r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir(dir))))
+
+		srv := &http.Server{
+			Handler:      r,
+			Addr:         "127.0.0.1:8000",
+			// Good practice: enforce timeouts for servers you create!
+			WriteTimeout: 15 * time.Second,
+			ReadTimeout:  15 * time.Second,
+		}
+
+		log.Fatal(srv.ListenAndServe())
+	}
+
+Now let's see how to build registered URLs.
+
+Routes can be named. All routes that define a name can have their URLs built,
+or "reversed". We define a name calling Name() on a route. For example:
+
+	r := mux.NewRouter()
+	r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler).
+	  Name("article")
+
+To build a URL, get the route and call the URL() method, passing a sequence of
+key/value pairs for the route variables. For the previous route, we would do:
+
+	url, err := r.Get("article").URL("category", "technology", "id", "42")
+
+...and the result will be a url.URL with the following path:
+
+	"/articles/technology/42"
+
+This also works for host and query value variables:
+
+	r := mux.NewRouter()
+	r.Host("{subdomain}.domain.com").
+	  Path("/articles/{category}/{id:[0-9]+}").
+	  Queries("filter", "{filter}").
+	  HandlerFunc(ArticleHandler).
+	  Name("article")
+
+	// url.String() will be "http://news.domain.com/articles/technology/42?filter=gorilla"
+	url, err := r.Get("article").URL("subdomain", "news",
+	                                 "category", "technology",
+	                                 "id", "42",
+	                                 "filter", "gorilla")
+
+All variables defined in the route are required, and their values must
+conform to the corresponding patterns. These requirements guarantee that a
+generated URL will always match a registered route -- the only exception is
+for explicitly defined "build-only" routes which never match.
+
+Regex support also exists for matching Headers within a route. For example, we could do:
+
+	r.HeadersRegexp("Content-Type", "application/(text|json)")
+
+...and the route will match both requests with a Content-Type of `application/json` as well as
+`application/text`
+
+There's also a way to build only the URL host or path for a route:
+use the methods URLHost() or URLPath() instead. For the previous route,
+we would do:
+
+	// "http://news.domain.com/"
+	host, err := r.Get("article").URLHost("subdomain", "news")
+
+	// "/articles/technology/42"
+	path, err := r.Get("article").URLPath("category", "technology", "id", "42")
+
+And if you use subrouters, host and path defined separately can be built
+as well:
+
+	r := mux.NewRouter()
+	s := r.Host("{subdomain}.domain.com").Subrouter()
+	s.Path("/articles/{category}/{id:[0-9]+}").
+	  HandlerFunc(ArticleHandler).
+	  Name("article")
+
+	// "http://news.domain.com/articles/technology/42"
+	url, err := r.Get("article").URL("subdomain", "news",
+	                                 "category", "technology",
+	                                 "id", "42")
+
+Mux supports the addition of middlewares to a Router, which are executed in the order they are added if a match is found, including its subrouters. Middlewares are (typically) small pieces of code which take one request, do something with it, and pass it down to another middleware or the final handler. Some common use cases for middleware are request logging, header manipulation, or ResponseWriter hijacking.
+
+	type MiddlewareFunc func(http.Handler) http.Handler
+
+Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed to it, and then calls the handler passed as parameter to the MiddlewareFunc (closures can access variables from the context where they are created).
+
+A very basic middleware which logs the URI of the request being handled could be written as:
+
+	func simpleMw(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			// Do stuff here
+			log.Println(r.RequestURI)
+			// Call the next handler, which can be another middleware in the chain, or the final handler.
+			next.ServeHTTP(w, r)
+		})
+	}
+
+Middlewares can be added to a router using `Router.Use()`:
+
+	r := mux.NewRouter()
+	r.HandleFunc("/", handler)
+	r.Use(simpleMw)
+
+A more complex authentication middleware, which maps session token to users, could be written as:
+
+	// Define our struct
+	type authenticationMiddleware struct {
+		tokenUsers map[string]string
+	}
+
+	// Initialize it somewhere
+	func (amw *authenticationMiddleware) Populate() {
+		amw.tokenUsers["00000000"] = "user0"
+		amw.tokenUsers["aaaaaaaa"] = "userA"
+		amw.tokenUsers["05f717e5"] = "randomUser"
+		amw.tokenUsers["deadbeef"] = "user0"
+	}
+
+	// Middleware function, which will be called for each request
+	func (amw *authenticationMiddleware) Middleware(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			token := r.Header.Get("X-Session-Token")
+
+			if user, found := amw.tokenUsers[token]; found {
+				// We found the token in our map
+				log.Printf("Authenticated user %s\n", user)
+				next.ServeHTTP(w, r)
+			} else {
+				http.Error(w, "Forbidden", http.StatusForbidden)
+			}
+		})
+	}
+
+	r := mux.NewRouter()
+	r.HandleFunc("/", handler)
+
+	amw := authenticationMiddleware{tokenUsers: make(map[string]string)}
+	amw.Populate()
+
+	r.Use(amw.Middleware)
+
+Note: The handler chain will be stopped if your middleware doesn't call `next.ServeHTTP()` with the corresponding parameters. This can be used to abort a request if the middleware writer wants to.
+
+*/
+package mux
@@ -0,0 +1,3 @@
+module github.com/gorilla/mux
+
+go 1.12
@@ -0,0 +1,74 @@
+package mux
+
+import (
+	"net/http"
+	"strings"
+)
+
+// MiddlewareFunc is a function which receives an http.Handler and returns another http.Handler.
+// Typically, the returned handler is a closure which does something with the http.ResponseWriter and http.Request passed
+// to it, and then calls the handler passed as parameter to the MiddlewareFunc.
+type MiddlewareFunc func(http.Handler) http.Handler
+
+// middleware interface is anything which implements a MiddlewareFunc named Middleware.
+type middleware interface {
+	Middleware(handler http.Handler) http.Handler
+}
+
+// Middleware allows MiddlewareFunc to implement the middleware interface.
+func (mw MiddlewareFunc) Middleware(handler http.Handler) http.Handler {
+	return mw(handler)
+}
+
+// Use appends a MiddlewareFunc to the chain. Middleware can be used to intercept or otherwise modify requests and/or responses, and are executed in the order that they are applied to the Router.
+func (r *Router) Use(mwf ...MiddlewareFunc) {
+	for _, fn := range mwf {
+		r.middlewares = append(r.middlewares, fn)
+	}
+}
+
+// useInterface appends a middleware to the chain. Middleware can be used to intercept or otherwise modify requests and/or responses, and are executed in the order that they are applied to the Router.
+func (r *Router) useInterface(mw middleware) {
+	r.middlewares = append(r.middlewares, mw)
+}
+
+// CORSMethodMiddleware automatically sets the Access-Control-Allow-Methods response header
+// on requests for routes that have an OPTIONS method matcher to all the method matchers on
+// the route. Routes that do not explicitly handle OPTIONS requests will not be processed
+// by the middleware. See examples for usage.
+func CORSMethodMiddleware(r *Router) MiddlewareFunc {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+			allMethods, err := getAllMethodsForRoute(r, req)
+			if err == nil {
+				for _, v := range allMethods {
+					if v == http.MethodOptions {
+						w.Header().Set("Access-Control-Allow-Methods", strings.Join(allMethods, ","))
+					}
+				}
+			}
+
+			next.ServeHTTP(w, req)
+		})
+	}
+}
+
+// getAllMethodsForRoute returns all the methods from method matchers matching a given
+// request.
+func getAllMethodsForRoute(r *Router, req *http.Request) ([]string, error) {
+	var allMethods []string
+
+	for _, route := range r.routes {
+		var match RouteMatch
+		if route.Match(req, &match) || match.MatchErr == ErrMethodMismatch {
+			methods, err := route.GetMethods()
+			if err != nil {
+				return nil, err
+			}
+
+			allMethods = append(allMethods, methods...)
+		}
+	}
+
+	return allMethods, nil
+}
@@ -0,0 +1,607 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mux
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"path"
+	"regexp"
+)
+
+var (
+	// ErrMethodMismatch is returned when the method in the request does not match
+	// the method defined against the route.
+	ErrMethodMismatch = errors.New("method is not allowed")
+	// ErrNotFound is returned when no route match is found.
+	ErrNotFound = errors.New("no matching route was found")
+)
+
+// NewRouter returns a new router instance.
+func NewRouter() *Router {
+	return &Router{namedRoutes: make(map[string]*Route)}
+}
+
+// Router registers routes to be matched and dispatches a handler.
+//
+// It implements the http.Handler interface, so it can be registered to serve
+// requests:
+//
+//     var router = mux.NewRouter()
+//
+//     func main() {
+//         http.Handle("/", router)
+//     }
+//
+// Or, for Google App Engine, register it in a init() function:
+//
+//     func init() {
+//         http.Handle("/", router)
+//     }
+//
+// This will send all incoming requests to the router.
+type Router struct {
+	// Configurable Handler to be used when no route matches.
+	NotFoundHandler http.Handler
+
+	// Configurable Handler to be used when the request method does not match the route.
+	MethodNotAllowedHandler http.Handler
+
+	// Routes to be matched, in order.
+	routes []*Route
+
+	// Routes by name for URL building.
+	namedRoutes map[string]*Route
+
+	// If true, do not clear the request context after handling the request.
+	//
+	// Deprecated: No effect, since the context is stored on the request itself.
+	KeepContext bool
+
+	// Slice of middlewares to be called after a match is found
+	middlewares []middleware
+
+	// configuration shared with `Route`
+	routeConf
+}
+
+// common route configuration shared between `Router` and `Route`
+type routeConf struct {
+	// If true, "/path/foo%2Fbar/to" will match the path "/path/{var}/to"
+	useEncodedPath bool
+
+	// If true, when the path pattern is "/path/", accessing "/path" will
+	// redirect to the former and vice versa.
+	strictSlash bool
+
+	// If true, when the path pattern is "/path//to", accessing "/path//to"
+	// will not redirect
+	skipClean bool
+
+	// Manager for the variables from host and path.
+	regexp routeRegexpGroup
+
+	// List of matchers.
+	matchers []matcher
+
+	// The scheme used when building URLs.
+	buildScheme string
+
+	buildVarsFunc BuildVarsFunc
+}
+
+// returns an effective deep copy of `routeConf`
+func copyRouteConf(r routeConf) routeConf {
+	c := r
+
+	if r.regexp.path != nil {
+		c.regexp.path = copyRouteRegexp(r.regexp.path)
+	}
+
+	if r.regexp.host != nil {
+		c.regexp.host = copyRouteRegexp(r.regexp.host)
+	}
+
+	c.regexp.queries = make([]*routeRegexp, 0, len(r.regexp.queries))
+	for _, q := range r.regexp.queries {
+		c.regexp.queries = append(c.regexp.queries, copyRouteRegexp(q))
+	}
+
+	c.matchers = make([]matcher, len(r.matchers))
+	copy(c.matchers, r.matchers)
+
+	return c
+}
+
+func copyRouteRegexp(r *routeRegexp) *routeRegexp {
+	c := *r
+	return &c
+}
+
+// Match attempts to match the given request against the router's registered routes.
+//
+// If the request matches a route of this router or one of its subrouters the Route,
+// Handler, and Vars fields of the the match argument are filled and this function
+// returns true.
+//
+// If the request does not match any of this router's or its subrouters' routes
+// then this function returns false. If available, a reason for the match failure
+// will be filled in the match argument's MatchErr field. If the match failure type
+// (eg: not found) has a registered handler, the handler is assigned to the Handler
+// field of the match argument.
+func (r *Router) Match(req *http.Request, match *RouteMatch) bool {
+	for _, route := range r.routes {
+		if route.Match(req, match) {
+			// Build middleware chain if no error was found
+			if match.MatchErr == nil {
+				for i := len(r.middlewares) - 1; i >= 0; i-- {
+					match.Handler = r.middlewares[i].Middleware(match.Handler)
+				}
+			}
+			return true
+		}
+	}
+
+	if match.MatchErr == ErrMethodMismatch {
+		if r.MethodNotAllowedHandler != nil {
+			match.Handler = r.MethodNotAllowedHandler
+			return true
+		}
+
+		return false
+	}
+
+	// Closest match for a router (includes sub-routers)
+	if r.NotFoundHandler != nil {
+		match.Handler = r.NotFoundHandler
+		match.MatchErr = ErrNotFound
+		return true
+	}
+
+	match.MatchErr = ErrNotFound
+	return false
+}
+
+// ServeHTTP dispatches the handler registered in the matched route.
+//
+// When there is a match, the route variables can be retrieved calling
+// mux.Vars(request).
+func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	if !r.skipClean {
+		path := req.URL.Path
+		if r.useEncodedPath {
+			path = req.URL.EscapedPath()
+		}
+		// Clean path to canonical form and redirect.
+		if p := cleanPath(path); p != path {
+
+			// Added 3 lines (Philip Schlump) - It was dropping the query string and #whatever from query.
+			// This matches with fix in go 1.2 r.c. 4 for same problem.  Go Issue:
+			// http://code.google.com/p/go/issues/detail?id=5252
+			url := *req.URL
+			url.Path = p
+			p = url.String()
+
+			w.Header().Set("Location", p)
+			w.WriteHeader(http.StatusMovedPermanently)
+			return
+		}
+	}
+	var match RouteMatch
+	var handler http.Handler
+	if r.Match(req, &match) {
+		handler = match.Handler
+		req = requestWithVars(req, match.Vars)
+		req = requestWithRoute(req, match.Route)
+	}
+
+	if handler == nil && match.MatchErr == ErrMethodMismatch {
+		handler = methodNotAllowedHandler()
+	}
+
+	if handler == nil {
+		handler = http.NotFoundHandler()
+	}
+
+	handler.ServeHTTP(w, req)
+}
+
+// Get returns a route registered with the given name.
+func (r *Router) Get(name string) *Route {
+	return r.namedRoutes[name]
+}
+
+// GetRoute returns a route registered with the given name. This method
+// was renamed to Get() and remains here for backwards compatibility.
+func (r *Router) GetRoute(name string) *Route {
+	return r.namedRoutes[name]
+}
+
+// StrictSlash defines the trailing slash behavior for new routes. The initial
+// value is false.
+//
+// When true, if the route path is "/path/", accessing "/path" will perform a redirect
+// to the former and vice versa. In other words, your application will always
+// see the path as specified in the route.
+//
+// When false, if the route path is "/path", accessing "/path/" will not match
+// this route and vice versa.
+//
+// The re-direct is a HTTP 301 (Moved Permanently). Note that when this is set for
+// routes with a non-idempotent method (e.g. POST, PUT), the subsequent re-directed
+// request will be made as a GET by most clients. Use middleware or client settings
+// to modify this behaviour as needed.
+//
+// Special case: when a route sets a path prefix using the PathPrefix() method,
+// strict slash is ignored for that route because the redirect behavior can't
+// be determined from a prefix alone. However, any subrouters created from that
+// route inherit the original StrictSlash setting.
+func (r *Router) StrictSlash(value bool) *Router {
+	r.strictSlash = value
+	return r
+}
+
+// SkipClean defines the path cleaning behaviour for new routes. The initial
+// value is false. Users should be careful about which routes are not cleaned
+//
+// When true, if the route path is "/path//to", it will remain with the double
+// slash. This is helpful if you have a route like: /fetch/http://xkcd.com/534/
+//
+// When false, the path will be cleaned, so /fetch/http://xkcd.com/534/ will
+// become /fetch/http/xkcd.com/534
+func (r *Router) SkipClean(value bool) *Router {
+	r.skipClean = value
+	return r
+}
+
+// UseEncodedPath tells the router to match the encoded original path
+// to the routes.
+// For eg. "/path/foo%2Fbar/to" will match the path "/path/{var}/to".
+//
+// If not called, the router will match the unencoded path to the routes.
+// For eg. "/path/foo%2Fbar/to" will match the path "/path/foo/bar/to"
+func (r *Router) UseEncodedPath() *Router {
+	r.useEncodedPath = true
+	return r
+}
+
+// ----------------------------------------------------------------------------
+// Route factories
+// ----------------------------------------------------------------------------
+
+// NewRoute registers an empty route.
+func (r *Router) NewRoute() *Route {
+	// initialize a route with a copy of the parent router's configuration
+	route := &Route{routeConf: copyRouteConf(r.routeConf), namedRoutes: r.namedRoutes}
+	r.routes = append(r.routes, route)
+	return route
+}
+
+// Name registers a new route with a name.
+// See Route.Name().
+func (r *Router) Name(name string) *Route {
+	return r.NewRoute().Name(name)
+}
+
+// Handle registers a new route with a matcher for the URL path.
+// See Route.Path() and Route.Handler().
+func (r *Router) Handle(path string, handler http.Handler) *Route {
+	return r.NewRoute().Path(path).Handler(handler)
+}
+
+// HandleFunc registers a new route with a matcher for the URL path.
+// See Route.Path() and Route.HandlerFunc().
+func (r *Router) HandleFunc(path string, f func(http.ResponseWriter,
+	*http.Request)) *Route {
+	return r.NewRoute().Path(path).HandlerFunc(f)
+}
+
+// Headers registers a new route with a matcher for request header values.
+// See Route.Headers().
+func (r *Router) Headers(pairs ...string) *Route {
+	return r.NewRoute().Headers(pairs...)
+}
+
+// Host registers a new route with a matcher for the URL host.
+// See Route.Host().
+func (r *Router) Host(tpl string) *Route {
+	return r.NewRoute().Host(tpl)
+}
+
+// MatcherFunc registers a new route with a custom matcher function.
+// See Route.MatcherFunc().
+func (r *Router) MatcherFunc(f MatcherFunc) *Route {
+	return r.NewRoute().MatcherFunc(f)
+}
+
+// Methods registers a new route with a matcher for HTTP methods.
+// See Route.Methods().
+func (r *Router) Methods(methods ...string) *Route {
+	return r.NewRoute().Methods(methods...)
+}
+
+// Path registers a new route with a matcher for the URL path.
+// See Route.Path().
+func (r *Router) Path(tpl string) *Route {
+	return r.NewRoute().Path(tpl)
+}
+
+// PathPrefix registers a new route with a matcher for the URL path prefix.
+// See Route.PathPrefix().
+func (r *Router) PathPrefix(tpl string) *Route {
+	return r.NewRoute().PathPrefix(tpl)
+}
+
+// Queries registers a new route with a matcher for URL query values.
+// See Route.Queries().
+func (r *Router) Queries(pairs ...string) *Route {
+	return r.NewRoute().Queries(pairs...)
+}
+
+// Schemes registers a new route with a matcher for URL schemes.
+// See Route.Schemes().
+func (r *Router) Schemes(schemes ...string) *Route {
+	return r.NewRoute().Schemes(schemes...)
+}
+
+// BuildVarsFunc registers a new route with a custom function for modifying
+// route variables before building a URL.
+func (r *Router) BuildVarsFunc(f BuildVarsFunc) *Route {
+	return r.NewRoute().BuildVarsFunc(f)
+}
+
+// Walk walks the router and all its sub-routers, calling walkFn for each route
+// in the tree. The routes are walked in the order they were added. Sub-routers
+// are explored depth-first.
+func (r *Router) Walk(walkFn WalkFunc) error {
+	return r.walk(walkFn, []*Route{})
+}
+
+// SkipRouter is used as a return value from WalkFuncs to indicate that the
+// router that walk is about to descend down to should be skipped.
+var SkipRouter = errors.New("skip this router")
+
+// WalkFunc is the type of the function called for each route visited by Walk.
+// At every invocation, it is given the current route, and the current router,
+// and a list of ancestor routes that lead to the current route.
+type WalkFunc func(route *Route, router *Router, ancestors []*Route) error
+
+func (r *Router) walk(walkFn WalkFunc, ancestors []*Route) error {
+	for _, t := range r.routes {
+		err := walkFn(t, r, ancestors)
+		if err == SkipRouter {
+			continue
+		}
+		if err != nil {
+			return err
+		}
+		for _, sr := range t.matchers {
+			if h, ok := sr.(*Router); ok {
+				ancestors = append(ancestors, t)
+				err := h.walk(walkFn, ancestors)
+				if err != nil {
+					return err
+				}
+				ancestors = ancestors[:len(ancestors)-1]
+			}
+		}
+		if h, ok := t.handler.(*Router); ok {
+			ancestors = append(ancestors, t)
+			err := h.walk(walkFn, ancestors)
+			if err != nil {
+				return err
+			}
+			ancestors = ancestors[:len(ancestors)-1]
+		}
+	}
+	return nil
+}
+
+// ----------------------------------------------------------------------------
+// Context
+// ----------------------------------------------------------------------------
+
+// RouteMatch stores information about a matched route.
+type RouteMatch struct {
+	Route   *Route
+	Handler http.Handler
+	Vars    map[string]string
+
+	// MatchErr is set to appropriate matching error
+	// It is set to ErrMethodMismatch if there is a mismatch in
+	// the request method and route method
+	MatchErr error
+}
+
+type contextKey int
+
+const (
+	varsKey contextKey = iota
+	routeKey
+)
+
+// Vars returns the route variables for the current request, if any.
+func Vars(r *http.Request) map[string]string {
+	if rv := r.Context().Value(varsKey); rv != nil {
+		return rv.(map[string]string)
+	}
+	return nil
+}
+
+// CurrentRoute returns the matched route for the current request, if any.
+// This only works when called inside the handler of the matched route
+// because the matched route is stored in the request context which is cleared
+// after the handler returns, unless the KeepContext option is set on the
+// Router.
+func CurrentRoute(r *http.Request) *Route {
+	if rv := r.Context().Value(routeKey); rv != nil {
+		return rv.(*Route)
+	}
+	return nil
+}
+
+func requestWithVars(r *http.Request, vars map[string]string) *http.Request {
+	ctx := context.WithValue(r.Context(), varsKey, vars)
+	return r.WithContext(ctx)
+}
+
+func requestWithRoute(r *http.Request, route *Route) *http.Request {
+	ctx := context.WithValue(r.Context(), routeKey, route)
+	return r.WithContext(ctx)
+}
+
+// ----------------------------------------------------------------------------
+// Helpers
+// ----------------------------------------------------------------------------
+
+// cleanPath returns the canonical path for p, eliminating . and .. elements.
+// Borrowed from the net/http package.
+func cleanPath(p string) string {
+	if p == "" {
+		return "/"
+	}
+	if p[0] != '/' {
+		p = "/" + p
+	}
+	np := path.Clean(p)
+	// path.Clean removes trailing slash except for root;
+	// put the trailing slash back if necessary.
+	if p[len(p)-1] == '/' && np != "/" {
+		np += "/"
+	}
+
+	return np
+}
+
+// uniqueVars returns an error if two slices contain duplicated strings.
+func uniqueVars(s1, s2 []string) error {
+	for _, v1 := range s1 {
+		for _, v2 := range s2 {
+			if v1 == v2 {
+				return fmt.Errorf("mux: duplicated route variable %q", v2)
+			}
+		}
+	}
+	return nil
+}
+
+// checkPairs returns the count of strings passed in, and an error if
+// the count is not an even number.
+func checkPairs(pairs ...string) (int, error) {
+	length := len(pairs)
+	if length%2 != 0 {
+		return length, fmt.Errorf(
+			"mux: number of parameters must be multiple of 2, got %v", pairs)
+	}
+	return length, nil
+}
+
+// mapFromPairsToString converts variadic string parameters to a
+// string to string map.
+func mapFromPairsToString(pairs ...string) (map[string]string, error) {
+	length, err := checkPairs(pairs...)
+	if err != nil {
+		return nil, err
+	}
+	m := make(map[string]string, length/2)
+	for i := 0; i < length; i += 2 {
+		m[pairs[i]] = pairs[i+1]
+	}
+	return m, nil
+}
+
+// mapFromPairsToRegex converts variadic string parameters to a
+// string to regex map.
+func mapFromPairsToRegex(pairs ...string) (map[string]*regexp.Regexp, error) {
+	length, err := checkPairs(pairs...)
+	if err != nil {
+		return nil, err
+	}
+	m := make(map[string]*regexp.Regexp, length/2)
+	for i := 0; i < length; i += 2 {
+		regex, err := regexp.Compile(pairs[i+1])
+		if err != nil {
+			return nil, err
+		}
+		m[pairs[i]] = regex
+	}
+	return m, nil
+}
+
+// matchInArray returns true if the given string value is in the array.
+func matchInArray(arr []string, value string) bool {
+	for _, v := range arr {
+		if v == value {
+			return true
+		}
+	}
+	return false
+}
+
+// matchMapWithString returns true if the given key/value pairs exist in a given map.
+func matchMapWithString(toCheck map[string]string, toMatch map[string][]string, canonicalKey bool) bool {
+	for k, v := range toCheck {
+		// Check if key exists.
+		if canonicalKey {
+			k = http.CanonicalHeaderKey(k)
+		}
+		if values := toMatch[k]; values == nil {
+			return false
+		} else if v != "" {
+			// If value was defined as an empty string we only check that the
+			// key exists. Otherwise we also check for equality.
+			valueExists := false
+			for _, value := range values {
+				if v == value {
+					valueExists = true
+					break
+				}
+			}
+			if !valueExists {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// matchMapWithRegex returns true if the given key/value pairs exist in a given map compiled against
+// the given regex
+func matchMapWithRegex(toCheck map[string]*regexp.Regexp, toMatch map[string][]string, canonicalKey bool) bool {
+	for k, v := range toCheck {
+		// Check if key exists.
+		if canonicalKey {
+			k = http.CanonicalHeaderKey(k)
+		}
+		if values := toMatch[k]; values == nil {
+			return false
+		} else if v != nil {
+			// If value was defined as an empty string we only check that the
+			// key exists. Otherwise we also check for equality.
+			valueExists := false
+			for _, value := range values {
+				if v.MatchString(value) {
+					valueExists = true
+					break
+				}
+			}
+			if !valueExists {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// methodNotAllowed replies to the request with an HTTP status code 405.
+func methodNotAllowed(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(http.StatusMethodNotAllowed)
+}
+
+// methodNotAllowedHandler returns a simple request handler
+// that replies to each request with a status code 405.
+func methodNotAllowedHandler() http.Handler { return http.HandlerFunc(methodNotAllowed) }
@@ -0,0 +1,382 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mux
+
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type routeRegexpOptions struct {
+	strictSlash    bool
+	useEncodedPath bool
+}
+
+type regexpType int
+
+const (
+	regexpTypePath   regexpType = 0
+	regexpTypeHost   regexpType = 1
+	regexpTypePrefix regexpType = 2
+	regexpTypeQuery  regexpType = 3
+)
+
+// newRouteRegexp parses a route template and returns a routeRegexp,
+// used to match a host, a path or a query string.
+//
+// It will extract named variables, assemble a regexp to be matched, create
+// a "reverse" template to build URLs and compile regexps to validate variable
+// values used in URL building.
+//
+// Previously we accepted only Python-like identifiers for variable
+// names ([a-zA-Z_][a-zA-Z0-9_]*), but currently the only restriction is that
+// name and pattern can't be empty, and names can't contain a colon.
+func newRouteRegexp(tpl string, typ regexpType, options routeRegexpOptions) (*routeRegexp, error) {
+	// Check if it is well-formed.
+	idxs, errBraces := braceIndices(tpl)
+	if errBraces != nil {
+		return nil, errBraces
+	}
+	// Backup the original.
+	template := tpl
+	// Now let's parse it.
+	defaultPattern := "[^/]+"
+	if typ == regexpTypeQuery {
+		defaultPattern = ".*"
+	} else if typ == regexpTypeHost {
+		defaultPattern = "[^.]+"
+	}
+	// Only match strict slash if not matching
+	if typ != regexpTypePath {
+		options.strictSlash = false
+	}
+	// Set a flag for strictSlash.
+	endSlash := false
+	if options.strictSlash && strings.HasSuffix(tpl, "/") {
+		tpl = tpl[:len(tpl)-1]
+		endSlash = true
+	}
+	varsN := make([]string, len(idxs)/2)
+	varsR := make([]*regexp.Regexp, len(idxs)/2)
+	pattern := bytes.NewBufferString("")
+	pattern.WriteByte('^')
+	reverse := bytes.NewBufferString("")
+	var end int
+	var err error
+	for i := 0; i < len(idxs); i += 2 {
+		// Set all values we are interested in.
+		raw := tpl[end:idxs[i]]
+		end = idxs[i+1]
+		parts := strings.SplitN(tpl[idxs[i]+1:end-1], ":", 2)
+		name := parts[0]
+		patt := defaultPattern
+		if len(parts) == 2 {
+			patt = parts[1]
+		}
+		// Name or pattern can't be empty.
+		if name == "" || patt == "" {
+			return nil, fmt.Errorf("mux: missing name or pattern in %q",
+				tpl[idxs[i]:end])
+		}
+		// Build the regexp pattern.
+		fmt.Fprintf(pattern, "%s(?P<%s>%s)", regexp.QuoteMeta(raw), varGroupName(i/2), patt)
+
+		// Build the reverse template.
+		fmt.Fprintf(reverse, "%s%%s", raw)
+
+		// Append variable name and compiled pattern.
+		varsN[i/2] = name
+		varsR[i/2], err = regexp.Compile(fmt.Sprintf("^%s$", patt))
+		if err != nil {
+			return nil, err
+		}
+	}
+	// Add the remaining.
+	raw := tpl[end:]
+	pattern.WriteString(regexp.QuoteMeta(raw))
+	if options.strictSlash {
+		pattern.WriteString("[/]?")
+	}
+	if typ == regexpTypeQuery {
+		// Add the default pattern if the query value is empty
+		if queryVal := strings.SplitN(template, "=", 2)[1]; queryVal == "" {
+			pattern.WriteString(defaultPattern)
+		}
+	}
+	if typ != regexpTypePrefix {
+		pattern.WriteByte('$')
+	}
+
+	var wildcardHostPort bool
+	if typ == regexpTypeHost {
+		if !strings.Contains(pattern.String(), ":") {
+			wildcardHostPort = true
+		}
+	}
+	reverse.WriteString(raw)
+	if endSlash {
+		reverse.WriteByte('/')
+	}
+	// Compile full regexp.
+	reg, errCompile := regexp.Compile(pattern.String())
+	if errCompile != nil {
+		return nil, errCompile
+	}
+
+	// Check for capturing groups which used to work in older versions
+	if reg.NumSubexp() != len(idxs)/2 {
+		panic(fmt.Sprintf("route %s contains capture groups in its regexp. ", template) +
+			"Only non-capturing groups are accepted: e.g. (?:pattern) instead of (pattern)")
+	}
+
+	// Done!
+	return &routeRegexp{
+		template:         template,
+		regexpType:       typ,
+		options:          options,
+		regexp:           reg,
+		reverse:          reverse.String(),
+		varsN:            varsN,
+		varsR:            varsR,
+		wildcardHostPort: wildcardHostPort,
+	}, nil
+}
+
+// routeRegexp stores a regexp to match a host or path and information to
+// collect and validate route variables.
+type routeRegexp struct {
+	// The unmodified template.
+	template string
+	// The type of match
+	regexpType regexpType
+	// Options for matching
+	options routeRegexpOptions
+	// Expanded regexp.
+	regexp *regexp.Regexp
+	// Reverse template.
+	reverse string
+	// Variable names.
+	varsN []string
+	// Variable regexps (validators).
+	varsR []*regexp.Regexp
+	// Wildcard host-port (no strict port match in hostname)
+	wildcardHostPort bool
+}
+
+// Match matches the regexp against the URL host or path.
+func (r *routeRegexp) Match(req *http.Request, match *RouteMatch) bool {
+	if r.regexpType == regexpTypeHost {
+		host := getHost(req)
+		if r.wildcardHostPort {
+			// Don't be strict on the port match
+			if i := strings.Index(host, ":"); i != -1 {
+				host = host[:i]
+			}
+		}
+		return r.regexp.MatchString(host)
+	}
+
+	if r.regexpType == regexpTypeQuery {
+		return r.matchQueryString(req)
+	}
+	path := req.URL.Path
+	if r.options.useEncodedPath {
+		path = req.URL.EscapedPath()
+	}
+	return r.regexp.MatchString(path)
+}
+
+// url builds a URL part using the given values.
+func (r *routeRegexp) url(values map[string]string) (string, error) {
+	urlValues := make([]interface{}, len(r.varsN), len(r.varsN))
+	for k, v := range r.varsN {
+		value, ok := values[v]
+		if !ok {
+			return "", fmt.Errorf("mux: missing route variable %q", v)
+		}
+		if r.regexpType == regexpTypeQuery {
+			value = url.QueryEscape(value)
+		}
+		urlValues[k] = value
+	}
+	rv := fmt.Sprintf(r.reverse, urlValues...)
+	if !r.regexp.MatchString(rv) {
+		// The URL is checked against the full regexp, instead of checking
+		// individual variables. This is faster but to provide a good error
+		// message, we check individual regexps if the URL doesn't match.
+		for k, v := range r.varsN {
+			if !r.varsR[k].MatchString(values[v]) {
+				return "", fmt.Errorf(
+					"mux: variable %q doesn't match, expected %q", values[v],
+					r.varsR[k].String())
+			}
+		}
+	}
+	return rv, nil
+}
+
+// getURLQuery returns a single query parameter from a request URL.
+// For a URL with foo=bar&baz=ding, we return only the relevant key
+// value pair for the routeRegexp.
+func (r *routeRegexp) getURLQuery(req *http.Request) string {
+	if r.regexpType != regexpTypeQuery {
+		return ""
+	}
+	templateKey := strings.SplitN(r.template, "=", 2)[0]
+	val, ok := findFirstQueryKey(req.URL.RawQuery, templateKey)
+	if ok {
+		return templateKey + "=" + val
+	}
+	return ""
+}
+
+// findFirstQueryKey returns the same result as (*url.URL).Query()[key][0].
+// If key was not found, empty string and false is returned.
+func findFirstQueryKey(rawQuery, key string) (value string, ok bool) {
+	query := []byte(rawQuery)
+	for len(query) > 0 {
+		foundKey := query
+		if i := bytes.IndexAny(foundKey, "&;"); i >= 0 {
+			foundKey, query = foundKey[:i], foundKey[i+1:]
+		} else {
+			query = query[:0]
+		}
+		if len(foundKey) == 0 {
+			continue
+		}
+		var value []byte
+		if i := bytes.IndexByte(foundKey, '='); i >= 0 {
+			foundKey, value = foundKey[:i], foundKey[i+1:]
+		}
+		if len(foundKey) < len(key) {
+			// Cannot possibly be key.
+			continue
+		}
+		keyString, err := url.QueryUnescape(string(foundKey))
+		if err != nil {
+			continue
+		}
+		if keyString != key {
+			continue
+		}
+		valueString, err := url.QueryUnescape(string(value))
+		if err != nil {
+			continue
+		}
+		return valueString, true
+	}
+	return "", false
+}
+
+func (r *routeRegexp) matchQueryString(req *http.Request) bool {
+	return r.regexp.MatchString(r.getURLQuery(req))
+}
+
+// braceIndices returns the first level curly brace indices from a string.
+// It returns an error in case of unbalanced braces.
+func braceIndices(s string) ([]int, error) {
+	var level, idx int
+	var idxs []int
+	for i := 0; i < len(s); i++ {
+		switch s[i] {
+		case '{':
+			if level++; level == 1 {
+				idx = i
+			}
+		case '}':
+			if level--; level == 0 {
+				idxs = append(idxs, idx, i+1)
+			} else if level < 0 {
+				return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
+			}
+		}
+	}
+	if level != 0 {
+		return nil, fmt.Errorf("mux: unbalanced braces in %q", s)
+	}
+	return idxs, nil
+}
+
+// varGroupName builds a capturing group name for the indexed variable.
+func varGroupName(idx int) string {
+	return "v" + strconv.Itoa(idx)
+}
+
+// ----------------------------------------------------------------------------
+// routeRegexpGroup
+// ----------------------------------------------------------------------------
+
+// routeRegexpGroup groups the route matchers that carry variables.
+type routeRegexpGroup struct {
+	host    *routeRegexp
+	path    *routeRegexp
+	queries []*routeRegexp
+}
+
+// setMatch extracts the variables from the URL once a route matches.
+func (v routeRegexpGroup) setMatch(req *http.Request, m *RouteMatch, r *Route) {
+	// Store host variables.
+	if v.host != nil {
+		host := getHost(req)
+		matches := v.host.regexp.FindStringSubmatchIndex(host)
+		if len(matches) > 0 {
+			extractVars(host, matches, v.host.varsN, m.Vars)
+		}
+	}
+	path := req.URL.Path
+	if r.useEncodedPath {
+		path = req.URL.EscapedPath()
+	}
+	// Store path variables.
+	if v.path != nil {
+		matches := v.path.regexp.FindStringSubmatchIndex(path)
+		if len(matches) > 0 {
+			extractVars(path, matches, v.path.varsN, m.Vars)
+			// Check if we should redirect.
+			if v.path.options.strictSlash {
+				p1 := strings.HasSuffix(path, "/")
+				p2 := strings.HasSuffix(v.path.template, "/")
+				if p1 != p2 {
+					u, _ := url.Parse(req.URL.String())
+					if p1 {
+						u.Path = u.Path[:len(u.Path)-1]
+					} else {
+						u.Path += "/"
+					}
+					m.Handler = http.RedirectHandler(u.String(), http.StatusMovedPermanently)
+				}
+			}
+		}
+	}
+	// Store query string variables.
+	for _, q := range v.queries {
+		queryURL := q.getURLQuery(req)
+		matches := q.regexp.FindStringSubmatchIndex(queryURL)
+		if len(matches) > 0 {
+			extractVars(queryURL, matches, q.varsN, m.Vars)
+		}
+	}
+}
+
+// getHost tries its best to return the request host.
+// According to section 14.23 of RFC 2616 the Host header
+// can include the port number if the default value of 80 is not used.
+func getHost(r *http.Request) string {
+	if r.URL.IsAbs() {
+		return r.URL.Host
+	}
+	return r.Host
+}
+
+func extractVars(input string, matches []int, names []string, output map[string]string) {
+	for i, name := range names {
+		output[name] = input[matches[2*i+2]:matches[2*i+3]]
+	}
+}
@@ -0,0 +1,736 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mux
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strings"
+)
+
+// Route stores information to match a request and build URLs.
+type Route struct {
+	// Request handler for the route.
+	handler http.Handler
+	// If true, this route never matches: it is only used to build URLs.
+	buildOnly bool
+	// The name used to build URLs.
+	name string
+	// Error resulted from building a route.
+	err error
+
+	// "global" reference to all named routes
+	namedRoutes map[string]*Route
+
+	// config possibly passed in from `Router`
+	routeConf
+}
+
+// SkipClean reports whether path cleaning is enabled for this route via
+// Router.SkipClean.
+func (r *Route) SkipClean() bool {
+	return r.skipClean
+}
+
+// Match matches the route against the request.
+func (r *Route) Match(req *http.Request, match *RouteMatch) bool {
+	if r.buildOnly || r.err != nil {
+		return false
+	}
+
+	var matchErr error
+
+	// Match everything.
+	for _, m := range r.matchers {
+		if matched := m.Match(req, match); !matched {
+			if _, ok := m.(methodMatcher); ok {
+				matchErr = ErrMethodMismatch
+				continue
+			}
+
+			// Ignore ErrNotFound errors. These errors arise from match call
+			// to Subrouters.
+			//
+			// This prevents subsequent matching subrouters from failing to
+			// run middleware. If not ignored, the middleware would see a
+			// non-nil MatchErr and be skipped, even when there was a
+			// matching route.
+			if match.MatchErr == ErrNotFound {
+				match.MatchErr = nil
+			}
+
+			matchErr = nil
+			return false
+		}
+	}
+
+	if matchErr != nil {
+		match.MatchErr = matchErr
+		return false
+	}
+
+	if match.MatchErr == ErrMethodMismatch && r.handler != nil {
+		// We found a route which matches request method, clear MatchErr
+		match.MatchErr = nil
+		// Then override the mis-matched handler
+		match.Handler = r.handler
+	}
+
+	// Yay, we have a match. Let's collect some info about it.
+	if match.Route == nil {
+		match.Route = r
+	}
+	if match.Handler == nil {
+		match.Handler = r.handler
+	}
+	if match.Vars == nil {
+		match.Vars = make(map[string]string)
+	}
+
+	// Set variables.
+	r.regexp.setMatch(req, match, r)
+	return true
+}
+
+// ----------------------------------------------------------------------------
+// Route attributes
+// ----------------------------------------------------------------------------
+
+// GetError returns an error resulted from building the route, if any.
+func (r *Route) GetError() error {
+	return r.err
+}
+
+// BuildOnly sets the route to never match: it is only used to build URLs.
+func (r *Route) BuildOnly() *Route {
+	r.buildOnly = true
+	return r
+}
+
+// Handler --------------------------------------------------------------------
+
+// Handler sets a handler for the route.
+func (r *Route) Handler(handler http.Handler) *Route {
+	if r.err == nil {
+		r.handler = handler
+	}
+	return r
+}
+
+// HandlerFunc sets a handler function for the route.
+func (r *Route) HandlerFunc(f func(http.ResponseWriter, *http.Request)) *Route {
+	return r.Handler(http.HandlerFunc(f))
+}
+
+// GetHandler returns the handler for the route, if any.
+func (r *Route) GetHandler() http.Handler {
+	return r.handler
+}
+
+// Name -----------------------------------------------------------------------
+
+// Name sets the name for the route, used to build URLs.
+// It is an error to call Name more than once on a route.
+func (r *Route) Name(name string) *Route {
+	if r.name != "" {
+		r.err = fmt.Errorf("mux: route already has name %q, can't set %q",
+			r.name, name)
+	}
+	if r.err == nil {
+		r.name = name
+		r.namedRoutes[name] = r
+	}
+	return r
+}
+
+// GetName returns the name for the route, if any.
+func (r *Route) GetName() string {
+	return r.name
+}
+
+// ----------------------------------------------------------------------------
+// Matchers
+// ----------------------------------------------------------------------------
+
+// matcher types try to match a request.
+type matcher interface {
+	Match(*http.Request, *RouteMatch) bool
+}
+
+// addMatcher adds a matcher to the route.
+func (r *Route) addMatcher(m matcher) *Route {
+	if r.err == nil {
+		r.matchers = append(r.matchers, m)
+	}
+	return r
+}
+
+// addRegexpMatcher adds a host or path matcher and builder to a route.
+func (r *Route) addRegexpMatcher(tpl string, typ regexpType) error {
+	if r.err != nil {
+		return r.err
+	}
+	if typ == regexpTypePath || typ == regexpTypePrefix {
+		if len(tpl) > 0 && tpl[0] != '/' {
+			return fmt.Errorf("mux: path must start with a slash, got %q", tpl)
+		}
+		if r.regexp.path != nil {
+			tpl = strings.TrimRight(r.regexp.path.template, "/") + tpl
+		}
+	}
+	rr, err := newRouteRegexp(tpl, typ, routeRegexpOptions{
+		strictSlash:    r.strictSlash,
+		useEncodedPath: r.useEncodedPath,
+	})
+	if err != nil {
+		return err
+	}
+	for _, q := range r.regexp.queries {
+		if err = uniqueVars(rr.varsN, q.varsN); err != nil {
+			return err
+		}
+	}
+	if typ == regexpTypeHost {
+		if r.regexp.path != nil {
+			if err = uniqueVars(rr.varsN, r.regexp.path.varsN); err != nil {
+				return err
+			}
+		}
+		r.regexp.host = rr
+	} else {
+		if r.regexp.host != nil {
+			if err = uniqueVars(rr.varsN, r.regexp.host.varsN); err != nil {
+				return err
+			}
+		}
+		if typ == regexpTypeQuery {
+			r.regexp.queries = append(r.regexp.queries, rr)
+		} else {
+			r.regexp.path = rr
+		}
+	}
+	r.addMatcher(rr)
+	return nil
+}
+
+// Headers --------------------------------------------------------------------
+
+// headerMatcher matches the request against header values.
+type headerMatcher map[string]string
+
+func (m headerMatcher) Match(r *http.Request, match *RouteMatch) bool {
+	return matchMapWithString(m, r.Header, true)
+}
+
+// Headers adds a matcher for request header values.
+// It accepts a sequence of key/value pairs to be matched. For example:
+//
+//     r := mux.NewRouter()
+//     r.Headers("Content-Type", "application/json",
+//               "X-Requested-With", "XMLHttpRequest")
+//
+// The above route will only match if both request header values match.
+// If the value is an empty string, it will match any value if the key is set.
+func (r *Route) Headers(pairs ...string) *Route {
+	if r.err == nil {
+		var headers map[string]string
+		headers, r.err = mapFromPairsToString(pairs...)
+		return r.addMatcher(headerMatcher(headers))
+	}
+	return r
+}
+
+// headerRegexMatcher matches the request against the route given a regex for the header
+type headerRegexMatcher map[string]*regexp.Regexp
+
+func (m headerRegexMatcher) Match(r *http.Request, match *RouteMatch) bool {
+	return matchMapWithRegex(m, r.Header, true)
+}
+
+// HeadersRegexp accepts a sequence of key/value pairs, where the value has regex
+// support. For example:
+//
+//     r := mux.NewRouter()
+//     r.HeadersRegexp("Content-Type", "application/(text|json)",
+//               "X-Requested-With", "XMLHttpRequest")
+//
+// The above route will only match if both the request header matches both regular expressions.
+// If the value is an empty string, it will match any value if the key is set.
+// Use the start and end of string anchors (^ and $) to match an exact value.
+func (r *Route) HeadersRegexp(pairs ...string) *Route {
+	if r.err == nil {
+		var headers map[string]*regexp.Regexp
+		headers, r.err = mapFromPairsToRegex(pairs...)
+		return r.addMatcher(headerRegexMatcher(headers))
+	}
+	return r
+}
+
+// Host -----------------------------------------------------------------------
+
+// Host adds a matcher for the URL host.
+// It accepts a template with zero or more URL variables enclosed by {}.
+// Variables can define an optional regexp pattern to be matched:
+//
+// - {name} matches anything until the next dot.
+//
+// - {name:pattern} matches the given regexp pattern.
+//
+// For example:
+//
+//     r := mux.NewRouter()
+//     r.Host("www.example.com")
+//     r.Host("{subdomain}.domain.com")
+//     r.Host("{subdomain:[a-z]+}.domain.com")
+//
+// Variable names must be unique in a given route. They can be retrieved
+// calling mux.Vars(request).
+func (r *Route) Host(tpl string) *Route {
+	r.err = r.addRegexpMatcher(tpl, regexpTypeHost)
+	return r
+}
+
+// MatcherFunc ----------------------------------------------------------------
+
+// MatcherFunc is the function signature used by custom matchers.
+type MatcherFunc func(*http.Request, *RouteMatch) bool
+
+// Match returns the match for a given request.
+func (m MatcherFunc) Match(r *http.Request, match *RouteMatch) bool {
+	return m(r, match)
+}
+
+// MatcherFunc adds a custom function to be used as request matcher.
+func (r *Route) MatcherFunc(f MatcherFunc) *Route {
+	return r.addMatcher(f)
+}
+
+// Methods --------------------------------------------------------------------
+
+// methodMatcher matches the request against HTTP methods.
+type methodMatcher []string
+
+func (m methodMatcher) Match(r *http.Request, match *RouteMatch) bool {
+	return matchInArray(m, r.Method)
+}
+
+// Methods adds a matcher for HTTP methods.
+// It accepts a sequence of one or more methods to be matched, e.g.:
+// "GET", "POST", "PUT".
+func (r *Route) Methods(methods ...string) *Route {
+	for k, v := range methods {
+		methods[k] = strings.ToUpper(v)
+	}
+	return r.addMatcher(methodMatcher(methods))
+}
+
+// Path -----------------------------------------------------------------------
+
+// Path adds a matcher for the URL path.
+// It accepts a template with zero or more URL variables enclosed by {}. The
+// template must start with a "/".
+// Variables can define an optional regexp pattern to be matched:
+//
+// - {name} matches anything until the next slash.
+//
+// - {name:pattern} matches the given regexp pattern.
+//
+// For example:
+//
+//     r := mux.NewRouter()
+//     r.Path("/products/").Handler(ProductsHandler)
+//     r.Path("/products/{key}").Handler(ProductsHandler)
+//     r.Path("/articles/{category}/{id:[0-9]+}").
+//       Handler(ArticleHandler)
+//
+// Variable names must be unique in a given route. They can be retrieved
+// calling mux.Vars(request).
+func (r *Route) Path(tpl string) *Route {
+	r.err = r.addRegexpMatcher(tpl, regexpTypePath)
+	return r
+}
+
+// PathPrefix -----------------------------------------------------------------
+
+// PathPrefix adds a matcher for the URL path prefix. This matches if the given
+// template is a prefix of the full URL path. See Route.Path() for details on
+// the tpl argument.
+//
+// Note that it does not treat slashes specially ("/foobar/" will be matched by
+// the prefix "/foo") so you may want to use a trailing slash here.
+//
+// Also note that the setting of Router.StrictSlash() has no effect on routes
+// with a PathPrefix matcher.
+func (r *Route) PathPrefix(tpl string) *Route {
+	r.err = r.addRegexpMatcher(tpl, regexpTypePrefix)
+	return r
+}
+
+// Query ----------------------------------------------------------------------
+
+// Queries adds a matcher for URL query values.
+// It accepts a sequence of key/value pairs. Values may define variables.
+// For example:
+//
+//     r := mux.NewRouter()
+//     r.Queries("foo", "bar", "id", "{id:[0-9]+}")
+//
+// The above route will only match if the URL contains the defined queries
+// values, e.g.: ?foo=bar&id=42.
+//
+// If the value is an empty string, it will match any value if the key is set.
+//
+// Variables can define an optional regexp pattern to be matched:
+//
+// - {name} matches anything until the next slash.
+//
+// - {name:pattern} matches the given regexp pattern.
+func (r *Route) Queries(pairs ...string) *Route {
+	length := len(pairs)
+	if length%2 != 0 {
+		r.err = fmt.Errorf(
+			"mux: number of parameters must be multiple of 2, got %v", pairs)
+		return nil
+	}
+	for i := 0; i < length; i += 2 {
+		if r.err = r.addRegexpMatcher(pairs[i]+"="+pairs[i+1], regexpTypeQuery); r.err != nil {
+			return r
+		}
+	}
+
+	return r
+}
+
+// Schemes --------------------------------------------------------------------
+
+// schemeMatcher matches the request against URL schemes.
+type schemeMatcher []string
+
+func (m schemeMatcher) Match(r *http.Request, match *RouteMatch) bool {
+	scheme := r.URL.Scheme
+	// https://golang.org/pkg/net/http/#Request
+	// "For [most] server requests, fields other than Path and RawQuery will be
+	// empty."
+	// Since we're an http muxer, the scheme is either going to be http or https
+	// though, so we can just set it based on the tls termination state.
+	if scheme == "" {
+		if r.TLS == nil {
+			scheme = "http"
+		} else {
+			scheme = "https"
+		}
+	}
+	return matchInArray(m, scheme)
+}
+
+// Schemes adds a matcher for URL schemes.
+// It accepts a sequence of schemes to be matched, e.g.: "http", "https".
+// If the request's URL has a scheme set, it will be matched against.
+// Generally, the URL scheme will only be set if a previous handler set it,
+// such as the ProxyHeaders handler from gorilla/handlers.
+// If unset, the scheme will be determined based on the request's TLS
+// termination state.
+// The first argument to Schemes will be used when constructing a route URL.
+func (r *Route) Schemes(schemes ...string) *Route {
+	for k, v := range schemes {
+		schemes[k] = strings.ToLower(v)
+	}
+	if len(schemes) > 0 {
+		r.buildScheme = schemes[0]
+	}
+	return r.addMatcher(schemeMatcher(schemes))
+}
+
+// BuildVarsFunc --------------------------------------------------------------
+
+// BuildVarsFunc is the function signature used by custom build variable
+// functions (which can modify route variables before a route's URL is built).
+type BuildVarsFunc func(map[string]string) map[string]string
+
+// BuildVarsFunc adds a custom function to be used to modify build variables
+// before a route's URL is built.
+func (r *Route) BuildVarsFunc(f BuildVarsFunc) *Route {
+	if r.buildVarsFunc != nil {
+		// compose the old and new functions
+		old := r.buildVarsFunc
+		r.buildVarsFunc = func(m map[string]string) map[string]string {
+			return f(old(m))
+		}
+	} else {
+		r.buildVarsFunc = f
+	}
+	return r
+}
+
+// Subrouter ------------------------------------------------------------------
+
+// Subrouter creates a subrouter for the route.
+//
+// It will test the inner routes only if the parent route matched. For example:
+//
+//     r := mux.NewRouter()
+//     s := r.Host("www.example.com").Subrouter()
+//     s.HandleFunc("/products/", ProductsHandler)
+//     s.HandleFunc("/products/{key}", ProductHandler)
+//     s.HandleFunc("/articles/{category}/{id:[0-9]+}"), ArticleHandler)
+//
+// Here, the routes registered in the subrouter won't be tested if the host
+// doesn't match.
+func (r *Route) Subrouter() *Router {
+	// initialize a subrouter with a copy of the parent route's configuration
+	router := &Router{routeConf: copyRouteConf(r.routeConf), namedRoutes: r.namedRoutes}
+	r.addMatcher(router)
+	return router
+}
+
+// ----------------------------------------------------------------------------
+// URL building
+// ----------------------------------------------------------------------------
+
+// URL builds a URL for the route.
+//
+// It accepts a sequence of key/value pairs for the route variables. For
+// example, given this route:
+//
+//     r := mux.NewRouter()
+//     r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler).
+//       Name("article")
+//
+// ...a URL for it can be built using:
+//
+//     url, err := r.Get("article").URL("category", "technology", "id", "42")
+//
+// ...which will return an url.URL with the following path:
+//
+//     "/articles/technology/42"
+//
+// This also works for host variables:
+//
+//     r := mux.NewRouter()
+//     r.HandleFunc("/articles/{category}/{id:[0-9]+}", ArticleHandler).
+//       Host("{subdomain}.domain.com").
+//       Name("article")
+//
+//     // url.String() will be "http://news.domain.com/articles/technology/42"
+//     url, err := r.Get("article").URL("subdomain", "news",
+//                                      "category", "technology",
+//                                      "id", "42")
+//
+// The scheme of the resulting url will be the first argument that was passed to Schemes:
+//
+//     // url.String() will be "https://example.com"
+//     r := mux.NewRouter()
+//     url, err := r.Host("example.com")
+//                  .Schemes("https", "http").URL()
+//
+// All variables defined in the route are required, and their values must
+// conform to the corresponding patterns.
+func (r *Route) URL(pairs ...string) (*url.URL, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	values, err := r.prepareVars(pairs...)
+	if err != nil {
+		return nil, err
+	}
+	var scheme, host, path string
+	queries := make([]string, 0, len(r.regexp.queries))
+	if r.regexp.host != nil {
+		if host, err = r.regexp.host.url(values); err != nil {
+			return nil, err
+		}
+		scheme = "http"
+		if r.buildScheme != "" {
+			scheme = r.buildScheme
+		}
+	}
+	if r.regexp.path != nil {
+		if path, err = r.regexp.path.url(values); err != nil {
+			return nil, err
+		}
+	}
+	for _, q := range r.regexp.queries {
+		var query string
+		if query, err = q.url(values); err != nil {
+			return nil, err
+		}
+		queries = append(queries, query)
+	}
+	return &url.URL{
+		Scheme:   scheme,
+		Host:     host,
+		Path:     path,
+		RawQuery: strings.Join(queries, "&"),
+	}, nil
+}
+
+// URLHost builds the host part of the URL for a route. See Route.URL().
+//
+// The route must have a host defined.
+func (r *Route) URLHost(pairs ...string) (*url.URL, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	if r.regexp.host == nil {
+		return nil, errors.New("mux: route doesn't have a host")
+	}
+	values, err := r.prepareVars(pairs...)
+	if err != nil {
+		return nil, err
+	}
+	host, err := r.regexp.host.url(values)
+	if err != nil {
+		return nil, err
+	}
+	u := &url.URL{
+		Scheme: "http",
+		Host:   host,
+	}
+	if r.buildScheme != "" {
+		u.Scheme = r.buildScheme
+	}
+	return u, nil
+}
+
+// URLPath builds the path part of the URL for a route. See Route.URL().
+//
+// The route must have a path defined.
+func (r *Route) URLPath(pairs ...string) (*url.URL, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	if r.regexp.path == nil {
+		return nil, errors.New("mux: route doesn't have a path")
+	}
+	values, err := r.prepareVars(pairs...)
+	if err != nil {
+		return nil, err
+	}
+	path, err := r.regexp.path.url(values)
+	if err != nil {
+		return nil, err
+	}
+	return &url.URL{
+		Path: path,
+	}, nil
+}
+
+// GetPathTemplate returns the template used to build the
+// route match.
+// This is useful for building simple REST API documentation and for instrumentation
+// against third-party services.
+// An error will be returned if the route does not define a path.
+func (r *Route) GetPathTemplate() (string, error) {
+	if r.err != nil {
+		return "", r.err
+	}
+	if r.regexp.path == nil {
+		return "", errors.New("mux: route doesn't have a path")
+	}
+	return r.regexp.path.template, nil
+}
+
+// GetPathRegexp returns the expanded regular expression used to match route path.
+// This is useful for building simple REST API documentation and for instrumentation
+// against third-party services.
+// An error will be returned if the route does not define a path.
+func (r *Route) GetPathRegexp() (string, error) {
+	if r.err != nil {
+		return "", r.err
+	}
+	if r.regexp.path == nil {
+		return "", errors.New("mux: route does not have a path")
+	}
+	return r.regexp.path.regexp.String(), nil
+}
+
+// GetQueriesRegexp returns the expanded regular expressions used to match the
+// route queries.
+// This is useful for building simple REST API documentation and for instrumentation
+// against third-party services.
+// An error will be returned if the route does not have queries.
+func (r *Route) GetQueriesRegexp() ([]string, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	if r.regexp.queries == nil {
+		return nil, errors.New("mux: route doesn't have queries")
+	}
+	queries := make([]string, 0, len(r.regexp.queries))
+	for _, query := range r.regexp.queries {
+		queries = append(queries, query.regexp.String())
+	}
+	return queries, nil
+}
+
+// GetQueriesTemplates returns the templates used to build the
+// query matching.
+// This is useful for building simple REST API documentation and for instrumentation
+// against third-party services.
+// An error will be returned if the route does not define queries.
+func (r *Route) GetQueriesTemplates() ([]string, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	if r.regexp.queries == nil {
+		return nil, errors.New("mux: route doesn't have queries")
+	}
+	queries := make([]string, 0, len(r.regexp.queries))
+	for _, query := range r.regexp.queries {
+		queries = append(queries, query.template)
+	}
+	return queries, nil
+}
+
+// GetMethods returns the methods the route matches against
+// This is useful for building simple REST API documentation and for instrumentation
+// against third-party services.
+// An error will be returned if route does not have methods.
+func (r *Route) GetMethods() ([]string, error) {
+	if r.err != nil {
+		return nil, r.err
+	}
+	for _, m := range r.matchers {
+		if methods, ok := m.(methodMatcher); ok {
+			return []string(methods), nil
+		}
+	}
+	return nil, errors.New("mux: route doesn't have methods")
+}
+
+// GetHostTemplate returns the template used to build the
+// route match.
+// This is useful for building simple REST API documentation and for instrumentation
+// against third-party services.
+// An error will be returned if the route does not define a host.
+func (r *Route) GetHostTemplate() (string, error) {
+	if r.err != nil {
+		return "", r.err
+	}
+	if r.regexp.host == nil {
+		return "", errors.New("mux: route doesn't have a host")
+	}
+	return r.regexp.host.template, nil
+}
+
+// prepareVars converts the route variable pairs into a map. If the route has a
+// BuildVarsFunc, it is invoked.
+func (r *Route) prepareVars(pairs ...string) (map[string]string, error) {
+	m, err := mapFromPairsToString(pairs...)
+	if err != nil {
+		return nil, err
+	}
+	return r.buildVars(m), nil
+}
+
+func (r *Route) buildVars(m map[string]string) map[string]string {
+	if r.buildVarsFunc != nil {
+		m = r.buildVarsFunc(m)
+	}
+	return m
+}
@@ -0,0 +1,19 @@
+// Copyright 2012 The Gorilla Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mux
+
+import "net/http"
+
+// SetURLVars sets the URL variables for the given request, to be accessed via
+// mux.Vars for testing route behaviour. Arguments are not modified, a shallow
+// copy is returned.
+//
+// This API should only be used for testing purposes; it provides a way to
+// inject variables into the request context. Alternatively, URL variables
+// can be set by making a route that captures the required variables,
+// starting a server and sending the request to that server.
+func SetURLVars(r *http.Request, val map[string]string) *http.Request {
+	return requestWithVars(r, val)
+}
@@ -0,0 +1,3 @@
+documents
+coverage.txt
+_book
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2013-NOW  Jinzhu <wosmvp@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
@@ -0,0 +1,41 @@
+# GORM
+
+The fantastic ORM library for Golang, aims to be developer friendly.
+
+[![go report card](https://goreportcard.com/badge/github.com/jinzhu/gorm "go report card")](https://goreportcard.com/report/github.com/jinzhu/gorm)
+[![wercker status](https://app.wercker.com/status/8596cace912c9947dd9c8542ecc8cb8b/s/master "wercker status")](https://app.wercker.com/project/byKey/8596cace912c9947dd9c8542ecc8cb8b)
+[![codecov](https://codecov.io/gh/jinzhu/gorm/branch/master/graph/badge.svg)](https://codecov.io/gh/jinzhu/gorm)
+[![Join the chat at https://gitter.im/jinzhu/gorm](https://img.shields.io/gitter/room/jinzhu/gorm.svg)](https://gitter.im/jinzhu/gorm?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Open Collective Backer](https://opencollective.com/gorm/tiers/backer/badge.svg?label=backer&color=brightgreen "Open Collective Backer")](https://opencollective.com/gorm)
+[![Open Collective Sponsor](https://opencollective.com/gorm/tiers/sponsor/badge.svg?label=sponsor&color=brightgreen "Open Collective Sponsor")](https://opencollective.com/gorm)
+[![MIT license](https://img.shields.io/badge/license-MIT-brightgreen.svg)](https://opensource.org/licenses/MIT)
+[![GoDoc](https://godoc.org/github.com/jinzhu/gorm?status.svg)](https://godoc.org/github.com/jinzhu/gorm)
+
+## Overview
+
+* Full-Featured ORM (almost)
+* Associations (Has One, Has Many, Belongs To, Many To Many, Polymorphism)
+* Hooks (Before/After Create/Save/Update/Delete/Find)
+* Preloading (eager loading)
+* Transactions
+* Composite Primary Key
+* SQL Builder
+* Auto Migrations
+* Logger
+* Extendable, write Plugins based on GORM callbacks
+* Every feature comes with tests
+* Developer Friendly
+
+## Getting Started
+
+* GORM Guides [https://gorm.io](https://gorm.io)
+
+## Contributing
+
+[You can help to deliver a better GORM, check out things you can do](https://gorm.io/contribute.html)
+
+## License
+
+© Jinzhu, 2013~time.Now
+
+Released under the [MIT License](https://github.com/jinzhu/gorm/blob/master/License)
@@ -0,0 +1,377 @@
+package gorm
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+// Association Mode contains some helper methods to handle relationship things easily.
+type Association struct {
+	Error  error
+	scope  *Scope
+	column string
+	field  *Field
+}
+
+// Find find out all related associations
+func (association *Association) Find(value interface{}) *Association {
+	association.scope.related(value, association.column)
+	return association.setErr(association.scope.db.Error)
+}
+
+// Append append new associations for many2many, has_many, replace current association for has_one, belongs_to
+func (association *Association) Append(values ...interface{}) *Association {
+	if association.Error != nil {
+		return association
+	}
+
+	if relationship := association.field.Relationship; relationship.Kind == "has_one" {
+		return association.Replace(values...)
+	}
+	return association.saveAssociations(values...)
+}
+
+// Replace replace current associations with new one
+func (association *Association) Replace(values ...interface{}) *Association {
+	if association.Error != nil {
+		return association
+	}
+
+	var (
+		relationship = association.field.Relationship
+		scope        = association.scope
+		field        = association.field.Field
+		newDB        = scope.NewDB()
+	)
+
+	// Append new values
+	association.field.Set(reflect.Zero(association.field.Field.Type()))
+	association.saveAssociations(values...)
+
+	// Belongs To
+	if relationship.Kind == "belongs_to" {
+		// Set foreign key to be null when clearing value (length equals 0)
+		if len(values) == 0 {
+			// Set foreign key to be nil
+			var foreignKeyMap = map[string]interface{}{}
+			for _, foreignKey := range relationship.ForeignDBNames {
+				foreignKeyMap[foreignKey] = nil
+			}
+			association.setErr(newDB.Model(scope.Value).UpdateColumn(foreignKeyMap).Error)
+		}
+	} else {
+		// Polymorphic Relations
+		if relationship.PolymorphicDBName != "" {
+			newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(relationship.PolymorphicDBName)), relationship.PolymorphicValue)
+		}
+
+		// Delete Relations except new created
+		if len(values) > 0 {
+			var associationForeignFieldNames, associationForeignDBNames []string
+			if relationship.Kind == "many_to_many" {
+				// if many to many relations, get association fields name from association foreign keys
+				associationScope := scope.New(reflect.New(field.Type()).Interface())
+				for idx, dbName := range relationship.AssociationForeignFieldNames {
+					if field, ok := associationScope.FieldByName(dbName); ok {
+						associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
+						associationForeignDBNames = append(associationForeignDBNames, relationship.AssociationForeignDBNames[idx])
+					}
+				}
+			} else {
+				// If has one/many relations, use primary keys
+				for _, field := range scope.New(reflect.New(field.Type()).Interface()).PrimaryFields() {
+					associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
+					associationForeignDBNames = append(associationForeignDBNames, field.DBName)
+				}
+			}
+
+			newPrimaryKeys := scope.getColumnAsArray(associationForeignFieldNames, field.Interface())
+
+			if len(newPrimaryKeys) > 0 {
+				sql := fmt.Sprintf("%v NOT IN (%v)", toQueryCondition(scope, associationForeignDBNames), toQueryMarks(newPrimaryKeys))
+				newDB = newDB.Where(sql, toQueryValues(newPrimaryKeys)...)
+			}
+		}
+
+		if relationship.Kind == "many_to_many" {
+			// if many to many relations, delete related relations from join table
+			var sourceForeignFieldNames []string
+
+			for _, dbName := range relationship.ForeignFieldNames {
+				if field, ok := scope.FieldByName(dbName); ok {
+					sourceForeignFieldNames = append(sourceForeignFieldNames, field.Name)
+				}
+			}
+
+			if sourcePrimaryKeys := scope.getColumnAsArray(sourceForeignFieldNames, scope.Value); len(sourcePrimaryKeys) > 0 {
+				newDB = newDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(sourcePrimaryKeys)), toQueryValues(sourcePrimaryKeys)...)
+
+				association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB))
+			}
+		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
+			// has_one or has_many relations, set foreign key to be nil (TODO or delete them?)
+			var foreignKeyMap = map[string]interface{}{}
+			for idx, foreignKey := range relationship.ForeignDBNames {
+				foreignKeyMap[foreignKey] = nil
+				if field, ok := scope.FieldByName(relationship.AssociationForeignFieldNames[idx]); ok {
+					newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
+				}
+			}
+
+			fieldValue := reflect.New(association.field.Field.Type()).Interface()
+			association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
+		}
+	}
+	return association
+}
+
+// Delete remove relationship between source & passed arguments, but won't delete those arguments
+func (association *Association) Delete(values ...interface{}) *Association {
+	if association.Error != nil {
+		return association
+	}
+
+	var (
+		relationship = association.field.Relationship
+		scope        = association.scope
+		field        = association.field.Field
+		newDB        = scope.NewDB()
+	)
+
+	if len(values) == 0 {
+		return association
+	}
+
+	var deletingResourcePrimaryFieldNames, deletingResourcePrimaryDBNames []string
+	for _, field := range scope.New(reflect.New(field.Type()).Interface()).PrimaryFields() {
+		deletingResourcePrimaryFieldNames = append(deletingResourcePrimaryFieldNames, field.Name)
+		deletingResourcePrimaryDBNames = append(deletingResourcePrimaryDBNames, field.DBName)
+	}
+
+	deletingPrimaryKeys := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, values...)
+
+	if relationship.Kind == "many_to_many" {
+		// source value's foreign keys
+		for idx, foreignKey := range relationship.ForeignDBNames {
+			if field, ok := scope.FieldByName(relationship.ForeignFieldNames[idx]); ok {
+				newDB = newDB.Where(fmt.Sprintf("%v = ?", scope.Quote(foreignKey)), field.Field.Interface())
+			}
+		}
+
+		// get association's foreign fields name
+		var associationScope = scope.New(reflect.New(field.Type()).Interface())
+		var associationForeignFieldNames []string
+		for _, associationDBName := range relationship.AssociationForeignFieldNames {
+			if field, ok := associationScope.FieldByName(associationDBName); ok {
+				associationForeignFieldNames = append(associationForeignFieldNames, field.Name)
+			}
+		}
+
+		// association value's foreign keys
+		deletingPrimaryKeys := scope.getColumnAsArray(associationForeignFieldNames, values...)
+		sql := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(deletingPrimaryKeys))
+		newDB = newDB.Where(sql, toQueryValues(deletingPrimaryKeys)...)
+
+		association.setErr(relationship.JoinTableHandler.Delete(relationship.JoinTableHandler, newDB))
+	} else {
+		var foreignKeyMap = map[string]interface{}{}
+		for _, foreignKey := range relationship.ForeignDBNames {
+			foreignKeyMap[foreignKey] = nil
+		}
+
+		if relationship.Kind == "belongs_to" {
+			// find with deleting relation's foreign keys
+			primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, values...)
+			newDB = newDB.Where(
+				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
+				toQueryValues(primaryKeys)...,
+			)
+
+			// set foreign key to be null if there are some records affected
+			modelValue := reflect.New(scope.GetModelStruct().ModelType).Interface()
+			if results := newDB.Model(modelValue).UpdateColumn(foreignKeyMap); results.Error == nil {
+				if results.RowsAffected > 0 {
+					scope.updatedAttrsWithValues(foreignKeyMap)
+				}
+			} else {
+				association.setErr(results.Error)
+			}
+		} else if relationship.Kind == "has_one" || relationship.Kind == "has_many" {
+			// find all relations
+			primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, scope.Value)
+			newDB = newDB.Where(
+				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
+				toQueryValues(primaryKeys)...,
+			)
+
+			// only include those deleting relations
+			newDB = newDB.Where(
+				fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, deletingResourcePrimaryDBNames), toQueryMarks(deletingPrimaryKeys)),
+				toQueryValues(deletingPrimaryKeys)...,
+			)
+
+			// set matched relation's foreign key to be null
+			fieldValue := reflect.New(association.field.Field.Type()).Interface()
+			association.setErr(newDB.Model(fieldValue).UpdateColumn(foreignKeyMap).Error)
+		}
+	}
+
+	// Remove deleted records from source's field
+	if association.Error == nil {
+		if field.Kind() == reflect.Slice {
+			leftValues := reflect.Zero(field.Type())
+
+			for i := 0; i < field.Len(); i++ {
+				reflectValue := field.Index(i)
+				primaryKey := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, reflectValue.Interface())[0]
+				var isDeleted = false
+				for _, pk := range deletingPrimaryKeys {
+					if equalAsString(primaryKey, pk) {
+						isDeleted = true
+						break
+					}
+				}
+				if !isDeleted {
+					leftValues = reflect.Append(leftValues, reflectValue)
+				}
+			}
+
+			association.field.Set(leftValues)
+		} else if field.Kind() == reflect.Struct {
+			primaryKey := scope.getColumnAsArray(deletingResourcePrimaryFieldNames, field.Interface())[0]
+			for _, pk := range deletingPrimaryKeys {
+				if equalAsString(primaryKey, pk) {
+					association.field.Set(reflect.Zero(field.Type()))
+					break
+				}
+			}
+		}
+	}
+
+	return association
+}
+
+// Clear remove relationship between source & current associations, won't delete those associations
+func (association *Association) Clear() *Association {
+	return association.Replace()
+}
+
+// Count return the count of current associations
+func (association *Association) Count() int {
+	var (
+		count        = 0
+		relationship = association.field.Relationship
+		scope        = association.scope
+		fieldValue   = association.field.Field.Interface()
+		query        = scope.DB()
+	)
+
+	switch relationship.Kind {
+	case "many_to_many":
+		query = relationship.JoinTableHandler.JoinWith(relationship.JoinTableHandler, query, scope.Value)
+	case "has_many", "has_one":
+		primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, scope.Value)
+		query = query.Where(
+			fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
+			toQueryValues(primaryKeys)...,
+		)
+	case "belongs_to":
+		primaryKeys := scope.getColumnAsArray(relationship.ForeignFieldNames, scope.Value)
+		query = query.Where(
+			fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(primaryKeys)),
+			toQueryValues(primaryKeys)...,
+		)
+	}
+
+	if relationship.PolymorphicType != "" {
+		query = query.Where(
+			fmt.Sprintf("%v.%v = ?", scope.New(fieldValue).QuotedTableName(), scope.Quote(relationship.PolymorphicDBName)),
+			relationship.PolymorphicValue,
+		)
+	}
+
+	if err := query.Model(fieldValue).Count(&count).Error; err != nil {
+		association.Error = err
+	}
+	return count
+}
+
+// saveAssociations save passed values as associations
+func (association *Association) saveAssociations(values ...interface{}) *Association {
+	var (
+		scope        = association.scope
+		field        = association.field
+		relationship = field.Relationship
+	)
+
+	saveAssociation := func(reflectValue reflect.Value) {
+		// value has to been pointer
+		if reflectValue.Kind() != reflect.Ptr {
+			reflectPtr := reflect.New(reflectValue.Type())
+			reflectPtr.Elem().Set(reflectValue)
+			reflectValue = reflectPtr
+		}
+
+		// value has to been saved for many2many
+		if relationship.Kind == "many_to_many" {
+			if scope.New(reflectValue.Interface()).PrimaryKeyZero() {
+				association.setErr(scope.NewDB().Save(reflectValue.Interface()).Error)
+			}
+		}
+
+		// Assign Fields
+		var fieldType = field.Field.Type()
+		var setFieldBackToValue, setSliceFieldBackToValue bool
+		if reflectValue.Type().AssignableTo(fieldType) {
+			field.Set(reflectValue)
+		} else if reflectValue.Type().Elem().AssignableTo(fieldType) {
+			// if field's type is struct, then need to set value back to argument after save
+			setFieldBackToValue = true
+			field.Set(reflectValue.Elem())
+		} else if fieldType.Kind() == reflect.Slice {
+			if reflectValue.Type().AssignableTo(fieldType.Elem()) {
+				field.Set(reflect.Append(field.Field, reflectValue))
+			} else if reflectValue.Type().Elem().AssignableTo(fieldType.Elem()) {
+				// if field's type is slice of struct, then need to set value back to argument after save
+				setSliceFieldBackToValue = true
+				field.Set(reflect.Append(field.Field, reflectValue.Elem()))
+			}
+		}
+
+		if relationship.Kind == "many_to_many" {
+			association.setErr(relationship.JoinTableHandler.Add(relationship.JoinTableHandler, scope.NewDB(), scope.Value, reflectValue.Interface()))
+		} else {
+			association.setErr(scope.NewDB().Select(field.Name).Save(scope.Value).Error)
+
+			if setFieldBackToValue {
+				reflectValue.Elem().Set(field.Field)
+			} else if setSliceFieldBackToValue {
+				reflectValue.Elem().Set(field.Field.Index(field.Field.Len() - 1))
+			}
+		}
+	}
+
+	for _, value := range values {
+		reflectValue := reflect.ValueOf(value)
+		indirectReflectValue := reflect.Indirect(reflectValue)
+		if indirectReflectValue.Kind() == reflect.Struct {
+			saveAssociation(reflectValue)
+		} else if indirectReflectValue.Kind() == reflect.Slice {
+			for i := 0; i < indirectReflectValue.Len(); i++ {
+				saveAssociation(indirectReflectValue.Index(i))
+			}
+		} else {
+			association.setErr(errors.New("invalid value type"))
+		}
+	}
+	return association
+}
+
+// setErr set error when the error is not nil. And return Association.
+func (association *Association) setErr(err error) *Association {
+	if err != nil {
+		association.Error = err
+	}
+	return association
+}
@@ -0,0 +1,250 @@
+package gorm
+
+import "fmt"
+
+// DefaultCallback default callbacks defined by gorm
+var DefaultCallback = &Callback{logger: nopLogger{}}
+
+// Callback is a struct that contains all CRUD callbacks
+//   Field `creates` contains callbacks will be call when creating object
+//   Field `updates` contains callbacks will be call when updating object
+//   Field `deletes` contains callbacks will be call when deleting object
+//   Field `queries` contains callbacks will be call when querying object with query methods like Find, First, Related, Association...
+//   Field `rowQueries` contains callbacks will be call when querying object with Row, Rows...
+//   Field `processors` contains all callback processors, will be used to generate above callbacks in order
+type Callback struct {
+	logger     logger
+	creates    []*func(scope *Scope)
+	updates    []*func(scope *Scope)
+	deletes    []*func(scope *Scope)
+	queries    []*func(scope *Scope)
+	rowQueries []*func(scope *Scope)
+	processors []*CallbackProcessor
+}
+
+// CallbackProcessor contains callback informations
+type CallbackProcessor struct {
+	logger    logger
+	name      string              // current callback's name
+	before    string              // register current callback before a callback
+	after     string              // register current callback after a callback
+	replace   bool                // replace callbacks with same name
+	remove    bool                // delete callbacks with same name
+	kind      string              // callback type: create, update, delete, query, row_query
+	processor *func(scope *Scope) // callback handler
+	parent    *Callback
+}
+
+func (c *Callback) clone(logger logger) *Callback {
+	return &Callback{
+		logger:     logger,
+		creates:    c.creates,
+		updates:    c.updates,
+		deletes:    c.deletes,
+		queries:    c.queries,
+		rowQueries: c.rowQueries,
+		processors: c.processors,
+	}
+}
+
+// Create could be used to register callbacks for creating object
+//     db.Callback().Create().After("gorm:create").Register("plugin:run_after_create", func(*Scope) {
+//       // business logic
+//       ...
+//
+//       // set error if some thing wrong happened, will rollback the creating
+//       scope.Err(errors.New("error"))
+//     })
+func (c *Callback) Create() *CallbackProcessor {
+	return &CallbackProcessor{logger: c.logger, kind: "create", parent: c}
+}
+
+// Update could be used to register callbacks for updating object, refer `Create` for usage
+func (c *Callback) Update() *CallbackProcessor {
+	return &CallbackProcessor{logger: c.logger, kind: "update", parent: c}
+}
+
+// Delete could be used to register callbacks for deleting object, refer `Create` for usage
+func (c *Callback) Delete() *CallbackProcessor {
+	return &CallbackProcessor{logger: c.logger, kind: "delete", parent: c}
+}
+
+// Query could be used to register callbacks for querying objects with query methods like `Find`, `First`, `Related`, `Association`...
+// Refer `Create` for usage
+func (c *Callback) Query() *CallbackProcessor {
+	return &CallbackProcessor{logger: c.logger, kind: "query", parent: c}
+}
+
+// RowQuery could be used to register callbacks for querying objects with `Row`, `Rows`, refer `Create` for usage
+func (c *Callback) RowQuery() *CallbackProcessor {
+	return &CallbackProcessor{logger: c.logger, kind: "row_query", parent: c}
+}
+
+// After insert a new callback after callback `callbackName`, refer `Callbacks.Create`
+func (cp *CallbackProcessor) After(callbackName string) *CallbackProcessor {
+	cp.after = callbackName
+	return cp
+}
+
+// Before insert a new callback before callback `callbackName`, refer `Callbacks.Create`
+func (cp *CallbackProcessor) Before(callbackName string) *CallbackProcessor {
+	cp.before = callbackName
+	return cp
+}
+
+// Register a new callback, refer `Callbacks.Create`
+func (cp *CallbackProcessor) Register(callbackName string, callback func(scope *Scope)) {
+	if cp.kind == "row_query" {
+		if cp.before == "" && cp.after == "" && callbackName != "gorm:row_query" {
+			cp.logger.Print("info", fmt.Sprintf("Registering RowQuery callback %v without specify order with Before(), After(), applying Before('gorm:row_query') by default for compatibility...", callbackName))
+			cp.before = "gorm:row_query"
+		}
+	}
+
+	cp.logger.Print("info", fmt.Sprintf("[info] registering callback `%v` from %v", callbackName, fileWithLineNum()))
+	cp.name = callbackName
+	cp.processor = &callback
+	cp.parent.processors = append(cp.parent.processors, cp)
+	cp.parent.reorder()
+}
+
+// Remove a registered callback
+//     db.Callback().Create().Remove("gorm:update_time_stamp_when_create")
+func (cp *CallbackProcessor) Remove(callbackName string) {
+	cp.logger.Print("info", fmt.Sprintf("[info] removing callback `%v` from %v", callbackName, fileWithLineNum()))
+	cp.name = callbackName
+	cp.remove = true
+	cp.parent.processors = append(cp.parent.processors, cp)
+	cp.parent.reorder()
+}
+
+// Replace a registered callback with new callback
+//     db.Callback().Create().Replace("gorm:update_time_stamp_when_create", func(*Scope) {
+//		   scope.SetColumn("CreatedAt", now)
+//		   scope.SetColumn("UpdatedAt", now)
+//     })
+func (cp *CallbackProcessor) Replace(callbackName string, callback func(scope *Scope)) {
+	cp.logger.Print("info", fmt.Sprintf("[info] replacing callback `%v` from %v", callbackName, fileWithLineNum()))
+	cp.name = callbackName
+	cp.processor = &callback
+	cp.replace = true
+	cp.parent.processors = append(cp.parent.processors, cp)
+	cp.parent.reorder()
+}
+
+// Get registered callback
+//    db.Callback().Create().Get("gorm:create")
+func (cp *CallbackProcessor) Get(callbackName string) (callback func(scope *Scope)) {
+	for _, p := range cp.parent.processors {
+		if p.name == callbackName && p.kind == cp.kind {
+			if p.remove {
+				callback = nil
+			} else {
+				callback = *p.processor
+			}
+		}
+	}
+	return
+}
+
+// getRIndex get right index from string slice
+func getRIndex(strs []string, str string) int {
+	for i := len(strs) - 1; i >= 0; i-- {
+		if strs[i] == str {
+			return i
+		}
+	}
+	return -1
+}
+
+// sortProcessors sort callback processors based on its before, after, remove, replace
+func sortProcessors(cps []*CallbackProcessor) []*func(scope *Scope) {
+	var (
+		allNames, sortedNames []string
+		sortCallbackProcessor func(c *CallbackProcessor)
+	)
+
+	for _, cp := range cps {
+		// show warning message the callback name already exists
+		if index := getRIndex(allNames, cp.name); index > -1 && !cp.replace && !cp.remove {
+			cp.logger.Print("warning", fmt.Sprintf("[warning] duplicated callback `%v` from %v", cp.name, fileWithLineNum()))
+		}
+		allNames = append(allNames, cp.name)
+	}
+
+	sortCallbackProcessor = func(c *CallbackProcessor) {
+		if getRIndex(sortedNames, c.name) == -1 { // if not sorted
+			if c.before != "" { // if defined before callback
+				if index := getRIndex(sortedNames, c.before); index != -1 {
+					// if before callback already sorted, append current callback just after it
+					sortedNames = append(sortedNames[:index], append([]string{c.name}, sortedNames[index:]...)...)
+				} else if index := getRIndex(allNames, c.before); index != -1 {
+					// if before callback exists but haven't sorted, append current callback to last
+					sortedNames = append(sortedNames, c.name)
+					sortCallbackProcessor(cps[index])
+				}
+			}
+
+			if c.after != "" { // if defined after callback
+				if index := getRIndex(sortedNames, c.after); index != -1 {
+					// if after callback already sorted, append current callback just before it
+					sortedNames = append(sortedNames[:index+1], append([]string{c.name}, sortedNames[index+1:]...)...)
+				} else if index := getRIndex(allNames, c.after); index != -1 {
+					// if after callback exists but haven't sorted
+					cp := cps[index]
+					// set after callback's before callback to current callback
+					if cp.before == "" {
+						cp.before = c.name
+					}
+					sortCallbackProcessor(cp)
+				}
+			}
+
+			// if current callback haven't been sorted, append it to last
+			if getRIndex(sortedNames, c.name) == -1 {
+				sortedNames = append(sortedNames, c.name)
+			}
+		}
+	}
+
+	for _, cp := range cps {
+		sortCallbackProcessor(cp)
+	}
+
+	var sortedFuncs []*func(scope *Scope)
+	for _, name := range sortedNames {
+		if index := getRIndex(allNames, name); !cps[index].remove {
+			sortedFuncs = append(sortedFuncs, cps[index].processor)
+		}
+	}
+
+	return sortedFuncs
+}
+
+// reorder all registered processors, and reset CRUD callbacks
+func (c *Callback) reorder() {
+	var creates, updates, deletes, queries, rowQueries []*CallbackProcessor
+
+	for _, processor := range c.processors {
+		if processor.name != "" {
+			switch processor.kind {
+			case "create":
+				creates = append(creates, processor)
+			case "update":
+				updates = append(updates, processor)
+			case "delete":
+				deletes = append(deletes, processor)
+			case "query":
+				queries = append(queries, processor)
+			case "row_query":
+				rowQueries = append(rowQueries, processor)
+			}
+		}
+	}
+
+	c.creates = sortProcessors(creates)
+	c.updates = sortProcessors(updates)
+	c.deletes = sortProcessors(deletes)
+	c.queries = sortProcessors(queries)
+	c.rowQueries = sortProcessors(rowQueries)
+}
@@ -0,0 +1,197 @@
+package gorm
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Define callbacks for creating
+func init() {
+	DefaultCallback.Create().Register("gorm:begin_transaction", beginTransactionCallback)
+	DefaultCallback.Create().Register("gorm:before_create", beforeCreateCallback)
+	DefaultCallback.Create().Register("gorm:save_before_associations", saveBeforeAssociationsCallback)
+	DefaultCallback.Create().Register("gorm:update_time_stamp", updateTimeStampForCreateCallback)
+	DefaultCallback.Create().Register("gorm:create", createCallback)
+	DefaultCallback.Create().Register("gorm:force_reload_after_create", forceReloadAfterCreateCallback)
+	DefaultCallback.Create().Register("gorm:save_after_associations", saveAfterAssociationsCallback)
+	DefaultCallback.Create().Register("gorm:after_create", afterCreateCallback)
+	DefaultCallback.Create().Register("gorm:commit_or_rollback_transaction", commitOrRollbackTransactionCallback)
+}
+
+// beforeCreateCallback will invoke `BeforeSave`, `BeforeCreate` method before creating
+func beforeCreateCallback(scope *Scope) {
+	if !scope.HasError() {
+		scope.CallMethod("BeforeSave")
+	}
+	if !scope.HasError() {
+		scope.CallMethod("BeforeCreate")
+	}
+}
+
+// updateTimeStampForCreateCallback will set `CreatedAt`, `UpdatedAt` when creating
+func updateTimeStampForCreateCallback(scope *Scope) {
+	if !scope.HasError() {
+		now := scope.db.nowFunc()
+
+		if createdAtField, ok := scope.FieldByName("CreatedAt"); ok {
+			if createdAtField.IsBlank {
+				createdAtField.Set(now)
+			}
+		}
+
+		if updatedAtField, ok := scope.FieldByName("UpdatedAt"); ok {
+			if updatedAtField.IsBlank {
+				updatedAtField.Set(now)
+			}
+		}
+	}
+}
+
+// createCallback the callback used to insert data into database
+func createCallback(scope *Scope) {
+	if !scope.HasError() {
+		defer scope.trace(NowFunc())
+
+		var (
+			columns, placeholders        []string
+			blankColumnsWithDefaultValue []string
+		)
+
+		for _, field := range scope.Fields() {
+			if scope.changeableField(field) {
+				if field.IsNormal && !field.IsIgnored {
+					if field.IsBlank && field.HasDefaultValue {
+						blankColumnsWithDefaultValue = append(blankColumnsWithDefaultValue, scope.Quote(field.DBName))
+						scope.InstanceSet("gorm:blank_columns_with_default_value", blankColumnsWithDefaultValue)
+					} else if !field.IsPrimaryKey || !field.IsBlank {
+						columns = append(columns, scope.Quote(field.DBName))
+						placeholders = append(placeholders, scope.AddToVars(field.Field.Interface()))
+					}
+				} else if field.Relationship != nil && field.Relationship.Kind == "belongs_to" {
+					for _, foreignKey := range field.Relationship.ForeignDBNames {
+						if foreignField, ok := scope.FieldByName(foreignKey); ok && !scope.changeableField(foreignField) {
+							columns = append(columns, scope.Quote(foreignField.DBName))
+							placeholders = append(placeholders, scope.AddToVars(foreignField.Field.Interface()))
+						}
+					}
+				}
+			}
+		}
+
+		var (
+			returningColumn = "*"
+			quotedTableName = scope.QuotedTableName()
+			primaryField    = scope.PrimaryField()
+			extraOption     string
+			insertModifier  string
+		)
+
+		if str, ok := scope.Get("gorm:insert_option"); ok {
+			extraOption = fmt.Sprint(str)
+		}
+		if str, ok := scope.Get("gorm:insert_modifier"); ok {
+			insertModifier = strings.ToUpper(fmt.Sprint(str))
+			if insertModifier == "INTO" {
+				insertModifier = ""
+			}
+		}
+
+		if primaryField != nil {
+			returningColumn = scope.Quote(primaryField.DBName)
+		}
+
+		lastInsertIDOutputInterstitial := scope.Dialect().LastInsertIDOutputInterstitial(quotedTableName, returningColumn, columns)
+		var lastInsertIDReturningSuffix string
+		if lastInsertIDOutputInterstitial == "" {
+			lastInsertIDReturningSuffix = scope.Dialect().LastInsertIDReturningSuffix(quotedTableName, returningColumn)
+		}
+
+		if len(columns) == 0 {
+			scope.Raw(fmt.Sprintf(
+				"INSERT%v INTO %v %v%v%v",
+				addExtraSpaceIfExist(insertModifier),
+				quotedTableName,
+				scope.Dialect().DefaultValueStr(),
+				addExtraSpaceIfExist(extraOption),
+				addExtraSpaceIfExist(lastInsertIDReturningSuffix),
+			))
+		} else {
+			scope.Raw(fmt.Sprintf(
+				"INSERT%v INTO %v (%v)%v VALUES (%v)%v%v",
+				addExtraSpaceIfExist(insertModifier),
+				scope.QuotedTableName(),
+				strings.Join(columns, ","),
+				addExtraSpaceIfExist(lastInsertIDOutputInterstitial),
+				strings.Join(placeholders, ","),
+				addExtraSpaceIfExist(extraOption),
+				addExtraSpaceIfExist(lastInsertIDReturningSuffix),
+			))
+		}
+
+		// execute create sql: no primaryField
+		if primaryField == nil {
+			if result, err := scope.SQLDB().Exec(scope.SQL, scope.SQLVars...); scope.Err(err) == nil {
+				// set rows affected count
+				scope.db.RowsAffected, _ = result.RowsAffected()
+
+				// set primary value to primary field
+				if primaryField != nil && primaryField.IsBlank {
+					if primaryValue, err := result.LastInsertId(); scope.Err(err) == nil {
+						scope.Err(primaryField.Set(primaryValue))
+					}
+				}
+			}
+			return
+		}
+
+		// execute create sql: lastInsertID implemention for majority of dialects
+		if lastInsertIDReturningSuffix == "" && lastInsertIDOutputInterstitial == "" {
+			if result, err := scope.SQLDB().Exec(scope.SQL, scope.SQLVars...); scope.Err(err) == nil {
+				// set rows affected count
+				scope.db.RowsAffected, _ = result.RowsAffected()
+
+				// set primary value to primary field
+				if primaryField != nil && primaryField.IsBlank {
+					if primaryValue, err := result.LastInsertId(); scope.Err(err) == nil {
+						scope.Err(primaryField.Set(primaryValue))
+					}
+				}
+			}
+			return
+		}
+
+		// execute create sql: dialects with additional lastInsertID requirements (currently postgres & mssql)
+		if primaryField.Field.CanAddr() {
+			if err := scope.SQLDB().QueryRow(scope.SQL, scope.SQLVars...).Scan(primaryField.Field.Addr().Interface()); scope.Err(err) == nil {
+				primaryField.IsBlank = false
+				scope.db.RowsAffected = 1
+			}
+		} else {
+			scope.Err(ErrUnaddressable)
+		}
+		return
+	}
+}
+
+// forceReloadAfterCreateCallback will reload columns that having default value, and set it back to current object
+func forceReloadAfterCreateCallback(scope *Scope) {
+	if blankColumnsWithDefaultValue, ok := scope.InstanceGet("gorm:blank_columns_with_default_value"); ok {
+		db := scope.DB().New().Table(scope.TableName()).Select(blankColumnsWithDefaultValue.([]string))
+		for _, field := range scope.Fields() {
+			if field.IsPrimaryKey && !field.IsBlank {
+				db = db.Where(fmt.Sprintf("%v = ?", field.DBName), field.Field.Interface())
+			}
+		}
+		db.Scan(scope.Value)
+	}
+}
+
+// afterCreateCallback will invoke `AfterCreate`, `AfterSave` method after creating
+func afterCreateCallback(scope *Scope) {
+	if !scope.HasError() {
+		scope.CallMethod("AfterCreate")
+	}
+	if !scope.HasError() {
+		scope.CallMethod("AfterSave")
+	}
+}
@@ -0,0 +1,63 @@
+package gorm
+
+import (
+	"errors"
+	"fmt"
+)
+
+// Define callbacks for deleting
+func init() {
+	DefaultCallback.Delete().Register("gorm:begin_transaction", beginTransactionCallback)
+	DefaultCallback.Delete().Register("gorm:before_delete", beforeDeleteCallback)
+	DefaultCallback.Delete().Register("gorm:delete", deleteCallback)
+	DefaultCallback.Delete().Register("gorm:after_delete", afterDeleteCallback)
+	DefaultCallback.Delete().Register("gorm:commit_or_rollback_transaction", commitOrRollbackTransactionCallback)
+}
+
+// beforeDeleteCallback will invoke `BeforeDelete` method before deleting
+func beforeDeleteCallback(scope *Scope) {
+	if scope.DB().HasBlockGlobalUpdate() && !scope.hasConditions() {
+		scope.Err(errors.New("missing WHERE clause while deleting"))
+		return
+	}
+	if !scope.HasError() {
+		scope.CallMethod("BeforeDelete")
+	}
+}
+
+// deleteCallback used to delete data from database or set deleted_at to current time (when using with soft delete)
+func deleteCallback(scope *Scope) {
+	if !scope.HasError() {
+		var extraOption string
+		if str, ok := scope.Get("gorm:delete_option"); ok {
+			extraOption = fmt.Sprint(str)
+		}
+
+		deletedAtField, hasDeletedAtField := scope.FieldByName("DeletedAt")
+
+		if !scope.Search.Unscoped && hasDeletedAtField {
+			scope.Raw(fmt.Sprintf(
+				"UPDATE %v SET %v=%v%v%v",
+				scope.QuotedTableName(),
+				scope.Quote(deletedAtField.DBName),
+				scope.AddToVars(scope.db.nowFunc()),
+				addExtraSpaceIfExist(scope.CombinedConditionSql()),
+				addExtraSpaceIfExist(extraOption),
+			)).Exec()
+		} else {
+			scope.Raw(fmt.Sprintf(
+				"DELETE FROM %v%v%v",
+				scope.QuotedTableName(),
+				addExtraSpaceIfExist(scope.CombinedConditionSql()),
+				addExtraSpaceIfExist(extraOption),
+			)).Exec()
+		}
+	}
+}
+
+// afterDeleteCallback will invoke `AfterDelete` method after deleting
+func afterDeleteCallback(scope *Scope) {
+	if !scope.HasError() {
+		scope.CallMethod("AfterDelete")
+	}
+}
@@ -0,0 +1,109 @@
+package gorm
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+// Define callbacks for querying
+func init() {
+	DefaultCallback.Query().Register("gorm:query", queryCallback)
+	DefaultCallback.Query().Register("gorm:preload", preloadCallback)
+	DefaultCallback.Query().Register("gorm:after_query", afterQueryCallback)
+}
+
+// queryCallback used to query data from database
+func queryCallback(scope *Scope) {
+	if _, skip := scope.InstanceGet("gorm:skip_query_callback"); skip {
+		return
+	}
+
+	//we are only preloading relations, dont touch base model
+	if _, skip := scope.InstanceGet("gorm:only_preload"); skip {
+		return
+	}
+
+	defer scope.trace(NowFunc())
+
+	var (
+		isSlice, isPtr bool
+		resultType     reflect.Type
+		results        = scope.IndirectValue()
+	)
+
+	if orderBy, ok := scope.Get("gorm:order_by_primary_key"); ok {
+		if primaryField := scope.PrimaryField(); primaryField != nil {
+			scope.Search.Order(fmt.Sprintf("%v.%v %v", scope.QuotedTableName(), scope.Quote(primaryField.DBName), orderBy))
+		}
+	}
+
+	if value, ok := scope.Get("gorm:query_destination"); ok {
+		results = indirect(reflect.ValueOf(value))
+	}
+
+	if kind := results.Kind(); kind == reflect.Slice {
+		isSlice = true
+		resultType = results.Type().Elem()
+		results.Set(reflect.MakeSlice(results.Type(), 0, 0))
+
+		if resultType.Kind() == reflect.Ptr {
+			isPtr = true
+			resultType = resultType.Elem()
+		}
+	} else if kind != reflect.Struct {
+		scope.Err(errors.New("unsupported destination, should be slice or struct"))
+		return
+	}
+
+	scope.prepareQuerySQL()
+
+	if !scope.HasError() {
+		scope.db.RowsAffected = 0
+
+		if str, ok := scope.Get("gorm:query_hint"); ok {
+			scope.SQL = fmt.Sprint(str) + scope.SQL
+		}
+
+		if str, ok := scope.Get("gorm:query_option"); ok {
+			scope.SQL += addExtraSpaceIfExist(fmt.Sprint(str))
+		}
+
+		if rows, err := scope.SQLDB().Query(scope.SQL, scope.SQLVars...); scope.Err(err) == nil {
+			defer rows.Close()
+
+			columns, _ := rows.Columns()
+			for rows.Next() {
+				scope.db.RowsAffected++
+
+				elem := results
+				if isSlice {
+					elem = reflect.New(resultType).Elem()
+				}
+
+				scope.scan(rows, columns, scope.New(elem.Addr().Interface()).Fields())
+
+				if isSlice {
+					if isPtr {
+						results.Set(reflect.Append(results, elem.Addr()))
+					} else {
+						results.Set(reflect.Append(results, elem))
+					}
+				}
+			}
+
+			if err := rows.Err(); err != nil {
+				scope.Err(err)
+			} else if scope.db.RowsAffected == 0 && !isSlice {
+				scope.Err(ErrRecordNotFound)
+			}
+		}
+	}
+}
+
+// afterQueryCallback will invoke `AfterFind` method after querying
+func afterQueryCallback(scope *Scope) {
+	if !scope.HasError() {
+		scope.CallMethod("AfterFind")
+	}
+}
@@ -0,0 +1,410 @@
+package gorm
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+// preloadCallback used to preload associations
+func preloadCallback(scope *Scope) {
+	if _, skip := scope.InstanceGet("gorm:skip_query_callback"); skip {
+		return
+	}
+
+	if ap, ok := scope.Get("gorm:auto_preload"); ok {
+		// If gorm:auto_preload IS NOT a bool then auto preload.
+		// Else if it IS a bool, use the value
+		if apb, ok := ap.(bool); !ok {
+			autoPreload(scope)
+		} else if apb {
+			autoPreload(scope)
+		}
+	}
+
+	if scope.Search.preload == nil || scope.HasError() {
+		return
+	}
+
+	var (
+		preloadedMap = map[string]bool{}
+		fields       = scope.Fields()
+	)
+
+	for _, preload := range scope.Search.preload {
+		var (
+			preloadFields = strings.Split(preload.schema, ".")
+			currentScope  = scope
+			currentFields = fields
+		)
+
+		for idx, preloadField := range preloadFields {
+			var currentPreloadConditions []interface{}
+
+			if currentScope == nil {
+				continue
+			}
+
+			// if not preloaded
+			if preloadKey := strings.Join(preloadFields[:idx+1], "."); !preloadedMap[preloadKey] {
+
+				// assign search conditions to last preload
+				if idx == len(preloadFields)-1 {
+					currentPreloadConditions = preload.conditions
+				}
+
+				for _, field := range currentFields {
+					if field.Name != preloadField || field.Relationship == nil {
+						continue
+					}
+
+					switch field.Relationship.Kind {
+					case "has_one":
+						currentScope.handleHasOnePreload(field, currentPreloadConditions)
+					case "has_many":
+						currentScope.handleHasManyPreload(field, currentPreloadConditions)
+					case "belongs_to":
+						currentScope.handleBelongsToPreload(field, currentPreloadConditions)
+					case "many_to_many":
+						currentScope.handleManyToManyPreload(field, currentPreloadConditions)
+					default:
+						scope.Err(errors.New("unsupported relation"))
+					}
+
+					preloadedMap[preloadKey] = true
+					break
+				}
+
+				if !preloadedMap[preloadKey] {
+					scope.Err(fmt.Errorf("can't preload field %s for %s", preloadField, currentScope.GetModelStruct().ModelType))
+					return
+				}
+			}
+
+			// preload next level
+			if idx < len(preloadFields)-1 {
+				currentScope = currentScope.getColumnAsScope(preloadField)
+				if currentScope != nil {
+					currentFields = currentScope.Fields()
+				}
+			}
+		}
+	}
+}
+
+func autoPreload(scope *Scope) {
+	for _, field := range scope.Fields() {
+		if field.Relationship == nil {
+			continue
+		}
+
+		if val, ok := field.TagSettingsGet("PRELOAD"); ok {
+			if preload, err := strconv.ParseBool(val); err != nil {
+				scope.Err(errors.New("invalid preload option"))
+				return
+			} else if !preload {
+				continue
+			}
+		}
+
+		scope.Search.Preload(field.Name)
+	}
+}
+
+func (scope *Scope) generatePreloadDBWithConditions(conditions []interface{}) (*DB, []interface{}) {
+	var (
+		preloadDB         = scope.NewDB()
+		preloadConditions []interface{}
+	)
+
+	for _, condition := range conditions {
+		if scopes, ok := condition.(func(*DB) *DB); ok {
+			preloadDB = scopes(preloadDB)
+		} else {
+			preloadConditions = append(preloadConditions, condition)
+		}
+	}
+
+	return preloadDB, preloadConditions
+}
+
+// handleHasOnePreload used to preload has one associations
+func (scope *Scope) handleHasOnePreload(field *Field, conditions []interface{}) {
+	relation := field.Relationship
+
+	// get relations's primary keys
+	primaryKeys := scope.getColumnAsArray(relation.AssociationForeignFieldNames, scope.Value)
+	if len(primaryKeys) == 0 {
+		return
+	}
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// find relations
+	query := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.ForeignDBNames), toQueryMarks(primaryKeys))
+	values := toQueryValues(primaryKeys)
+	if relation.PolymorphicType != "" {
+		query += fmt.Sprintf(" AND %v = ?", scope.Quote(relation.PolymorphicDBName))
+		values = append(values, relation.PolymorphicValue)
+	}
+
+	results := makeSlice(field.Struct.Type)
+	scope.Err(preloadDB.Where(query, values...).Find(results, preloadConditions...).Error)
+
+	// assign find results
+	var (
+		resultsValue       = indirect(reflect.ValueOf(results))
+		indirectScopeValue = scope.IndirectValue()
+	)
+
+	if indirectScopeValue.Kind() == reflect.Slice {
+		foreignValuesToResults := make(map[string]reflect.Value)
+		for i := 0; i < resultsValue.Len(); i++ {
+			result := resultsValue.Index(i)
+			foreignValues := toString(getValueFromFields(result, relation.ForeignFieldNames))
+			foreignValuesToResults[foreignValues] = result
+		}
+		for j := 0; j < indirectScopeValue.Len(); j++ {
+			indirectValue := indirect(indirectScopeValue.Index(j))
+			valueString := toString(getValueFromFields(indirectValue, relation.AssociationForeignFieldNames))
+			if result, found := foreignValuesToResults[valueString]; found {
+				indirectValue.FieldByName(field.Name).Set(result)
+			}
+		}
+	} else {
+		for i := 0; i < resultsValue.Len(); i++ {
+			result := resultsValue.Index(i)
+			scope.Err(field.Set(result))
+		}
+	}
+}
+
+// handleHasManyPreload used to preload has many associations
+func (scope *Scope) handleHasManyPreload(field *Field, conditions []interface{}) {
+	relation := field.Relationship
+
+	// get relations's primary keys
+	primaryKeys := scope.getColumnAsArray(relation.AssociationForeignFieldNames, scope.Value)
+	if len(primaryKeys) == 0 {
+		return
+	}
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// find relations
+	query := fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.ForeignDBNames), toQueryMarks(primaryKeys))
+	values := toQueryValues(primaryKeys)
+	if relation.PolymorphicType != "" {
+		query += fmt.Sprintf(" AND %v = ?", scope.Quote(relation.PolymorphicDBName))
+		values = append(values, relation.PolymorphicValue)
+	}
+
+	results := makeSlice(field.Struct.Type)
+	scope.Err(preloadDB.Where(query, values...).Find(results, preloadConditions...).Error)
+
+	// assign find results
+	var (
+		resultsValue       = indirect(reflect.ValueOf(results))
+		indirectScopeValue = scope.IndirectValue()
+	)
+
+	if indirectScopeValue.Kind() == reflect.Slice {
+		preloadMap := make(map[string][]reflect.Value)
+		for i := 0; i < resultsValue.Len(); i++ {
+			result := resultsValue.Index(i)
+			foreignValues := getValueFromFields(result, relation.ForeignFieldNames)
+			preloadMap[toString(foreignValues)] = append(preloadMap[toString(foreignValues)], result)
+		}
+
+		for j := 0; j < indirectScopeValue.Len(); j++ {
+			object := indirect(indirectScopeValue.Index(j))
+			objectRealValue := getValueFromFields(object, relation.AssociationForeignFieldNames)
+			f := object.FieldByName(field.Name)
+			if results, ok := preloadMap[toString(objectRealValue)]; ok {
+				f.Set(reflect.Append(f, results...))
+			} else {
+				f.Set(reflect.MakeSlice(f.Type(), 0, 0))
+			}
+		}
+	} else {
+		scope.Err(field.Set(resultsValue))
+	}
+}
+
+// handleBelongsToPreload used to preload belongs to associations
+func (scope *Scope) handleBelongsToPreload(field *Field, conditions []interface{}) {
+	relation := field.Relationship
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// get relations's primary keys
+	primaryKeys := scope.getColumnAsArray(relation.ForeignFieldNames, scope.Value)
+	if len(primaryKeys) == 0 {
+		return
+	}
+
+	// find relations
+	results := makeSlice(field.Struct.Type)
+	scope.Err(preloadDB.Where(fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relation.AssociationForeignDBNames), toQueryMarks(primaryKeys)), toQueryValues(primaryKeys)...).Find(results, preloadConditions...).Error)
+
+	// assign find results
+	var (
+		resultsValue       = indirect(reflect.ValueOf(results))
+		indirectScopeValue = scope.IndirectValue()
+	)
+
+	foreignFieldToObjects := make(map[string][]*reflect.Value)
+	if indirectScopeValue.Kind() == reflect.Slice {
+		for j := 0; j < indirectScopeValue.Len(); j++ {
+			object := indirect(indirectScopeValue.Index(j))
+			valueString := toString(getValueFromFields(object, relation.ForeignFieldNames))
+			foreignFieldToObjects[valueString] = append(foreignFieldToObjects[valueString], &object)
+		}
+	}
+
+	for i := 0; i < resultsValue.Len(); i++ {
+		result := resultsValue.Index(i)
+		if indirectScopeValue.Kind() == reflect.Slice {
+			valueString := toString(getValueFromFields(result, relation.AssociationForeignFieldNames))
+			if objects, found := foreignFieldToObjects[valueString]; found {
+				for _, object := range objects {
+					object.FieldByName(field.Name).Set(result)
+				}
+			}
+		} else {
+			scope.Err(field.Set(result))
+		}
+	}
+}
+
+// handleManyToManyPreload used to preload many to many associations
+func (scope *Scope) handleManyToManyPreload(field *Field, conditions []interface{}) {
+	var (
+		relation         = field.Relationship
+		joinTableHandler = relation.JoinTableHandler
+		fieldType        = field.Struct.Type.Elem()
+		foreignKeyValue  interface{}
+		foreignKeyType   = reflect.ValueOf(&foreignKeyValue).Type()
+		linkHash         = map[string][]reflect.Value{}
+		isPtr            bool
+	)
+
+	if fieldType.Kind() == reflect.Ptr {
+		isPtr = true
+		fieldType = fieldType.Elem()
+	}
+
+	var sourceKeys = []string{}
+	for _, key := range joinTableHandler.SourceForeignKeys() {
+		sourceKeys = append(sourceKeys, key.DBName)
+	}
+
+	// preload conditions
+	preloadDB, preloadConditions := scope.generatePreloadDBWithConditions(conditions)
+
+	// generate query with join table
+	newScope := scope.New(reflect.New(fieldType).Interface())
+	preloadDB = preloadDB.Table(newScope.TableName()).Model(newScope.Value)
+
+	if len(preloadDB.search.selects) == 0 {
+		preloadDB = preloadDB.Select("*")
+	}
+
+	preloadDB = joinTableHandler.JoinWith(joinTableHandler, preloadDB, scope.Value)
+
+	// preload inline conditions
+	if len(preloadConditions) > 0 {
+		preloadDB = preloadDB.Where(preloadConditions[0], preloadConditions[1:]...)
+	}
+
+	rows, err := preloadDB.Rows()
+
+	if scope.Err(err) != nil {
+		return
+	}
+	defer rows.Close()
+
+	columns, _ := rows.Columns()
+	for rows.Next() {
+		var (
+			elem   = reflect.New(fieldType).Elem()
+			fields = scope.New(elem.Addr().Interface()).Fields()
+		)
+
+		// register foreign keys in join tables
+		var joinTableFields []*Field
+		for _, sourceKey := range sourceKeys {
+			joinTableFields = append(joinTableFields, &Field{StructField: &StructField{DBName: sourceKey, IsNormal: true}, Field: reflect.New(foreignKeyType).Elem()})
+		}
+
+		scope.scan(rows, columns, append(fields, joinTableFields...))
+
+		scope.New(elem.Addr().Interface()).
+			InstanceSet("gorm:skip_query_callback", true).
+			callCallbacks(scope.db.parent.callbacks.queries)
+
+		var foreignKeys = make([]interface{}, len(sourceKeys))
+		// generate hashed forkey keys in join table
+		for idx, joinTableField := range joinTableFields {
+			if !joinTableField.Field.IsNil() {
+				foreignKeys[idx] = joinTableField.Field.Elem().Interface()
+			}
+		}
+		hashedSourceKeys := toString(foreignKeys)
+
+		if isPtr {
+			linkHash[hashedSourceKeys] = append(linkHash[hashedSourceKeys], elem.Addr())
+		} else {
+			linkHash[hashedSourceKeys] = append(linkHash[hashedSourceKeys], elem)
+		}
+	}
+
+	if err := rows.Err(); err != nil {
+		scope.Err(err)
+	}
+
+	// assign find results
+	var (
+		indirectScopeValue = scope.IndirectValue()
+		fieldsSourceMap    = map[string][]reflect.Value{}
+		foreignFieldNames  = []string{}
+	)
+
+	for _, dbName := range relation.ForeignFieldNames {
+		if field, ok := scope.FieldByName(dbName); ok {
+			foreignFieldNames = append(foreignFieldNames, field.Name)
+		}
+	}
+
+	if indirectScopeValue.Kind() == reflect.Slice {
+		for j := 0; j < indirectScopeValue.Len(); j++ {
+			object := indirect(indirectScopeValue.Index(j))
+			key := toString(getValueFromFields(object, foreignFieldNames))
+			fieldsSourceMap[key] = append(fieldsSourceMap[key], object.FieldByName(field.Name))
+		}
+	} else if indirectScopeValue.IsValid() {
+		key := toString(getValueFromFields(indirectScopeValue, foreignFieldNames))
+		fieldsSourceMap[key] = append(fieldsSourceMap[key], indirectScopeValue.FieldByName(field.Name))
+	}
+
+	for source, fields := range fieldsSourceMap {
+		for _, f := range fields {
+			//If not 0 this means Value is a pointer and we already added preloaded models to it
+			if f.Len() != 0 {
+				continue
+			}
+
+			v := reflect.MakeSlice(f.Type(), 0, 0)
+			if len(linkHash[source]) > 0 {
+				v = reflect.Append(f, linkHash[source]...)
+			}
+
+			f.Set(v)
+		}
+	}
+}
@@ -0,0 +1,41 @@
+package gorm
+
+import (
+	"database/sql"
+	"fmt"
+)
+
+// Define callbacks for row query
+func init() {
+	DefaultCallback.RowQuery().Register("gorm:row_query", rowQueryCallback)
+}
+
+type RowQueryResult struct {
+	Row *sql.Row
+}
+
+type RowsQueryResult struct {
+	Rows  *sql.Rows
+	Error error
+}
+
+// queryCallback used to query data from database
+func rowQueryCallback(scope *Scope) {
+	if result, ok := scope.InstanceGet("row_query_result"); ok {
+		scope.prepareQuerySQL()
+
+		if str, ok := scope.Get("gorm:query_hint"); ok {
+			scope.SQL = fmt.Sprint(str) + scope.SQL
+		}
+
+		if str, ok := scope.Get("gorm:query_option"); ok {
+			scope.SQL += addExtraSpaceIfExist(fmt.Sprint(str))
+		}
+
+		if rowResult, ok := result.(*RowQueryResult); ok {
+			rowResult.Row = scope.SQLDB().QueryRow(scope.SQL, scope.SQLVars...)
+		} else if rowsResult, ok := result.(*RowsQueryResult); ok {
+			rowsResult.Rows, rowsResult.Error = scope.SQLDB().Query(scope.SQL, scope.SQLVars...)
+		}
+	}
+}
@@ -0,0 +1,170 @@
+package gorm
+
+import (
+	"reflect"
+	"strings"
+)
+
+func beginTransactionCallback(scope *Scope) {
+	scope.Begin()
+}
+
+func commitOrRollbackTransactionCallback(scope *Scope) {
+	scope.CommitOrRollback()
+}
+
+func saveAssociationCheck(scope *Scope, field *Field) (autoUpdate bool, autoCreate bool, saveReference bool, r *Relationship) {
+	checkTruth := func(value interface{}) bool {
+		if v, ok := value.(bool); ok && !v {
+			return false
+		}
+
+		if v, ok := value.(string); ok {
+			v = strings.ToLower(v)
+			return v == "true"
+		}
+
+		return true
+	}
+
+	if scope.changeableField(field) && !field.IsBlank && !field.IsIgnored {
+		if r = field.Relationship; r != nil {
+			autoUpdate, autoCreate, saveReference = true, true, true
+
+			if value, ok := scope.Get("gorm:save_associations"); ok {
+				autoUpdate = checkTruth(value)
+				autoCreate = autoUpdate
+				saveReference = autoUpdate
+			} else if value, ok := field.TagSettingsGet("SAVE_ASSOCIATIONS"); ok {
+				autoUpdate = checkTruth(value)
+				autoCreate = autoUpdate
+				saveReference = autoUpdate
+			}
+
+			if value, ok := scope.Get("gorm:association_autoupdate"); ok {
+				autoUpdate = checkTruth(value)
+			} else if value, ok := field.TagSettingsGet("ASSOCIATION_AUTOUPDATE"); ok {
+				autoUpdate = checkTruth(value)
+			}
+
+			if value, ok := scope.Get("gorm:association_autocreate"); ok {
+				autoCreate = checkTruth(value)
+			} else if value, ok := field.TagSettingsGet("ASSOCIATION_AUTOCREATE"); ok {
+				autoCreate = checkTruth(value)
+			}
+
+			if value, ok := scope.Get("gorm:association_save_reference"); ok {
+				saveReference = checkTruth(value)
+			} else if value, ok := field.TagSettingsGet("ASSOCIATION_SAVE_REFERENCE"); ok {
+				saveReference = checkTruth(value)
+			}
+		}
+	}
+
+	return
+}
+
+func saveBeforeAssociationsCallback(scope *Scope) {
+	for _, field := range scope.Fields() {
+		autoUpdate, autoCreate, saveReference, relationship := saveAssociationCheck(scope, field)
+
+		if relationship != nil && relationship.Kind == "belongs_to" {
+			fieldValue := field.Field.Addr().Interface()
+			newScope := scope.New(fieldValue)
+
+			if newScope.PrimaryKeyZero() {
+				if autoCreate {
+					scope.Err(scope.NewDB().Save(fieldValue).Error)
+				}
+			} else if autoUpdate {
+				scope.Err(scope.NewDB().Save(fieldValue).Error)
+			}
+
+			if saveReference {
+				if len(relationship.ForeignFieldNames) != 0 {
+					// set value's foreign key
+					for idx, fieldName := range relationship.ForeignFieldNames {
+						associationForeignName := relationship.AssociationForeignDBNames[idx]
+						if foreignField, ok := scope.New(fieldValue).FieldByName(associationForeignName); ok {
+							scope.Err(scope.SetColumn(fieldName, foreignField.Field.Interface()))
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+func saveAfterAssociationsCallback(scope *Scope) {
+	for _, field := range scope.Fields() {
+		autoUpdate, autoCreate, saveReference, relationship := saveAssociationCheck(scope, field)
+
+		if relationship != nil && (relationship.Kind == "has_one" || relationship.Kind == "has_many" || relationship.Kind == "many_to_many") {
+			value := field.Field
+
+			switch value.Kind() {
+			case reflect.Slice:
+				for i := 0; i < value.Len(); i++ {
+					newDB := scope.NewDB()
+					elem := value.Index(i).Addr().Interface()
+					newScope := newDB.NewScope(elem)
+
+					if saveReference {
+						if relationship.JoinTableHandler == nil && len(relationship.ForeignFieldNames) != 0 {
+							for idx, fieldName := range relationship.ForeignFieldNames {
+								associationForeignName := relationship.AssociationForeignDBNames[idx]
+								if f, ok := scope.FieldByName(associationForeignName); ok {
+									scope.Err(newScope.SetColumn(fieldName, f.Field.Interface()))
+								}
+							}
+						}
+
+						if relationship.PolymorphicType != "" {
+							scope.Err(newScope.SetColumn(relationship.PolymorphicType, relationship.PolymorphicValue))
+						}
+					}
+
+					if newScope.PrimaryKeyZero() {
+						if autoCreate {
+							scope.Err(newDB.Save(elem).Error)
+						}
+					} else if autoUpdate {
+						scope.Err(newDB.Save(elem).Error)
+					}
+
+					if !scope.New(newScope.Value).PrimaryKeyZero() && saveReference {
+						if joinTableHandler := relationship.JoinTableHandler; joinTableHandler != nil {
+							scope.Err(joinTableHandler.Add(joinTableHandler, newDB, scope.Value, newScope.Value))
+						}
+					}
+				}
+			default:
+				elem := value.Addr().Interface()
+				newScope := scope.New(elem)
+
+				if saveReference {
+					if len(relationship.ForeignFieldNames) != 0 {
+						for idx, fieldName := range relationship.ForeignFieldNames {
+							associationForeignName := relationship.AssociationForeignDBNames[idx]
+							if f, ok := scope.FieldByName(associationForeignName); ok {
+								scope.Err(newScope.SetColumn(fieldName, f.Field.Interface()))
+							}
+						}
+					}
+
+					if relationship.PolymorphicType != "" {
+						scope.Err(newScope.SetColumn(relationship.PolymorphicType, relationship.PolymorphicValue))
+					}
+				}
+
+				if newScope.PrimaryKeyZero() {
+					if autoCreate {
+						scope.Err(scope.NewDB().Save(elem).Error)
+					}
+				} else if autoUpdate {
+					scope.Err(scope.NewDB().Save(elem).Error)
+				}
+			}
+		}
+	}
+}
@@ -0,0 +1,121 @@
+package gorm
+
+import (
+	"errors"
+	"fmt"
+	"sort"
+	"strings"
+)
+
+// Define callbacks for updating
+func init() {
+	DefaultCallback.Update().Register("gorm:assign_updating_attributes", assignUpdatingAttributesCallback)
+	DefaultCallback.Update().Register("gorm:begin_transaction", beginTransactionCallback)
+	DefaultCallback.Update().Register("gorm:before_update", beforeUpdateCallback)
+	DefaultCallback.Update().Register("gorm:save_before_associations", saveBeforeAssociationsCallback)
+	DefaultCallback.Update().Register("gorm:update_time_stamp", updateTimeStampForUpdateCallback)
+	DefaultCallback.Update().Register("gorm:update", updateCallback)
+	DefaultCallback.Update().Register("gorm:save_after_associations", saveAfterAssociationsCallback)
+	DefaultCallback.Update().Register("gorm:after_update", afterUpdateCallback)
+	DefaultCallback.Update().Register("gorm:commit_or_rollback_transaction", commitOrRollbackTransactionCallback)
+}
+
+// assignUpdatingAttributesCallback assign updating attributes to model
+func assignUpdatingAttributesCallback(scope *Scope) {
+	if attrs, ok := scope.InstanceGet("gorm:update_interface"); ok {
+		if updateMaps, hasUpdate := scope.updatedAttrsWithValues(attrs); hasUpdate {
+			scope.InstanceSet("gorm:update_attrs", updateMaps)
+		} else {
+			scope.SkipLeft()
+		}
+	}
+}
+
+// beforeUpdateCallback will invoke `BeforeSave`, `BeforeUpdate` method before updating
+func beforeUpdateCallback(scope *Scope) {
+	if scope.DB().HasBlockGlobalUpdate() && !scope.hasConditions() {
+		scope.Err(errors.New("missing WHERE clause while updating"))
+		return
+	}
+	if _, ok := scope.Get("gorm:update_column"); !ok {
+		if !scope.HasError() {
+			scope.CallMethod("BeforeSave")
+		}
+		if !scope.HasError() {
+			scope.CallMethod("BeforeUpdate")
+		}
+	}
+}
+
+// updateTimeStampForUpdateCallback will set `UpdatedAt` when updating
+func updateTimeStampForUpdateCallback(scope *Scope) {
+	if _, ok := scope.Get("gorm:update_column"); !ok {
+		scope.SetColumn("UpdatedAt", scope.db.nowFunc())
+	}
+}
+
+// updateCallback the callback used to update data to database
+func updateCallback(scope *Scope) {
+	if !scope.HasError() {
+		var sqls []string
+
+		if updateAttrs, ok := scope.InstanceGet("gorm:update_attrs"); ok {
+			// Sort the column names so that the generated SQL is the same every time.
+			updateMap := updateAttrs.(map[string]interface{})
+			var columns []string
+			for c := range updateMap {
+				columns = append(columns, c)
+			}
+			sort.Strings(columns)
+
+			for _, column := range columns {
+				value := updateMap[column]
+				sqls = append(sqls, fmt.Sprintf("%v = %v", scope.Quote(column), scope.AddToVars(value)))
+			}
+		} else {
+			for _, field := range scope.Fields() {
+				if scope.changeableField(field) {
+					if !field.IsPrimaryKey && field.IsNormal && (field.Name != "CreatedAt" || !field.IsBlank) {
+						if !field.IsForeignKey || !field.IsBlank || !field.HasDefaultValue {
+							sqls = append(sqls, fmt.Sprintf("%v = %v", scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface())))
+						}
+					} else if relationship := field.Relationship; relationship != nil && relationship.Kind == "belongs_to" {
+						for _, foreignKey := range relationship.ForeignDBNames {
+							if foreignField, ok := scope.FieldByName(foreignKey); ok && !scope.changeableField(foreignField) {
+								sqls = append(sqls,
+									fmt.Sprintf("%v = %v", scope.Quote(foreignField.DBName), scope.AddToVars(foreignField.Field.Interface())))
+							}
+						}
+					}
+				}
+			}
+		}
+
+		var extraOption string
+		if str, ok := scope.Get("gorm:update_option"); ok {
+			extraOption = fmt.Sprint(str)
+		}
+
+		if len(sqls) > 0 {
+			scope.Raw(fmt.Sprintf(
+				"UPDATE %v SET %v%v%v",
+				scope.QuotedTableName(),
+				strings.Join(sqls, ", "),
+				addExtraSpaceIfExist(scope.CombinedConditionSql()),
+				addExtraSpaceIfExist(extraOption),
+			)).Exec()
+		}
+	}
+}
+
+// afterUpdateCallback will invoke `AfterUpdate`, `AfterSave` method after updating
+func afterUpdateCallback(scope *Scope) {
+	if _, ok := scope.Get("gorm:update_column"); !ok {
+		if !scope.HasError() {
+			scope.CallMethod("AfterUpdate")
+		}
+		if !scope.HasError() {
+			scope.CallMethod("AfterSave")
+		}
+	}
+}
@@ -0,0 +1,147 @@
+package gorm
+
+import (
+	"database/sql"
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+// Dialect interface contains behaviors that differ across SQL database
+type Dialect interface {
+	// GetName get dialect's name
+	GetName() string
+
+	// SetDB set db for dialect
+	SetDB(db SQLCommon)
+
+	// BindVar return the placeholder for actual values in SQL statements, in many dbs it is "?", Postgres using $1
+	BindVar(i int) string
+	// Quote quotes field name to avoid SQL parsing exceptions by using a reserved word as a field name
+	Quote(key string) string
+	// DataTypeOf return data's sql type
+	DataTypeOf(field *StructField) string
+
+	// HasIndex check has index or not
+	HasIndex(tableName string, indexName string) bool
+	// HasForeignKey check has foreign key or not
+	HasForeignKey(tableName string, foreignKeyName string) bool
+	// RemoveIndex remove index
+	RemoveIndex(tableName string, indexName string) error
+	// HasTable check has table or not
+	HasTable(tableName string) bool
+	// HasColumn check has column or not
+	HasColumn(tableName string, columnName string) bool
+	// ModifyColumn modify column's type
+	ModifyColumn(tableName string, columnName string, typ string) error
+
+	// LimitAndOffsetSQL return generated SQL with Limit and Offset, as mssql has special case
+	LimitAndOffsetSQL(limit, offset interface{}) (string, error)
+	// SelectFromDummyTable return select values, for most dbs, `SELECT values` just works, mysql needs `SELECT value FROM DUAL`
+	SelectFromDummyTable() string
+	// LastInsertIDOutputInterstitial most dbs support LastInsertId, but mssql needs to use `OUTPUT`
+	LastInsertIDOutputInterstitial(tableName, columnName string, columns []string) string
+	// LastInsertIdReturningSuffix most dbs support LastInsertId, but postgres needs to use `RETURNING`
+	LastInsertIDReturningSuffix(tableName, columnName string) string
+	// DefaultValueStr
+	DefaultValueStr() string
+
+	// BuildKeyName returns a valid key name (foreign key, index key) for the given table, field and reference
+	BuildKeyName(kind, tableName string, fields ...string) string
+
+	// NormalizeIndexAndColumn returns valid index name and column name depending on each dialect
+	NormalizeIndexAndColumn(indexName, columnName string) (string, string)
+
+	// CurrentDatabase return current database name
+	CurrentDatabase() string
+}
+
+var dialectsMap = map[string]Dialect{}
+
+func newDialect(name string, db SQLCommon) Dialect {
+	if value, ok := dialectsMap[name]; ok {
+		dialect := reflect.New(reflect.TypeOf(value).Elem()).Interface().(Dialect)
+		dialect.SetDB(db)
+		return dialect
+	}
+
+	fmt.Printf("`%v` is not officially supported, running under compatibility mode.\n", name)
+	commontDialect := &commonDialect{}
+	commontDialect.SetDB(db)
+	return commontDialect
+}
+
+// RegisterDialect register new dialect
+func RegisterDialect(name string, dialect Dialect) {
+	dialectsMap[name] = dialect
+}
+
+// GetDialect gets the dialect for the specified dialect name
+func GetDialect(name string) (dialect Dialect, ok bool) {
+	dialect, ok = dialectsMap[name]
+	return
+}
+
+// ParseFieldStructForDialect get field's sql data type
+var ParseFieldStructForDialect = func(field *StructField, dialect Dialect) (fieldValue reflect.Value, sqlType string, size int, additionalType string) {
+	// Get redirected field type
+	var (
+		reflectType = field.Struct.Type
+		dataType, _ = field.TagSettingsGet("TYPE")
+	)
+
+	for reflectType.Kind() == reflect.Ptr {
+		reflectType = reflectType.Elem()
+	}
+
+	// Get redirected field value
+	fieldValue = reflect.Indirect(reflect.New(reflectType))
+
+	if gormDataType, ok := fieldValue.Interface().(interface {
+		GormDataType(Dialect) string
+	}); ok {
+		dataType = gormDataType.GormDataType(dialect)
+	}
+
+	// Get scanner's real value
+	if dataType == "" {
+		var getScannerValue func(reflect.Value)
+		getScannerValue = func(value reflect.Value) {
+			fieldValue = value
+			if _, isScanner := reflect.New(fieldValue.Type()).Interface().(sql.Scanner); isScanner && fieldValue.Kind() == reflect.Struct {
+				getScannerValue(fieldValue.Field(0))
+			}
+		}
+		getScannerValue(fieldValue)
+	}
+
+	// Default Size
+	if num, ok := field.TagSettingsGet("SIZE"); ok {
+		size, _ = strconv.Atoi(num)
+	} else {
+		size = 255
+	}
+
+	// Default type from tag setting
+	notNull, _ := field.TagSettingsGet("NOT NULL")
+	unique, _ := field.TagSettingsGet("UNIQUE")
+	additionalType = notNull + " " + unique
+	if value, ok := field.TagSettingsGet("DEFAULT"); ok {
+		additionalType = additionalType + " DEFAULT " + value
+	}
+
+	if value, ok := field.TagSettingsGet("COMMENT"); ok {
+		additionalType = additionalType + " COMMENT " + value
+	}
+
+	return fieldValue, dataType, size, strings.TrimSpace(additionalType)
+}
+
+func currentDatabaseAndTable(dialect Dialect, tableName string) (string, string) {
+	if strings.Contains(tableName, ".") {
+		splitStrings := strings.SplitN(tableName, ".", 2)
+		return splitStrings[0], splitStrings[1]
+	}
+	return dialect.CurrentDatabase(), tableName
+}
@@ -0,0 +1,196 @@
+package gorm
+
+import (
+	"fmt"
+	"reflect"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var keyNameRegex = regexp.MustCompile("[^a-zA-Z0-9]+")
+
+// DefaultForeignKeyNamer contains the default foreign key name generator method
+type DefaultForeignKeyNamer struct {
+}
+
+type commonDialect struct {
+	db SQLCommon
+	DefaultForeignKeyNamer
+}
+
+func init() {
+	RegisterDialect("common", &commonDialect{})
+}
+
+func (commonDialect) GetName() string {
+	return "common"
+}
+
+func (s *commonDialect) SetDB(db SQLCommon) {
+	s.db = db
+}
+
+func (commonDialect) BindVar(i int) string {
+	return "$$$" // ?
+}
+
+func (commonDialect) Quote(key string) string {
+	return fmt.Sprintf(`"%s"`, key)
+}
+
+func (s *commonDialect) fieldCanAutoIncrement(field *StructField) bool {
+	if value, ok := field.TagSettingsGet("AUTO_INCREMENT"); ok {
+		return strings.ToLower(value) != "false"
+	}
+	return field.IsPrimaryKey
+}
+
+func (s *commonDialect) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field, s)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "BOOLEAN"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if s.fieldCanAutoIncrement(field) {
+				sqlType = "INTEGER AUTO_INCREMENT"
+			} else {
+				sqlType = "INTEGER"
+			}
+		case reflect.Int64, reflect.Uint64:
+			if s.fieldCanAutoIncrement(field) {
+				sqlType = "BIGINT AUTO_INCREMENT"
+			} else {
+				sqlType = "BIGINT"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "FLOAT"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("VARCHAR(%d)", size)
+			} else {
+				sqlType = "VARCHAR(65532)"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "TIMESTAMP"
+			}
+		default:
+			if _, ok := dataValue.Interface().([]byte); ok {
+				if size > 0 && size < 65532 {
+					sqlType = fmt.Sprintf("BINARY(%d)", size)
+				} else {
+					sqlType = "BINARY(65532)"
+				}
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for commonDialect", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s commonDialect) HasIndex(tableName string, indexName string) bool {
+	var count int
+	currentDatabase, tableName := currentDatabaseAndTable(&s, tableName)
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.STATISTICS WHERE table_schema = ? AND table_name = ? AND index_name = ?", currentDatabase, tableName, indexName).Scan(&count)
+	return count > 0
+}
+
+func (s commonDialect) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v", indexName))
+	return err
+}
+
+func (s commonDialect) HasForeignKey(tableName string, foreignKeyName string) bool {
+	return false
+}
+
+func (s commonDialect) HasTable(tableName string) bool {
+	var count int
+	currentDatabase, tableName := currentDatabaseAndTable(&s, tableName)
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = ? AND table_name = ?", currentDatabase, tableName).Scan(&count)
+	return count > 0
+}
+
+func (s commonDialect) HasColumn(tableName string, columnName string) bool {
+	var count int
+	currentDatabase, tableName := currentDatabaseAndTable(&s, tableName)
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE table_schema = ? AND table_name = ? AND column_name = ?", currentDatabase, tableName, columnName).Scan(&count)
+	return count > 0
+}
+
+func (s commonDialect) ModifyColumn(tableName string, columnName string, typ string) error {
+	_, err := s.db.Exec(fmt.Sprintf("ALTER TABLE %v ALTER COLUMN %v TYPE %v", tableName, columnName, typ))
+	return err
+}
+
+func (s commonDialect) CurrentDatabase() (name string) {
+	s.db.QueryRow("SELECT DATABASE()").Scan(&name)
+	return
+}
+
+// LimitAndOffsetSQL return generated SQL with Limit and Offset
+func (s commonDialect) LimitAndOffsetSQL(limit, offset interface{}) (sql string, err error) {
+	if limit != nil {
+		if parsedLimit, err := s.parseInt(limit); err != nil {
+			return "", err
+		} else if parsedLimit >= 0 {
+			sql += fmt.Sprintf(" LIMIT %d", parsedLimit)
+		}
+	}
+	if offset != nil {
+		if parsedOffset, err := s.parseInt(offset); err != nil {
+			return "", err
+		} else if parsedOffset >= 0 {
+			sql += fmt.Sprintf(" OFFSET %d", parsedOffset)
+		}
+	}
+	return
+}
+
+func (commonDialect) SelectFromDummyTable() string {
+	return ""
+}
+
+func (commonDialect) LastInsertIDOutputInterstitial(tableName, columnName string, columns []string) string {
+	return ""
+}
+
+func (commonDialect) LastInsertIDReturningSuffix(tableName, columnName string) string {
+	return ""
+}
+
+func (commonDialect) DefaultValueStr() string {
+	return "DEFAULT VALUES"
+}
+
+// BuildKeyName returns a valid key name (foreign key, index key) for the given table, field and reference
+func (DefaultForeignKeyNamer) BuildKeyName(kind, tableName string, fields ...string) string {
+	keyName := fmt.Sprintf("%s_%s_%s", kind, tableName, strings.Join(fields, "_"))
+	keyName = keyNameRegex.ReplaceAllString(keyName, "_")
+	return keyName
+}
+
+// NormalizeIndexAndColumn returns argument's index name and column name without doing anything
+func (commonDialect) NormalizeIndexAndColumn(indexName, columnName string) (string, string) {
+	return indexName, columnName
+}
+
+func (commonDialect) parseInt(value interface{}) (int64, error) {
+	return strconv.ParseInt(fmt.Sprint(value), 0, 0)
+}
+
+// IsByteArrayOrSlice returns true of the reflected value is an array or slice
+func IsByteArrayOrSlice(value reflect.Value) bool {
+	return (value.Kind() == reflect.Array || value.Kind() == reflect.Slice) && value.Type().Elem() == reflect.TypeOf(uint8(0))
+}
@@ -0,0 +1,246 @@
+package gorm
+
+import (
+	"crypto/sha1"
+	"database/sql"
+	"fmt"
+	"reflect"
+	"regexp"
+	"strings"
+	"time"
+	"unicode/utf8"
+)
+
+var mysqlIndexRegex = regexp.MustCompile(`^(.+)\((\d+)\)$`)
+
+type mysql struct {
+	commonDialect
+}
+
+func init() {
+	RegisterDialect("mysql", &mysql{})
+}
+
+func (mysql) GetName() string {
+	return "mysql"
+}
+
+func (mysql) Quote(key string) string {
+	return fmt.Sprintf("`%s`", key)
+}
+
+// Get Data Type for MySQL Dialect
+func (s *mysql) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field, s)
+
+	// MySQL allows only one auto increment column per table, and it must
+	// be a KEY column.
+	if _, ok := field.TagSettingsGet("AUTO_INCREMENT"); ok {
+		if _, ok = field.TagSettingsGet("INDEX"); !ok && !field.IsPrimaryKey {
+			field.TagSettingsDelete("AUTO_INCREMENT")
+		}
+	}
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "boolean"
+		case reflect.Int8:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "tinyint AUTO_INCREMENT"
+			} else {
+				sqlType = "tinyint"
+			}
+		case reflect.Int, reflect.Int16, reflect.Int32:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "int AUTO_INCREMENT"
+			} else {
+				sqlType = "int"
+			}
+		case reflect.Uint8:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "tinyint unsigned AUTO_INCREMENT"
+			} else {
+				sqlType = "tinyint unsigned"
+			}
+		case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "int unsigned AUTO_INCREMENT"
+			} else {
+				sqlType = "int unsigned"
+			}
+		case reflect.Int64:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "bigint AUTO_INCREMENT"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Uint64:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "bigint unsigned AUTO_INCREMENT"
+			} else {
+				sqlType = "bigint unsigned"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "double"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "longtext"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				precision := ""
+				if p, ok := field.TagSettingsGet("PRECISION"); ok {
+					precision = fmt.Sprintf("(%s)", p)
+				}
+
+				if _, ok := field.TagSettings["NOT NULL"]; ok || field.IsPrimaryKey {
+					sqlType = fmt.Sprintf("DATETIME%v", precision)
+				} else {
+					sqlType = fmt.Sprintf("DATETIME%v NULL", precision)
+				}
+			}
+		default:
+			if IsByteArrayOrSlice(dataValue) {
+				if size > 0 && size < 65532 {
+					sqlType = fmt.Sprintf("varbinary(%d)", size)
+				} else {
+					sqlType = "longblob"
+				}
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) in field %s for mysql", dataValue.Type().Name(), dataValue.Kind().String(), field.Name))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s mysql) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v ON %v", indexName, s.Quote(tableName)))
+	return err
+}
+
+func (s mysql) ModifyColumn(tableName string, columnName string, typ string) error {
+	_, err := s.db.Exec(fmt.Sprintf("ALTER TABLE %v MODIFY COLUMN %v %v", tableName, columnName, typ))
+	return err
+}
+
+func (s mysql) LimitAndOffsetSQL(limit, offset interface{}) (sql string, err error) {
+	if limit != nil {
+		parsedLimit, err := s.parseInt(limit)
+		if err != nil {
+			return "", err
+		}
+		if parsedLimit >= 0 {
+			sql += fmt.Sprintf(" LIMIT %d", parsedLimit)
+
+			if offset != nil {
+				parsedOffset, err := s.parseInt(offset)
+				if err != nil {
+					return "", err
+				}
+				if parsedOffset >= 0 {
+					sql += fmt.Sprintf(" OFFSET %d", parsedOffset)
+				}
+			}
+		}
+	}
+	return
+}
+
+func (s mysql) HasForeignKey(tableName string, foreignKeyName string) bool {
+	var count int
+	currentDatabase, tableName := currentDatabaseAndTable(&s, tableName)
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS WHERE CONSTRAINT_SCHEMA=? AND TABLE_NAME=? AND CONSTRAINT_NAME=? AND CONSTRAINT_TYPE='FOREIGN KEY'", currentDatabase, tableName, foreignKeyName).Scan(&count)
+	return count > 0
+}
+
+func (s mysql) HasTable(tableName string) bool {
+	currentDatabase, tableName := currentDatabaseAndTable(&s, tableName)
+	var name string
+	// allow mysql database name with '-' character
+	if err := s.db.QueryRow(fmt.Sprintf("SHOW TABLES FROM `%s` WHERE `Tables_in_%s` = ?", currentDatabase, currentDatabase), tableName).Scan(&name); err != nil {
+		if err == sql.ErrNoRows {
+			return false
+		}
+		panic(err)
+	} else {
+		return true
+	}
+}
+
+func (s mysql) HasIndex(tableName string, indexName string) bool {
+	currentDatabase, tableName := currentDatabaseAndTable(&s, tableName)
+	if rows, err := s.db.Query(fmt.Sprintf("SHOW INDEXES FROM `%s` FROM `%s` WHERE Key_name = ?", tableName, currentDatabase), indexName); err != nil {
+		panic(err)
+	} else {
+		defer rows.Close()
+		return rows.Next()
+	}
+}
+
+func (s mysql) HasColumn(tableName string, columnName string) bool {
+	currentDatabase, tableName := currentDatabaseAndTable(&s, tableName)
+	if rows, err := s.db.Query(fmt.Sprintf("SHOW COLUMNS FROM `%s` FROM `%s` WHERE Field = ?", tableName, currentDatabase), columnName); err != nil {
+		panic(err)
+	} else {
+		defer rows.Close()
+		return rows.Next()
+	}
+}
+
+func (s mysql) CurrentDatabase() (name string) {
+	s.db.QueryRow("SELECT DATABASE()").Scan(&name)
+	return
+}
+
+func (mysql) SelectFromDummyTable() string {
+	return "FROM DUAL"
+}
+
+func (s mysql) BuildKeyName(kind, tableName string, fields ...string) string {
+	keyName := s.commonDialect.BuildKeyName(kind, tableName, fields...)
+	if utf8.RuneCountInString(keyName) <= 64 {
+		return keyName
+	}
+	h := sha1.New()
+	h.Write([]byte(keyName))
+	bs := h.Sum(nil)
+
+	// sha1 is 40 characters, keep first 24 characters of destination
+	destRunes := []rune(keyNameRegex.ReplaceAllString(fields[0], "_"))
+	if len(destRunes) > 24 {
+		destRunes = destRunes[:24]
+	}
+
+	return fmt.Sprintf("%s%x", string(destRunes), bs)
+}
+
+// NormalizeIndexAndColumn returns index name and column name for specify an index prefix length if needed
+func (mysql) NormalizeIndexAndColumn(indexName, columnName string) (string, string) {
+	submatch := mysqlIndexRegex.FindStringSubmatch(indexName)
+	if len(submatch) != 3 {
+		return indexName, columnName
+	}
+	indexName = submatch[1]
+	columnName = fmt.Sprintf("%s(%s)", columnName, submatch[2])
+	return indexName, columnName
+}
+
+func (mysql) DefaultValueStr() string {
+	return "VALUES()"
+}
@@ -0,0 +1,147 @@
+package gorm
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+)
+
+type postgres struct {
+	commonDialect
+}
+
+func init() {
+	RegisterDialect("postgres", &postgres{})
+	RegisterDialect("cloudsqlpostgres", &postgres{})
+}
+
+func (postgres) GetName() string {
+	return "postgres"
+}
+
+func (postgres) BindVar(i int) string {
+	return fmt.Sprintf("$%v", i)
+}
+
+func (s *postgres) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field, s)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "boolean"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uintptr:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "serial"
+			} else {
+				sqlType = "integer"
+			}
+		case reflect.Int64, reflect.Uint32, reflect.Uint64:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "bigserial"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "numeric"
+		case reflect.String:
+			if _, ok := field.TagSettingsGet("SIZE"); !ok {
+				size = 0 // if SIZE haven't been set, use `text` as the default type, as there are no performance different
+			}
+
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "text"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "timestamp with time zone"
+			}
+		case reflect.Map:
+			if dataValue.Type().Name() == "Hstore" {
+				sqlType = "hstore"
+			}
+		default:
+			if IsByteArrayOrSlice(dataValue) {
+				sqlType = "bytea"
+
+				if isUUID(dataValue) {
+					sqlType = "uuid"
+				}
+
+				if isJSON(dataValue) {
+					sqlType = "jsonb"
+				}
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for postgres", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s postgres) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM pg_indexes WHERE tablename = $1 AND indexname = $2 AND schemaname = CURRENT_SCHEMA()", tableName, indexName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasForeignKey(tableName string, foreignKeyName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(con.conname) FROM pg_constraint con WHERE $1::regclass::oid = con.conrelid AND con.conname = $2 AND con.contype='f'", tableName, foreignKeyName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = $1 AND table_type = 'BASE TABLE' AND table_schema = CURRENT_SCHEMA()", tableName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.columns WHERE table_name = $1 AND column_name = $2 AND table_schema = CURRENT_SCHEMA()", tableName, columnName).Scan(&count)
+	return count > 0
+}
+
+func (s postgres) CurrentDatabase() (name string) {
+	s.db.QueryRow("SELECT CURRENT_DATABASE()").Scan(&name)
+	return
+}
+
+func (s postgres) LastInsertIDOutputInterstitial(tableName, key string, columns []string) string {
+	return ""
+}
+
+func (s postgres) LastInsertIDReturningSuffix(tableName, key string) string {
+	return fmt.Sprintf("RETURNING %v.%v", tableName, key)
+}
+
+func (postgres) SupportLastInsertID() bool {
+	return false
+}
+
+func isUUID(value reflect.Value) bool {
+	if value.Kind() != reflect.Array || value.Type().Len() != 16 {
+		return false
+	}
+	typename := value.Type().Name()
+	lower := strings.ToLower(typename)
+	return "uuid" == lower || "guid" == lower
+}
+
+func isJSON(value reflect.Value) bool {
+	_, ok := value.Interface().(json.RawMessage)
+	return ok
+}
@@ -0,0 +1,107 @@
+package gorm
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"time"
+)
+
+type sqlite3 struct {
+	commonDialect
+}
+
+func init() {
+	RegisterDialect("sqlite3", &sqlite3{})
+}
+
+func (sqlite3) GetName() string {
+	return "sqlite3"
+}
+
+// Get Data Type for Sqlite Dialect
+func (s *sqlite3) DataTypeOf(field *StructField) string {
+	var dataValue, sqlType, size, additionalType = ParseFieldStructForDialect(field, s)
+
+	if sqlType == "" {
+		switch dataValue.Kind() {
+		case reflect.Bool:
+			sqlType = "bool"
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uintptr:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "integer primary key autoincrement"
+			} else {
+				sqlType = "integer"
+			}
+		case reflect.Int64, reflect.Uint64:
+			if s.fieldCanAutoIncrement(field) {
+				field.TagSettingsSet("AUTO_INCREMENT", "AUTO_INCREMENT")
+				sqlType = "integer primary key autoincrement"
+			} else {
+				sqlType = "bigint"
+			}
+		case reflect.Float32, reflect.Float64:
+			sqlType = "real"
+		case reflect.String:
+			if size > 0 && size < 65532 {
+				sqlType = fmt.Sprintf("varchar(%d)", size)
+			} else {
+				sqlType = "text"
+			}
+		case reflect.Struct:
+			if _, ok := dataValue.Interface().(time.Time); ok {
+				sqlType = "datetime"
+			}
+		default:
+			if IsByteArrayOrSlice(dataValue) {
+				sqlType = "blob"
+			}
+		}
+	}
+
+	if sqlType == "" {
+		panic(fmt.Sprintf("invalid sql type %s (%s) for sqlite3", dataValue.Type().Name(), dataValue.Kind().String()))
+	}
+
+	if strings.TrimSpace(additionalType) == "" {
+		return sqlType
+	}
+	return fmt.Sprintf("%v %v", sqlType, additionalType)
+}
+
+func (s sqlite3) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.db.QueryRow(fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND sql LIKE '%%INDEX %v ON%%'", indexName), tableName).Scan(&count)
+	return count > 0
+}
+
+func (s sqlite3) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM sqlite_master WHERE type='table' AND name=?", tableName).Scan(&count)
+	return count > 0
+}
+
+func (s sqlite3) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow(fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND (sql LIKE '%%\"%v\" %%' OR sql LIKE '%%%v %%');\n", columnName, columnName), tableName).Scan(&count)
+	return count > 0
+}
+
+func (s sqlite3) CurrentDatabase() (name string) {
+	var (
+		ifaces   = make([]interface{}, 3)
+		pointers = make([]*string, 3)
+		i        int
+	)
+	for i = 0; i < 3; i++ {
+		ifaces[i] = &pointers[i]
+	}
+	if err := s.db.QueryRow("PRAGMA database_list").Scan(ifaces...); err != nil {
+		return
+	}
+	if pointers[1] != nil {
+		name = *pointers[1]
+	}
+	return
+}
@@ -0,0 +1,81 @@
+package postgres
+
+import (
+	"database/sql"
+	"database/sql/driver"
+
+	"encoding/json"
+	"errors"
+	"fmt"
+
+	_ "github.com/lib/pq"
+	"github.com/lib/pq/hstore"
+)
+
+type Hstore map[string]*string
+
+// Value get value of Hstore
+func (h Hstore) Value() (driver.Value, error) {
+	hstore := hstore.Hstore{Map: map[string]sql.NullString{}}
+	if len(h) == 0 {
+		return nil, nil
+	}
+
+	for key, value := range h {
+		var s sql.NullString
+		if value != nil {
+			s.String = *value
+			s.Valid = true
+		}
+		hstore.Map[key] = s
+	}
+	return hstore.Value()
+}
+
+// Scan scan value into Hstore
+func (h *Hstore) Scan(value interface{}) error {
+	hstore := hstore.Hstore{}
+
+	if err := hstore.Scan(value); err != nil {
+		return err
+	}
+
+	if len(hstore.Map) == 0 {
+		return nil
+	}
+
+	*h = Hstore{}
+	for k := range hstore.Map {
+		if hstore.Map[k].Valid {
+			s := hstore.Map[k].String
+			(*h)[k] = &s
+		} else {
+			(*h)[k] = nil
+		}
+	}
+
+	return nil
+}
+
+// Jsonb Postgresql's JSONB data type
+type Jsonb struct {
+	json.RawMessage
+}
+
+// Value get value of Jsonb
+func (j Jsonb) Value() (driver.Value, error) {
+	if len(j.RawMessage) == 0 {
+		return nil, nil
+	}
+	return j.MarshalJSON()
+}
+
+// Scan scan value into Jsonb
+func (j *Jsonb) Scan(value interface{}) error {
+	bytes, ok := value.([]byte)
+	if !ok {
+		return errors.New(fmt.Sprint("Failed to unmarshal JSONB value:", value))
+	}
+
+	return json.Unmarshal(bytes, j)
+}
@@ -0,0 +1,30 @@
+version: '3'
+
+services:
+  mysql:
+    image: 'mysql:latest'
+    ports:
+      - 9910:3306
+    environment:
+      - MYSQL_DATABASE=gorm
+      - MYSQL_USER=gorm
+      - MYSQL_PASSWORD=gorm
+      - MYSQL_RANDOM_ROOT_PASSWORD="yes"
+  postgres:
+    image: 'postgres:latest'
+    ports:
+      - 9920:5432
+    environment:
+      - POSTGRES_USER=gorm
+      - POSTGRES_DB=gorm
+      - POSTGRES_PASSWORD=gorm
+  mssql:
+    image: 'mcmoe/mssqldocker:latest'
+    ports:
+      - 9930:1433
+    environment:
+      - ACCEPT_EULA=Y
+      - SA_PASSWORD=LoremIpsum86
+      - MSSQL_DB=gorm
+      - MSSQL_USER=gorm
+      - MSSQL_PASSWORD=LoremIpsum86
@@ -0,0 +1,72 @@
+package gorm
+
+import (
+	"errors"
+	"strings"
+)
+
+var (
+	// ErrRecordNotFound returns a "record not found error". Occurs only when attempting to query the database with a struct; querying with a slice won't return this error
+	ErrRecordNotFound = errors.New("record not found")
+	// ErrInvalidSQL occurs when you attempt a query with invalid SQL
+	ErrInvalidSQL = errors.New("invalid SQL")
+	// ErrInvalidTransaction occurs when you are trying to `Commit` or `Rollback`
+	ErrInvalidTransaction = errors.New("no valid transaction")
+	// ErrCantStartTransaction can't start transaction when you are trying to start one with `Begin`
+	ErrCantStartTransaction = errors.New("can't start transaction")
+	// ErrUnaddressable unaddressable value
+	ErrUnaddressable = errors.New("using unaddressable value")
+)
+
+// Errors contains all happened errors
+type Errors []error
+
+// IsRecordNotFoundError returns true if error contains a RecordNotFound error
+func IsRecordNotFoundError(err error) bool {
+	if errs, ok := err.(Errors); ok {
+		for _, err := range errs {
+			if err == ErrRecordNotFound {
+				return true
+			}
+		}
+	}
+	return err == ErrRecordNotFound
+}
+
+// GetErrors gets all errors that have occurred and returns a slice of errors (Error type)
+func (errs Errors) GetErrors() []error {
+	return errs
+}
+
+// Add adds an error to a given slice of errors
+func (errs Errors) Add(newErrors ...error) Errors {
+	for _, err := range newErrors {
+		if err == nil {
+			continue
+		}
+
+		if errors, ok := err.(Errors); ok {
+			errs = errs.Add(errors...)
+		} else {
+			ok = true
+			for _, e := range errs {
+				if err == e {
+					ok = false
+				}
+			}
+			if ok {
+				errs = append(errs, err)
+			}
+		}
+	}
+	return errs
+}
+
+// Error takes a slice of all errors that have occurred and returns it as a formatted string
+func (errs Errors) Error() string {
+	var errors = []string{}
+	for _, e := range errs {
+		errors = append(errors, e.Error())
+	}
+	return strings.Join(errors, "; ")
+}
@@ -0,0 +1,66 @@
+package gorm
+
+import (
+	"database/sql"
+	"database/sql/driver"
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+// Field model field definition
+type Field struct {
+	*StructField
+	IsBlank bool
+	Field   reflect.Value
+}
+
+// Set set a value to the field
+func (field *Field) Set(value interface{}) (err error) {
+	if !field.Field.IsValid() {
+		return errors.New("field value not valid")
+	}
+
+	if !field.Field.CanAddr() {
+		return ErrUnaddressable
+	}
+
+	reflectValue, ok := value.(reflect.Value)
+	if !ok {
+		reflectValue = reflect.ValueOf(value)
+	}
+
+	fieldValue := field.Field
+	if reflectValue.IsValid() {
+		if reflectValue.Type().ConvertibleTo(fieldValue.Type()) {
+			fieldValue.Set(reflectValue.Convert(fieldValue.Type()))
+		} else {
+			if fieldValue.Kind() == reflect.Ptr {
+				if fieldValue.IsNil() {
+					fieldValue.Set(reflect.New(field.Struct.Type.Elem()))
+				}
+				fieldValue = fieldValue.Elem()
+			}
+
+			if reflectValue.Type().ConvertibleTo(fieldValue.Type()) {
+				fieldValue.Set(reflectValue.Convert(fieldValue.Type()))
+			} else if scanner, ok := fieldValue.Addr().Interface().(sql.Scanner); ok {
+				v := reflectValue.Interface()
+				if valuer, ok := v.(driver.Valuer); ok {
+					if v, err = valuer.Value(); err == nil {
+						err = scanner.Scan(v)
+					}
+				} else {
+					err = scanner.Scan(v)
+				}
+			} else {
+				err = fmt.Errorf("could not convert argument of field %s from %s to %s", field.Name, reflectValue.Type(), fieldValue.Type())
+			}
+		}
+	} else {
+		field.Field.Set(reflect.Zero(field.Field.Type()))
+	}
+
+	field.IsBlank = isBlank(field.Field)
+	return err
+}
@@ -0,0 +1,14 @@
+module github.com/jinzhu/gorm
+
+go 1.12
+
+require (
+	github.com/denisenkom/go-mssqldb v0.0.0-20191124224453-732737034ffd
+	github.com/erikstmartin/go-testdb v0.0.0-20160219214506-8d10e4a1bae5
+	github.com/go-sql-driver/mysql v1.5.0
+	github.com/jinzhu/inflection v1.0.0
+	github.com/jinzhu/now v1.0.1
+	github.com/lib/pq v1.1.1
+	github.com/mattn/go-sqlite3 v2.0.1+incompatible
+	golang.org/x/crypto v0.0.0-20191205180655-e7c4368fe9dd // indirect
+)
@@ -0,0 +1,25 @@
+github.com/denisenkom/go-mssqldb v0.0.0-20191124224453-732737034ffd h1:83Wprp6ROGeiHFAP8WJdI2RoxALQYgdllERc3N5N2DM=
+github.com/denisenkom/go-mssqldb v0.0.0-20191124224453-732737034ffd/go.mod h1:xbL0rPBG9cCiLr28tMa8zpbdarY27NDyej4t/EjAShU=
+github.com/erikstmartin/go-testdb v0.0.0-20160219214506-8d10e4a1bae5 h1:Yzb9+7DPaBjB8zlTR87/ElzFsnQfuHnVUVqpZZIcV5Y=
+github.com/erikstmartin/go-testdb v0.0.0-20160219214506-8d10e4a1bae5/go.mod h1:a2zkGnVExMxdzMo3M0Hi/3sEU+cWnZpSni0O6/Yb/P0=
+github.com/go-sql-driver/mysql v1.5.0 h1:ozyZYNQW3x3HtqT1jira07DN2PArx2v7/mN66gGcHOs=
+github.com/go-sql-driver/mysql v1.5.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/golang-sql/civil v0.0.0-20190719163853-cb61b32ac6fe h1:lXe2qZdvpiX5WZkZR4hgp4KJVfY3nMkvmwbVkpv1rVY=
+github.com/golang-sql/civil v0.0.0-20190719163853-cb61b32ac6fe/go.mod h1:8vg3r2VgvsThLBIFL93Qb5yWzgyZWhEmBwUJWevAkK0=
+github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD/E=
+github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
+github.com/jinzhu/now v1.0.1 h1:HjfetcXq097iXP0uoPCdnM4Efp5/9MsM0/M+XOTeR3M=
+github.com/jinzhu/now v1.0.1/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
+github.com/lib/pq v1.1.1 h1:sJZmqHoEaY7f+NPP8pgLB/WxulyR3fewgCM2qaSlBb4=
+github.com/lib/pq v1.1.1/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
+github.com/mattn/go-sqlite3 v2.0.1+incompatible h1:xQ15muvnzGBHpIpdrNi1DA5x0+TcBZzsIDwmw9uTHzw=
+github.com/mattn/go-sqlite3 v2.0.1+incompatible/go.mod h1:FPy6KqzDD04eiIsT53CuJW3U88zkxoIYsOqkbpncsNc=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c h1:Vj5n4GlwjmQteupaxJ9+0FNOmBrHfq7vN4btdGoDZgI=
+golang.org/x/crypto v0.0.0-20190325154230-a5d413f7728c/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191205180655-e7c4368fe9dd h1:GGJVjV8waZKRHrgwvtH66z9ZGVurTD1MT0n1Bb+q4aM=
+golang.org/x/crypto v0.0.0-20191205180655-e7c4368fe9dd/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -0,0 +1,24 @@
+package gorm
+
+import (
+	"context"
+	"database/sql"
+)
+
+// SQLCommon is the minimal database connection functionality gorm requires.  Implemented by *sql.DB.
+type SQLCommon interface {
+	Exec(query string, args ...interface{}) (sql.Result, error)
+	Prepare(query string) (*sql.Stmt, error)
+	Query(query string, args ...interface{}) (*sql.Rows, error)
+	QueryRow(query string, args ...interface{}) *sql.Row
+}
+
+type sqlDb interface {
+	Begin() (*sql.Tx, error)
+	BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error)
+}
+
+type sqlTx interface {
+	Commit() error
+	Rollback() error
+}
@@ -0,0 +1,211 @@
+package gorm
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+// JoinTableHandlerInterface is an interface for how to handle many2many relations
+type JoinTableHandlerInterface interface {
+	// initialize join table handler
+	Setup(relationship *Relationship, tableName string, source reflect.Type, destination reflect.Type)
+	// Table return join table's table name
+	Table(db *DB) string
+	// Add create relationship in join table for source and destination
+	Add(handler JoinTableHandlerInterface, db *DB, source interface{}, destination interface{}) error
+	// Delete delete relationship in join table for sources
+	Delete(handler JoinTableHandlerInterface, db *DB, sources ...interface{}) error
+	// JoinWith query with `Join` conditions
+	JoinWith(handler JoinTableHandlerInterface, db *DB, source interface{}) *DB
+	// SourceForeignKeys return source foreign keys
+	SourceForeignKeys() []JoinTableForeignKey
+	// DestinationForeignKeys return destination foreign keys
+	DestinationForeignKeys() []JoinTableForeignKey
+}
+
+// JoinTableForeignKey join table foreign key struct
+type JoinTableForeignKey struct {
+	DBName            string
+	AssociationDBName string
+}
+
+// JoinTableSource is a struct that contains model type and foreign keys
+type JoinTableSource struct {
+	ModelType   reflect.Type
+	ForeignKeys []JoinTableForeignKey
+}
+
+// JoinTableHandler default join table handler
+type JoinTableHandler struct {
+	TableName   string          `sql:"-"`
+	Source      JoinTableSource `sql:"-"`
+	Destination JoinTableSource `sql:"-"`
+}
+
+// SourceForeignKeys return source foreign keys
+func (s *JoinTableHandler) SourceForeignKeys() []JoinTableForeignKey {
+	return s.Source.ForeignKeys
+}
+
+// DestinationForeignKeys return destination foreign keys
+func (s *JoinTableHandler) DestinationForeignKeys() []JoinTableForeignKey {
+	return s.Destination.ForeignKeys
+}
+
+// Setup initialize a default join table handler
+func (s *JoinTableHandler) Setup(relationship *Relationship, tableName string, source reflect.Type, destination reflect.Type) {
+	s.TableName = tableName
+
+	s.Source = JoinTableSource{ModelType: source}
+	s.Source.ForeignKeys = []JoinTableForeignKey{}
+	for idx, dbName := range relationship.ForeignFieldNames {
+		s.Source.ForeignKeys = append(s.Source.ForeignKeys, JoinTableForeignKey{
+			DBName:            relationship.ForeignDBNames[idx],
+			AssociationDBName: dbName,
+		})
+	}
+
+	s.Destination = JoinTableSource{ModelType: destination}
+	s.Destination.ForeignKeys = []JoinTableForeignKey{}
+	for idx, dbName := range relationship.AssociationForeignFieldNames {
+		s.Destination.ForeignKeys = append(s.Destination.ForeignKeys, JoinTableForeignKey{
+			DBName:            relationship.AssociationForeignDBNames[idx],
+			AssociationDBName: dbName,
+		})
+	}
+}
+
+// Table return join table's table name
+func (s JoinTableHandler) Table(db *DB) string {
+	return DefaultTableNameHandler(db, s.TableName)
+}
+
+func (s JoinTableHandler) updateConditionMap(conditionMap map[string]interface{}, db *DB, joinTableSources []JoinTableSource, sources ...interface{}) {
+	for _, source := range sources {
+		scope := db.NewScope(source)
+		modelType := scope.GetModelStruct().ModelType
+
+		for _, joinTableSource := range joinTableSources {
+			if joinTableSource.ModelType == modelType {
+				for _, foreignKey := range joinTableSource.ForeignKeys {
+					if field, ok := scope.FieldByName(foreignKey.AssociationDBName); ok {
+						conditionMap[foreignKey.DBName] = field.Field.Interface()
+					}
+				}
+				break
+			}
+		}
+	}
+}
+
+// Add create relationship in join table for source and destination
+func (s JoinTableHandler) Add(handler JoinTableHandlerInterface, db *DB, source interface{}, destination interface{}) error {
+	var (
+		scope        = db.NewScope("")
+		conditionMap = map[string]interface{}{}
+	)
+
+	// Update condition map for source
+	s.updateConditionMap(conditionMap, db, []JoinTableSource{s.Source}, source)
+
+	// Update condition map for destination
+	s.updateConditionMap(conditionMap, db, []JoinTableSource{s.Destination}, destination)
+
+	var assignColumns, binVars, conditions []string
+	var values []interface{}
+	for key, value := range conditionMap {
+		assignColumns = append(assignColumns, scope.Quote(key))
+		binVars = append(binVars, `?`)
+		conditions = append(conditions, fmt.Sprintf("%v = ?", scope.Quote(key)))
+		values = append(values, value)
+	}
+
+	for _, value := range values {
+		values = append(values, value)
+	}
+
+	quotedTable := scope.Quote(handler.Table(db))
+	sql := fmt.Sprintf(
+		"INSERT INTO %v (%v) SELECT %v %v WHERE NOT EXISTS (SELECT * FROM %v WHERE %v)",
+		quotedTable,
+		strings.Join(assignColumns, ","),
+		strings.Join(binVars, ","),
+		scope.Dialect().SelectFromDummyTable(),
+		quotedTable,
+		strings.Join(conditions, " AND "),
+	)
+
+	return db.Exec(sql, values...).Error
+}
+
+// Delete delete relationship in join table for sources
+func (s JoinTableHandler) Delete(handler JoinTableHandlerInterface, db *DB, sources ...interface{}) error {
+	var (
+		scope        = db.NewScope(nil)
+		conditions   []string
+		values       []interface{}
+		conditionMap = map[string]interface{}{}
+	)
+
+	s.updateConditionMap(conditionMap, db, []JoinTableSource{s.Source, s.Destination}, sources...)
+
+	for key, value := range conditionMap {
+		conditions = append(conditions, fmt.Sprintf("%v = ?", scope.Quote(key)))
+		values = append(values, value)
+	}
+
+	return db.Table(handler.Table(db)).Where(strings.Join(conditions, " AND "), values...).Delete("").Error
+}
+
+// JoinWith query with `Join` conditions
+func (s JoinTableHandler) JoinWith(handler JoinTableHandlerInterface, db *DB, source interface{}) *DB {
+	var (
+		scope           = db.NewScope(source)
+		tableName       = handler.Table(db)
+		quotedTableName = scope.Quote(tableName)
+		joinConditions  []string
+		values          []interface{}
+	)
+
+	if s.Source.ModelType == scope.GetModelStruct().ModelType {
+		destinationTableName := db.NewScope(reflect.New(s.Destination.ModelType).Interface()).QuotedTableName()
+		for _, foreignKey := range s.Destination.ForeignKeys {
+			joinConditions = append(joinConditions, fmt.Sprintf("%v.%v = %v.%v", quotedTableName, scope.Quote(foreignKey.DBName), destinationTableName, scope.Quote(foreignKey.AssociationDBName)))
+		}
+
+		var foreignDBNames []string
+		var foreignFieldNames []string
+
+		for _, foreignKey := range s.Source.ForeignKeys {
+			foreignDBNames = append(foreignDBNames, foreignKey.DBName)
+			if field, ok := scope.FieldByName(foreignKey.AssociationDBName); ok {
+				foreignFieldNames = append(foreignFieldNames, field.Name)
+			}
+		}
+
+		foreignFieldValues := scope.getColumnAsArray(foreignFieldNames, scope.Value)
+
+		var condString string
+		if len(foreignFieldValues) > 0 {
+			var quotedForeignDBNames []string
+			for _, dbName := range foreignDBNames {
+				quotedForeignDBNames = append(quotedForeignDBNames, tableName+"."+dbName)
+			}
+
+			condString = fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, quotedForeignDBNames), toQueryMarks(foreignFieldValues))
+
+			keys := scope.getColumnAsArray(foreignFieldNames, scope.Value)
+			values = append(values, toQueryValues(keys))
+		} else {
+			condString = fmt.Sprintf("1 <> 1")
+		}
+
+		return db.Joins(fmt.Sprintf("INNER JOIN %v ON %v", quotedTableName, strings.Join(joinConditions, " AND "))).
+			Where(condString, toQueryValues(foreignFieldValues)...)
+	}
+
+	db.Error = errors.New("wrong source type for join table handler")
+	return db
+}
@@ -0,0 +1,141 @@
+package gorm
+
+import (
+	"database/sql/driver"
+	"fmt"
+	"log"
+	"os"
+	"reflect"
+	"regexp"
+	"strconv"
+	"time"
+	"unicode"
+)
+
+var (
+	defaultLogger            = Logger{log.New(os.Stdout, "\r\n", 0)}
+	sqlRegexp                = regexp.MustCompile(`\?`)
+	numericPlaceHolderRegexp = regexp.MustCompile(`\$\d+`)
+)
+
+func isPrintable(s string) bool {
+	for _, r := range s {
+		if !unicode.IsPrint(r) {
+			return false
+		}
+	}
+	return true
+}
+
+var LogFormatter = func(values ...interface{}) (messages []interface{}) {
+	if len(values) > 1 {
+		var (
+			sql             string
+			formattedValues []string
+			level           = values[0]
+			currentTime     = "\n\033[33m[" + NowFunc().Format("2006-01-02 15:04:05") + "]\033[0m"
+			source          = fmt.Sprintf("\033[35m(%v)\033[0m", values[1])
+		)
+
+		messages = []interface{}{source, currentTime}
+
+		if len(values) == 2 {
+			//remove the line break
+			currentTime = currentTime[1:]
+			//remove the brackets
+			source = fmt.Sprintf("\033[35m%v\033[0m", values[1])
+
+			messages = []interface{}{currentTime, source}
+		}
+
+		if level == "sql" {
+			// duration
+			messages = append(messages, fmt.Sprintf(" \033[36;1m[%.2fms]\033[0m ", float64(values[2].(time.Duration).Nanoseconds()/1e4)/100.0))
+			// sql
+
+			for _, value := range values[4].([]interface{}) {
+				indirectValue := reflect.Indirect(reflect.ValueOf(value))
+				if indirectValue.IsValid() {
+					value = indirectValue.Interface()
+					if t, ok := value.(time.Time); ok {
+						if t.IsZero() {
+							formattedValues = append(formattedValues, fmt.Sprintf("'%v'", "0000-00-00 00:00:00"))
+						} else {
+							formattedValues = append(formattedValues, fmt.Sprintf("'%v'", t.Format("2006-01-02 15:04:05")))
+						}
+					} else if b, ok := value.([]byte); ok {
+						if str := string(b); isPrintable(str) {
+							formattedValues = append(formattedValues, fmt.Sprintf("'%v'", str))
+						} else {
+							formattedValues = append(formattedValues, "'<binary>'")
+						}
+					} else if r, ok := value.(driver.Valuer); ok {
+						if value, err := r.Value(); err == nil && value != nil {
+							formattedValues = append(formattedValues, fmt.Sprintf("'%v'", value))
+						} else {
+							formattedValues = append(formattedValues, "NULL")
+						}
+					} else {
+						switch value.(type) {
+						case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64, bool:
+							formattedValues = append(formattedValues, fmt.Sprintf("%v", value))
+						default:
+							formattedValues = append(formattedValues, fmt.Sprintf("'%v'", value))
+						}
+					}
+				} else {
+					formattedValues = append(formattedValues, "NULL")
+				}
+			}
+
+			// differentiate between $n placeholders or else treat like ?
+			if numericPlaceHolderRegexp.MatchString(values[3].(string)) {
+				sql = values[3].(string)
+				for index, value := range formattedValues {
+					placeholder := fmt.Sprintf(`\$%d([^\d]|$)`, index+1)
+					sql = regexp.MustCompile(placeholder).ReplaceAllString(sql, value+"$1")
+				}
+			} else {
+				formattedValuesLength := len(formattedValues)
+				for index, value := range sqlRegexp.Split(values[3].(string), -1) {
+					sql += value
+					if index < formattedValuesLength {
+						sql += formattedValues[index]
+					}
+				}
+			}
+
+			messages = append(messages, sql)
+			messages = append(messages, fmt.Sprintf(" \n\033[36;31m[%v]\033[0m ", strconv.FormatInt(values[5].(int64), 10)+" rows affected or returned "))
+		} else {
+			messages = append(messages, "\033[31;1m")
+			messages = append(messages, values[2:]...)
+			messages = append(messages, "\033[0m")
+		}
+	}
+
+	return
+}
+
+type logger interface {
+	Print(v ...interface{})
+}
+
+// LogWriter log writer interface
+type LogWriter interface {
+	Println(v ...interface{})
+}
+
+// Logger default logger
+type Logger struct {
+	LogWriter
+}
+
+// Print format & print log
+func (logger Logger) Print(values ...interface{}) {
+	logger.Println(LogFormatter(values...)...)
+}
+
+type nopLogger struct{}
+
+func (nopLogger) Print(values ...interface{}) {}
@@ -0,0 +1,881 @@
+package gorm
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+	"sync"
+	"time"
+)
+
+// DB contains information for current db connection
+type DB struct {
+	sync.RWMutex
+	Value        interface{}
+	Error        error
+	RowsAffected int64
+
+	// single db
+	db                SQLCommon
+	blockGlobalUpdate bool
+	logMode           logModeValue
+	logger            logger
+	search            *search
+	values            sync.Map
+
+	// global db
+	parent        *DB
+	callbacks     *Callback
+	dialect       Dialect
+	singularTable bool
+
+	// function to be used to override the creating of a new timestamp
+	nowFuncOverride func() time.Time
+}
+
+type logModeValue int
+
+const (
+	defaultLogMode logModeValue = iota
+	noLogMode
+	detailedLogMode
+)
+
+// Open initialize a new db connection, need to import driver first, e.g:
+//
+//     import _ "github.com/go-sql-driver/mysql"
+//     func main() {
+//       db, err := gorm.Open("mysql", "user:password@/dbname?charset=utf8&parseTime=True&loc=Local")
+//     }
+// GORM has wrapped some drivers, for easier to remember driver's import path, so you could import the mysql driver with
+//    import _ "github.com/jinzhu/gorm/dialects/mysql"
+//    // import _ "github.com/jinzhu/gorm/dialects/postgres"
+//    // import _ "github.com/jinzhu/gorm/dialects/sqlite"
+//    // import _ "github.com/jinzhu/gorm/dialects/mssql"
+func Open(dialect string, args ...interface{}) (db *DB, err error) {
+	if len(args) == 0 {
+		err = errors.New("invalid database source")
+		return nil, err
+	}
+	var source string
+	var dbSQL SQLCommon
+	var ownDbSQL bool
+
+	switch value := args[0].(type) {
+	case string:
+		var driver = dialect
+		if len(args) == 1 {
+			source = value
+		} else if len(args) >= 2 {
+			driver = value
+			source = args[1].(string)
+		}
+		dbSQL, err = sql.Open(driver, source)
+		ownDbSQL = true
+	case SQLCommon:
+		dbSQL = value
+		ownDbSQL = false
+	default:
+		return nil, fmt.Errorf("invalid database source: %v is not a valid type", value)
+	}
+
+	db = &DB{
+		db:        dbSQL,
+		logger:    defaultLogger,
+		callbacks: DefaultCallback,
+		dialect:   newDialect(dialect, dbSQL),
+	}
+	db.parent = db
+	if err != nil {
+		return
+	}
+	// Send a ping to make sure the database connection is alive.
+	if d, ok := dbSQL.(*sql.DB); ok {
+		if err = d.Ping(); err != nil && ownDbSQL {
+			d.Close()
+		}
+	}
+	return
+}
+
+// New clone a new db connection without search conditions
+func (s *DB) New() *DB {
+	clone := s.clone()
+	clone.search = nil
+	clone.Value = nil
+	return clone
+}
+
+type closer interface {
+	Close() error
+}
+
+// Close close current db connection.  If database connection is not an io.Closer, returns an error.
+func (s *DB) Close() error {
+	if db, ok := s.parent.db.(closer); ok {
+		return db.Close()
+	}
+	return errors.New("can't close current db")
+}
+
+// DB get `*sql.DB` from current connection
+// If the underlying database connection is not a *sql.DB, returns nil
+func (s *DB) DB() *sql.DB {
+	db, ok := s.db.(*sql.DB)
+	if !ok {
+		panic("can't support full GORM on currently status, maybe this is a TX instance.")
+	}
+	return db
+}
+
+// CommonDB return the underlying `*sql.DB` or `*sql.Tx` instance, mainly intended to allow coexistence with legacy non-GORM code.
+func (s *DB) CommonDB() SQLCommon {
+	return s.db
+}
+
+// Dialect get dialect
+func (s *DB) Dialect() Dialect {
+	return s.dialect
+}
+
+// Callback return `Callbacks` container, you could add/change/delete callbacks with it
+//     db.Callback().Create().Register("update_created_at", updateCreated)
+// Refer https://jinzhu.github.io/gorm/development.html#callbacks
+func (s *DB) Callback() *Callback {
+	s.parent.callbacks = s.parent.callbacks.clone(s.logger)
+	return s.parent.callbacks
+}
+
+// SetLogger replace default logger
+func (s *DB) SetLogger(log logger) {
+	s.logger = log
+}
+
+// LogMode set log mode, `true` for detailed logs, `false` for no log, default, will only print error logs
+func (s *DB) LogMode(enable bool) *DB {
+	if enable {
+		s.logMode = detailedLogMode
+	} else {
+		s.logMode = noLogMode
+	}
+	return s
+}
+
+// SetNowFuncOverride set the function to be used when creating a new timestamp
+func (s *DB) SetNowFuncOverride(nowFuncOverride func() time.Time) *DB {
+	s.nowFuncOverride = nowFuncOverride
+	return s
+}
+
+// Get a new timestamp, using the provided nowFuncOverride on the DB instance if set,
+// otherwise defaults to the global NowFunc()
+func (s *DB) nowFunc() time.Time {
+	if s.nowFuncOverride != nil {
+		return s.nowFuncOverride()
+	}
+
+	return NowFunc()
+}
+
+// BlockGlobalUpdate if true, generates an error on update/delete without where clause.
+// This is to prevent eventual error with empty objects updates/deletions
+func (s *DB) BlockGlobalUpdate(enable bool) *DB {
+	s.blockGlobalUpdate = enable
+	return s
+}
+
+// HasBlockGlobalUpdate return state of block
+func (s *DB) HasBlockGlobalUpdate() bool {
+	return s.blockGlobalUpdate
+}
+
+// SingularTable use singular table by default
+func (s *DB) SingularTable(enable bool) {
+	s.parent.Lock()
+	defer s.parent.Unlock()
+	s.parent.singularTable = enable
+}
+
+// NewScope create a scope for current operation
+func (s *DB) NewScope(value interface{}) *Scope {
+	dbClone := s.clone()
+	dbClone.Value = value
+	scope := &Scope{db: dbClone, Value: value}
+	if s.search != nil {
+		scope.Search = s.search.clone()
+	} else {
+		scope.Search = &search{}
+	}
+	return scope
+}
+
+// QueryExpr returns the query as SqlExpr object
+func (s *DB) QueryExpr() *SqlExpr {
+	scope := s.NewScope(s.Value)
+	scope.InstanceSet("skip_bindvar", true)
+	scope.prepareQuerySQL()
+
+	return Expr(scope.SQL, scope.SQLVars...)
+}
+
+// SubQuery returns the query as sub query
+func (s *DB) SubQuery() *SqlExpr {
+	scope := s.NewScope(s.Value)
+	scope.InstanceSet("skip_bindvar", true)
+	scope.prepareQuerySQL()
+
+	return Expr(fmt.Sprintf("(%v)", scope.SQL), scope.SQLVars...)
+}
+
+// Where return a new relation, filter records with given conditions, accepts `map`, `struct` or `string` as conditions, refer http://jinzhu.github.io/gorm/crud.html#query
+func (s *DB) Where(query interface{}, args ...interface{}) *DB {
+	return s.clone().search.Where(query, args...).db
+}
+
+// Or filter records that match before conditions or this one, similar to `Where`
+func (s *DB) Or(query interface{}, args ...interface{}) *DB {
+	return s.clone().search.Or(query, args...).db
+}
+
+// Not filter records that don't match current conditions, similar to `Where`
+func (s *DB) Not(query interface{}, args ...interface{}) *DB {
+	return s.clone().search.Not(query, args...).db
+}
+
+// Limit specify the number of records to be retrieved
+func (s *DB) Limit(limit interface{}) *DB {
+	return s.clone().search.Limit(limit).db
+}
+
+// Offset specify the number of records to skip before starting to return the records
+func (s *DB) Offset(offset interface{}) *DB {
+	return s.clone().search.Offset(offset).db
+}
+
+// Order specify order when retrieve records from database, set reorder to `true` to overwrite defined conditions
+//     db.Order("name DESC")
+//     db.Order("name DESC", true) // reorder
+//     db.Order(gorm.Expr("name = ? DESC", "first")) // sql expression
+func (s *DB) Order(value interface{}, reorder ...bool) *DB {
+	return s.clone().search.Order(value, reorder...).db
+}
+
+// Select specify fields that you want to retrieve from database when querying, by default, will select all fields;
+// When creating/updating, specify fields that you want to save to database
+func (s *DB) Select(query interface{}, args ...interface{}) *DB {
+	return s.clone().search.Select(query, args...).db
+}
+
+// Omit specify fields that you want to ignore when saving to database for creating, updating
+func (s *DB) Omit(columns ...string) *DB {
+	return s.clone().search.Omit(columns...).db
+}
+
+// Group specify the group method on the find
+func (s *DB) Group(query string) *DB {
+	return s.clone().search.Group(query).db
+}
+
+// Having specify HAVING conditions for GROUP BY
+func (s *DB) Having(query interface{}, values ...interface{}) *DB {
+	return s.clone().search.Having(query, values...).db
+}
+
+// Joins specify Joins conditions
+//     db.Joins("JOIN emails ON emails.user_id = users.id AND emails.email = ?", "jinzhu@example.org").Find(&user)
+func (s *DB) Joins(query string, args ...interface{}) *DB {
+	return s.clone().search.Joins(query, args...).db
+}
+
+// Scopes pass current database connection to arguments `func(*DB) *DB`, which could be used to add conditions dynamically
+//     func AmountGreaterThan1000(db *gorm.DB) *gorm.DB {
+//         return db.Where("amount > ?", 1000)
+//     }
+//
+//     func OrderStatus(status []string) func (db *gorm.DB) *gorm.DB {
+//         return func (db *gorm.DB) *gorm.DB {
+//             return db.Scopes(AmountGreaterThan1000).Where("status in (?)", status)
+//         }
+//     }
+//
+//     db.Scopes(AmountGreaterThan1000, OrderStatus([]string{"paid", "shipped"})).Find(&orders)
+// Refer https://jinzhu.github.io/gorm/crud.html#scopes
+func (s *DB) Scopes(funcs ...func(*DB) *DB) *DB {
+	for _, f := range funcs {
+		s = f(s)
+	}
+	return s
+}
+
+// Unscoped return all record including deleted record, refer Soft Delete https://jinzhu.github.io/gorm/crud.html#soft-delete
+func (s *DB) Unscoped() *DB {
+	return s.clone().search.unscoped().db
+}
+
+// Attrs initialize struct with argument if record not found with `FirstOrInit` https://jinzhu.github.io/gorm/crud.html#firstorinit or `FirstOrCreate` https://jinzhu.github.io/gorm/crud.html#firstorcreate
+func (s *DB) Attrs(attrs ...interface{}) *DB {
+	return s.clone().search.Attrs(attrs...).db
+}
+
+// Assign assign result with argument regardless it is found or not with `FirstOrInit` https://jinzhu.github.io/gorm/crud.html#firstorinit or `FirstOrCreate` https://jinzhu.github.io/gorm/crud.html#firstorcreate
+func (s *DB) Assign(attrs ...interface{}) *DB {
+	return s.clone().search.Assign(attrs...).db
+}
+
+// First find first record that match given conditions, order by primary key
+func (s *DB) First(out interface{}, where ...interface{}) *DB {
+	newScope := s.NewScope(out)
+	newScope.Search.Limit(1)
+
+	return newScope.Set("gorm:order_by_primary_key", "ASC").
+		inlineCondition(where...).callCallbacks(s.parent.callbacks.queries).db
+}
+
+// Take return a record that match given conditions, the order will depend on the database implementation
+func (s *DB) Take(out interface{}, where ...interface{}) *DB {
+	newScope := s.NewScope(out)
+	newScope.Search.Limit(1)
+	return newScope.inlineCondition(where...).callCallbacks(s.parent.callbacks.queries).db
+}
+
+// Last find last record that match given conditions, order by primary key
+func (s *DB) Last(out interface{}, where ...interface{}) *DB {
+	newScope := s.NewScope(out)
+	newScope.Search.Limit(1)
+	return newScope.Set("gorm:order_by_primary_key", "DESC").
+		inlineCondition(where...).callCallbacks(s.parent.callbacks.queries).db
+}
+
+// Find find records that match given conditions
+func (s *DB) Find(out interface{}, where ...interface{}) *DB {
+	return s.NewScope(out).inlineCondition(where...).callCallbacks(s.parent.callbacks.queries).db
+}
+
+//Preloads preloads relations, don`t touch out
+func (s *DB) Preloads(out interface{}) *DB {
+	return s.NewScope(out).InstanceSet("gorm:only_preload", 1).callCallbacks(s.parent.callbacks.queries).db
+}
+
+// Scan scan value to a struct
+func (s *DB) Scan(dest interface{}) *DB {
+	return s.NewScope(s.Value).Set("gorm:query_destination", dest).callCallbacks(s.parent.callbacks.queries).db
+}
+
+// Row return `*sql.Row` with given conditions
+func (s *DB) Row() *sql.Row {
+	return s.NewScope(s.Value).row()
+}
+
+// Rows return `*sql.Rows` with given conditions
+func (s *DB) Rows() (*sql.Rows, error) {
+	return s.NewScope(s.Value).rows()
+}
+
+// ScanRows scan `*sql.Rows` to give struct
+func (s *DB) ScanRows(rows *sql.Rows, result interface{}) error {
+	var (
+		scope        = s.NewScope(result)
+		clone        = scope.db
+		columns, err = rows.Columns()
+	)
+
+	if clone.AddError(err) == nil {
+		scope.scan(rows, columns, scope.Fields())
+	}
+
+	return clone.Error
+}
+
+// Pluck used to query single column from a model as a map
+//     var ages []int64
+//     db.Find(&users).Pluck("age", &ages)
+func (s *DB) Pluck(column string, value interface{}) *DB {
+	return s.NewScope(s.Value).pluck(column, value).db
+}
+
+// Count get how many records for a model
+func (s *DB) Count(value interface{}) *DB {
+	return s.NewScope(s.Value).count(value).db
+}
+
+// Related get related associations
+func (s *DB) Related(value interface{}, foreignKeys ...string) *DB {
+	return s.NewScope(s.Value).related(value, foreignKeys...).db
+}
+
+// FirstOrInit find first matched record or initialize a new one with given conditions (only works with struct, map conditions)
+// https://jinzhu.github.io/gorm/crud.html#firstorinit
+func (s *DB) FirstOrInit(out interface{}, where ...interface{}) *DB {
+	c := s.clone()
+	if result := c.First(out, where...); result.Error != nil {
+		if !result.RecordNotFound() {
+			return result
+		}
+		c.NewScope(out).inlineCondition(where...).initialize()
+	} else {
+		c.NewScope(out).updatedAttrsWithValues(c.search.assignAttrs)
+	}
+	return c
+}
+
+// FirstOrCreate find first matched record or create a new one with given conditions (only works with struct, map conditions)
+// https://jinzhu.github.io/gorm/crud.html#firstorcreate
+func (s *DB) FirstOrCreate(out interface{}, where ...interface{}) *DB {
+	c := s.clone()
+	if result := s.First(out, where...); result.Error != nil {
+		if !result.RecordNotFound() {
+			return result
+		}
+		return c.NewScope(out).inlineCondition(where...).initialize().callCallbacks(c.parent.callbacks.creates).db
+	} else if len(c.search.assignAttrs) > 0 {
+		return c.NewScope(out).InstanceSet("gorm:update_interface", c.search.assignAttrs).callCallbacks(c.parent.callbacks.updates).db
+	}
+	return c
+}
+
+// Update update attributes with callbacks, refer: https://jinzhu.github.io/gorm/crud.html#update
+// WARNING when update with struct, GORM will not update fields that with zero value
+func (s *DB) Update(attrs ...interface{}) *DB {
+	return s.Updates(toSearchableMap(attrs...), true)
+}
+
+// Updates update attributes with callbacks, refer: https://jinzhu.github.io/gorm/crud.html#update
+func (s *DB) Updates(values interface{}, ignoreProtectedAttrs ...bool) *DB {
+	return s.NewScope(s.Value).
+		Set("gorm:ignore_protected_attrs", len(ignoreProtectedAttrs) > 0).
+		InstanceSet("gorm:update_interface", values).
+		callCallbacks(s.parent.callbacks.updates).db
+}
+
+// UpdateColumn update attributes without callbacks, refer: https://jinzhu.github.io/gorm/crud.html#update
+func (s *DB) UpdateColumn(attrs ...interface{}) *DB {
+	return s.UpdateColumns(toSearchableMap(attrs...))
+}
+
+// UpdateColumns update attributes without callbacks, refer: https://jinzhu.github.io/gorm/crud.html#update
+func (s *DB) UpdateColumns(values interface{}) *DB {
+	return s.NewScope(s.Value).
+		Set("gorm:update_column", true).
+		Set("gorm:save_associations", false).
+		InstanceSet("gorm:update_interface", values).
+		callCallbacks(s.parent.callbacks.updates).db
+}
+
+// Save update value in database, if the value doesn't have primary key, will insert it
+func (s *DB) Save(value interface{}) *DB {
+	scope := s.NewScope(value)
+	if !scope.PrimaryKeyZero() {
+		newDB := scope.callCallbacks(s.parent.callbacks.updates).db
+		if newDB.Error == nil && newDB.RowsAffected == 0 {
+			return s.New().Table(scope.TableName()).FirstOrCreate(value)
+		}
+		return newDB
+	}
+	return scope.callCallbacks(s.parent.callbacks.creates).db
+}
+
+// Create insert the value into database
+func (s *DB) Create(value interface{}) *DB {
+	scope := s.NewScope(value)
+	return scope.callCallbacks(s.parent.callbacks.creates).db
+}
+
+// Delete delete value match given conditions, if the value has primary key, then will including the primary key as condition
+// WARNING If model has DeletedAt field, GORM will only set field DeletedAt's value to current time
+func (s *DB) Delete(value interface{}, where ...interface{}) *DB {
+	return s.NewScope(value).inlineCondition(where...).callCallbacks(s.parent.callbacks.deletes).db
+}
+
+// Raw use raw sql as conditions, won't run it unless invoked by other methods
+//    db.Raw("SELECT name, age FROM users WHERE name = ?", 3).Scan(&result)
+func (s *DB) Raw(sql string, values ...interface{}) *DB {
+	return s.clone().search.Raw(true).Where(sql, values...).db
+}
+
+// Exec execute raw sql
+func (s *DB) Exec(sql string, values ...interface{}) *DB {
+	scope := s.NewScope(nil)
+	generatedSQL := scope.buildCondition(map[string]interface{}{"query": sql, "args": values}, true)
+	generatedSQL = strings.TrimSuffix(strings.TrimPrefix(generatedSQL, "("), ")")
+	scope.Raw(generatedSQL)
+	return scope.Exec().db
+}
+
+// Model specify the model you would like to run db operations
+//    // update all users's name to `hello`
+//    db.Model(&User{}).Update("name", "hello")
+//    // if user's primary key is non-blank, will use it as condition, then will only update the user's name to `hello`
+//    db.Model(&user).Update("name", "hello")
+func (s *DB) Model(value interface{}) *DB {
+	c := s.clone()
+	c.Value = value
+	return c
+}
+
+// Table specify the table you would like to run db operations
+func (s *DB) Table(name string) *DB {
+	clone := s.clone()
+	clone.search.Table(name)
+	clone.Value = nil
+	return clone
+}
+
+// Debug start debug mode
+func (s *DB) Debug() *DB {
+	return s.clone().LogMode(true)
+}
+
+// Transaction start a transaction as a block,
+// return error will rollback, otherwise to commit.
+func (s *DB) Transaction(fc func(tx *DB) error) (err error) {
+	panicked := true
+	tx := s.Begin()
+	defer func() {
+		// Make sure to rollback when panic, Block error or Commit error
+		if panicked || err != nil {
+			tx.Rollback()
+		}
+	}()
+
+	err = fc(tx)
+
+	if err == nil {
+		err = tx.Commit().Error
+	}
+
+	panicked = false
+	return
+}
+
+// Begin begins a transaction
+func (s *DB) Begin() *DB {
+	return s.BeginTx(context.Background(), &sql.TxOptions{})
+}
+
+// BeginTx begins a transaction with options
+func (s *DB) BeginTx(ctx context.Context, opts *sql.TxOptions) *DB {
+	c := s.clone()
+	if db, ok := c.db.(sqlDb); ok && db != nil {
+		tx, err := db.BeginTx(ctx, opts)
+		c.db = interface{}(tx).(SQLCommon)
+
+		c.dialect.SetDB(c.db)
+		c.AddError(err)
+	} else {
+		c.AddError(ErrCantStartTransaction)
+	}
+	return c
+}
+
+// Commit commit a transaction
+func (s *DB) Commit() *DB {
+	var emptySQLTx *sql.Tx
+	if db, ok := s.db.(sqlTx); ok && db != nil && db != emptySQLTx {
+		s.AddError(db.Commit())
+	} else {
+		s.AddError(ErrInvalidTransaction)
+	}
+	return s
+}
+
+// Rollback rollback a transaction
+func (s *DB) Rollback() *DB {
+	var emptySQLTx *sql.Tx
+	if db, ok := s.db.(sqlTx); ok && db != nil && db != emptySQLTx {
+		if err := db.Rollback(); err != nil && err != sql.ErrTxDone {
+			s.AddError(err)
+		}
+	} else {
+		s.AddError(ErrInvalidTransaction)
+	}
+	return s
+}
+
+// RollbackUnlessCommitted rollback a transaction if it has not yet been
+// committed.
+func (s *DB) RollbackUnlessCommitted() *DB {
+	var emptySQLTx *sql.Tx
+	if db, ok := s.db.(sqlTx); ok && db != nil && db != emptySQLTx {
+		err := db.Rollback()
+		// Ignore the error indicating that the transaction has already
+		// been committed.
+		if err != sql.ErrTxDone {
+			s.AddError(err)
+		}
+	} else {
+		s.AddError(ErrInvalidTransaction)
+	}
+	return s
+}
+
+// NewRecord check if value's primary key is blank
+func (s *DB) NewRecord(value interface{}) bool {
+	return s.NewScope(value).PrimaryKeyZero()
+}
+
+// RecordNotFound check if returning ErrRecordNotFound error
+func (s *DB) RecordNotFound() bool {
+	for _, err := range s.GetErrors() {
+		if err == ErrRecordNotFound {
+			return true
+		}
+	}
+	return false
+}
+
+// CreateTable create table for models
+func (s *DB) CreateTable(models ...interface{}) *DB {
+	db := s.Unscoped()
+	for _, model := range models {
+		db = db.NewScope(model).createTable().db
+	}
+	return db
+}
+
+// DropTable drop table for models
+func (s *DB) DropTable(values ...interface{}) *DB {
+	db := s.clone()
+	for _, value := range values {
+		if tableName, ok := value.(string); ok {
+			db = db.Table(tableName)
+		}
+
+		db = db.NewScope(value).dropTable().db
+	}
+	return db
+}
+
+// DropTableIfExists drop table if it is exist
+func (s *DB) DropTableIfExists(values ...interface{}) *DB {
+	db := s.clone()
+	for _, value := range values {
+		if s.HasTable(value) {
+			db.AddError(s.DropTable(value).Error)
+		}
+	}
+	return db
+}
+
+// HasTable check has table or not
+func (s *DB) HasTable(value interface{}) bool {
+	var (
+		scope     = s.NewScope(value)
+		tableName string
+	)
+
+	if name, ok := value.(string); ok {
+		tableName = name
+	} else {
+		tableName = scope.TableName()
+	}
+
+	has := scope.Dialect().HasTable(tableName)
+	s.AddError(scope.db.Error)
+	return has
+}
+
+// AutoMigrate run auto migration for given models, will only add missing fields, won't delete/change current data
+func (s *DB) AutoMigrate(values ...interface{}) *DB {
+	db := s.Unscoped()
+	for _, value := range values {
+		db = db.NewScope(value).autoMigrate().db
+	}
+	return db
+}
+
+// ModifyColumn modify column to type
+func (s *DB) ModifyColumn(column string, typ string) *DB {
+	scope := s.NewScope(s.Value)
+	scope.modifyColumn(column, typ)
+	return scope.db
+}
+
+// DropColumn drop a column
+func (s *DB) DropColumn(column string) *DB {
+	scope := s.NewScope(s.Value)
+	scope.dropColumn(column)
+	return scope.db
+}
+
+// AddIndex add index for columns with given name
+func (s *DB) AddIndex(indexName string, columns ...string) *DB {
+	scope := s.Unscoped().NewScope(s.Value)
+	scope.addIndex(false, indexName, columns...)
+	return scope.db
+}
+
+// AddUniqueIndex add unique index for columns with given name
+func (s *DB) AddUniqueIndex(indexName string, columns ...string) *DB {
+	scope := s.Unscoped().NewScope(s.Value)
+	scope.addIndex(true, indexName, columns...)
+	return scope.db
+}
+
+// RemoveIndex remove index with name
+func (s *DB) RemoveIndex(indexName string) *DB {
+	scope := s.NewScope(s.Value)
+	scope.removeIndex(indexName)
+	return scope.db
+}
+
+// AddForeignKey Add foreign key to the given scope, e.g:
+//     db.Model(&User{}).AddForeignKey("city_id", "cities(id)", "RESTRICT", "RESTRICT")
+func (s *DB) AddForeignKey(field string, dest string, onDelete string, onUpdate string) *DB {
+	scope := s.NewScope(s.Value)
+	scope.addForeignKey(field, dest, onDelete, onUpdate)
+	return scope.db
+}
+
+// RemoveForeignKey Remove foreign key from the given scope, e.g:
+//     db.Model(&User{}).RemoveForeignKey("city_id", "cities(id)")
+func (s *DB) RemoveForeignKey(field string, dest string) *DB {
+	scope := s.clone().NewScope(s.Value)
+	scope.removeForeignKey(field, dest)
+	return scope.db
+}
+
+// Association start `Association Mode` to handler relations things easir in that mode, refer: https://jinzhu.github.io/gorm/associations.html#association-mode
+func (s *DB) Association(column string) *Association {
+	var err error
+	var scope = s.Set("gorm:association:source", s.Value).NewScope(s.Value)
+
+	if primaryField := scope.PrimaryField(); primaryField.IsBlank {
+		err = errors.New("primary key can't be nil")
+	} else {
+		if field, ok := scope.FieldByName(column); ok {
+			if field.Relationship == nil || len(field.Relationship.ForeignFieldNames) == 0 {
+				err = fmt.Errorf("invalid association %v for %v", column, scope.IndirectValue().Type())
+			} else {
+				return &Association{scope: scope, column: column, field: field}
+			}
+		} else {
+			err = fmt.Errorf("%v doesn't have column %v", scope.IndirectValue().Type(), column)
+		}
+	}
+
+	return &Association{Error: err}
+}
+
+// Preload preload associations with given conditions
+//    db.Preload("Orders", "state NOT IN (?)", "cancelled").Find(&users)
+func (s *DB) Preload(column string, conditions ...interface{}) *DB {
+	return s.clone().search.Preload(column, conditions...).db
+}
+
+// Set set setting by name, which could be used in callbacks, will clone a new db, and update its setting
+func (s *DB) Set(name string, value interface{}) *DB {
+	return s.clone().InstantSet(name, value)
+}
+
+// InstantSet instant set setting, will affect current db
+func (s *DB) InstantSet(name string, value interface{}) *DB {
+	s.values.Store(name, value)
+	return s
+}
+
+// Get get setting by name
+func (s *DB) Get(name string) (value interface{}, ok bool) {
+	value, ok = s.values.Load(name)
+	return
+}
+
+// SetJoinTableHandler set a model's join table handler for a relation
+func (s *DB) SetJoinTableHandler(source interface{}, column string, handler JoinTableHandlerInterface) {
+	scope := s.NewScope(source)
+	for _, field := range scope.GetModelStruct().StructFields {
+		if field.Name == column || field.DBName == column {
+			if many2many, _ := field.TagSettingsGet("MANY2MANY"); many2many != "" {
+				source := (&Scope{Value: source}).GetModelStruct().ModelType
+				destination := (&Scope{Value: reflect.New(field.Struct.Type).Interface()}).GetModelStruct().ModelType
+				handler.Setup(field.Relationship, many2many, source, destination)
+				field.Relationship.JoinTableHandler = handler
+				if table := handler.Table(s); scope.Dialect().HasTable(table) {
+					s.Table(table).AutoMigrate(handler)
+				}
+			}
+		}
+	}
+}
+
+// AddError add error to the db
+func (s *DB) AddError(err error) error {
+	if err != nil {
+		if err != ErrRecordNotFound {
+			if s.logMode == defaultLogMode {
+				go s.print("error", fileWithLineNum(), err)
+			} else {
+				s.log(err)
+			}
+
+			errors := Errors(s.GetErrors())
+			errors = errors.Add(err)
+			if len(errors) > 1 {
+				err = errors
+			}
+		}
+
+		s.Error = err
+	}
+	return err
+}
+
+// GetErrors get happened errors from the db
+func (s *DB) GetErrors() []error {
+	if errs, ok := s.Error.(Errors); ok {
+		return errs
+	} else if s.Error != nil {
+		return []error{s.Error}
+	}
+	return []error{}
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Private Methods For DB
+////////////////////////////////////////////////////////////////////////////////
+
+func (s *DB) clone() *DB {
+	db := &DB{
+		db:                s.db,
+		parent:            s.parent,
+		logger:            s.logger,
+		logMode:           s.logMode,
+		Value:             s.Value,
+		Error:             s.Error,
+		blockGlobalUpdate: s.blockGlobalUpdate,
+		dialect:           newDialect(s.dialect.GetName(), s.db),
+		nowFuncOverride:   s.nowFuncOverride,
+	}
+
+	s.values.Range(func(k, v interface{}) bool {
+		db.values.Store(k, v)
+		return true
+	})
+
+	if s.search == nil {
+		db.search = &search{limit: -1, offset: -1}
+	} else {
+		db.search = s.search.clone()
+	}
+
+	db.search.db = db
+	return db
+}
+
+func (s *DB) print(v ...interface{}) {
+	s.logger.Print(v...)
+}
+
+func (s *DB) log(v ...interface{}) {
+	if s != nil && s.logMode == detailedLogMode {
+		s.print(append([]interface{}{"log", fileWithLineNum()}, v...)...)
+	}
+}
+
+func (s *DB) slog(sql string, t time.Time, vars ...interface{}) {
+	if s.logMode == detailedLogMode {
+		s.print("sql", fileWithLineNum(), NowFunc().Sub(t), sql, vars, s.RowsAffected)
+	}
+}
@@ -0,0 +1,14 @@
+package gorm
+
+import "time"
+
+// Model base model definition, including fields `ID`, `CreatedAt`, `UpdatedAt`, `DeletedAt`, which could be embedded in your models
+//    type User struct {
+//      gorm.Model
+//    }
+type Model struct {
+	ID        uint `gorm:"primary_key"`
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	DeletedAt *time.Time `sql:"index"`
+}
@@ -0,0 +1,671 @@
+package gorm
+
+import (
+	"database/sql"
+	"errors"
+	"go/ast"
+	"reflect"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/jinzhu/inflection"
+)
+
+// DefaultTableNameHandler default table name handler
+var DefaultTableNameHandler = func(db *DB, defaultTableName string) string {
+	return defaultTableName
+}
+
+// lock for mutating global cached model metadata
+var structsLock sync.Mutex
+
+// global cache of model metadata
+var modelStructsMap sync.Map
+
+// ModelStruct model definition
+type ModelStruct struct {
+	PrimaryFields []*StructField
+	StructFields  []*StructField
+	ModelType     reflect.Type
+
+	defaultTableName string
+	l                sync.Mutex
+}
+
+// TableName returns model's table name
+func (s *ModelStruct) TableName(db *DB) string {
+	s.l.Lock()
+	defer s.l.Unlock()
+
+	if s.defaultTableName == "" && db != nil && s.ModelType != nil {
+		// Set default table name
+		if tabler, ok := reflect.New(s.ModelType).Interface().(tabler); ok {
+			s.defaultTableName = tabler.TableName()
+		} else {
+			tableName := ToTableName(s.ModelType.Name())
+			db.parent.RLock()
+			if db == nil || (db.parent != nil && !db.parent.singularTable) {
+				tableName = inflection.Plural(tableName)
+			}
+			db.parent.RUnlock()
+			s.defaultTableName = tableName
+		}
+	}
+
+	return DefaultTableNameHandler(db, s.defaultTableName)
+}
+
+// StructField model field's struct definition
+type StructField struct {
+	DBName          string
+	Name            string
+	Names           []string
+	IsPrimaryKey    bool
+	IsNormal        bool
+	IsIgnored       bool
+	IsScanner       bool
+	HasDefaultValue bool
+	Tag             reflect.StructTag
+	TagSettings     map[string]string
+	Struct          reflect.StructField
+	IsForeignKey    bool
+	Relationship    *Relationship
+
+	tagSettingsLock sync.RWMutex
+}
+
+// TagSettingsSet Sets a tag in the tag settings map
+func (sf *StructField) TagSettingsSet(key, val string) {
+	sf.tagSettingsLock.Lock()
+	defer sf.tagSettingsLock.Unlock()
+	sf.TagSettings[key] = val
+}
+
+// TagSettingsGet returns a tag from the tag settings
+func (sf *StructField) TagSettingsGet(key string) (string, bool) {
+	sf.tagSettingsLock.RLock()
+	defer sf.tagSettingsLock.RUnlock()
+	val, ok := sf.TagSettings[key]
+	return val, ok
+}
+
+// TagSettingsDelete deletes a tag
+func (sf *StructField) TagSettingsDelete(key string) {
+	sf.tagSettingsLock.Lock()
+	defer sf.tagSettingsLock.Unlock()
+	delete(sf.TagSettings, key)
+}
+
+func (sf *StructField) clone() *StructField {
+	clone := &StructField{
+		DBName:          sf.DBName,
+		Name:            sf.Name,
+		Names:           sf.Names,
+		IsPrimaryKey:    sf.IsPrimaryKey,
+		IsNormal:        sf.IsNormal,
+		IsIgnored:       sf.IsIgnored,
+		IsScanner:       sf.IsScanner,
+		HasDefaultValue: sf.HasDefaultValue,
+		Tag:             sf.Tag,
+		TagSettings:     map[string]string{},
+		Struct:          sf.Struct,
+		IsForeignKey:    sf.IsForeignKey,
+	}
+
+	if sf.Relationship != nil {
+		relationship := *sf.Relationship
+		clone.Relationship = &relationship
+	}
+
+	// copy the struct field tagSettings, they should be read-locked while they are copied
+	sf.tagSettingsLock.Lock()
+	defer sf.tagSettingsLock.Unlock()
+	for key, value := range sf.TagSettings {
+		clone.TagSettings[key] = value
+	}
+
+	return clone
+}
+
+// Relationship described the relationship between models
+type Relationship struct {
+	Kind                         string
+	PolymorphicType              string
+	PolymorphicDBName            string
+	PolymorphicValue             string
+	ForeignFieldNames            []string
+	ForeignDBNames               []string
+	AssociationForeignFieldNames []string
+	AssociationForeignDBNames    []string
+	JoinTableHandler             JoinTableHandlerInterface
+}
+
+func getForeignField(column string, fields []*StructField) *StructField {
+	for _, field := range fields {
+		if field.Name == column || field.DBName == column || field.DBName == ToColumnName(column) {
+			return field
+		}
+	}
+	return nil
+}
+
+// GetModelStruct get value's model struct, relationships based on struct and tag definition
+func (scope *Scope) GetModelStruct() *ModelStruct {
+	var modelStruct ModelStruct
+	// Scope value can't be nil
+	if scope.Value == nil {
+		return &modelStruct
+	}
+
+	reflectType := reflect.ValueOf(scope.Value).Type()
+	for reflectType.Kind() == reflect.Slice || reflectType.Kind() == reflect.Ptr {
+		reflectType = reflectType.Elem()
+	}
+
+	// Scope value need to be a struct
+	if reflectType.Kind() != reflect.Struct {
+		return &modelStruct
+	}
+
+	// Get Cached model struct
+	isSingularTable := false
+	if scope.db != nil && scope.db.parent != nil {
+		scope.db.parent.RLock()
+		isSingularTable = scope.db.parent.singularTable
+		scope.db.parent.RUnlock()
+	}
+
+	hashKey := struct {
+		singularTable bool
+		reflectType   reflect.Type
+	}{isSingularTable, reflectType}
+	if value, ok := modelStructsMap.Load(hashKey); ok && value != nil {
+		return value.(*ModelStruct)
+	}
+
+	modelStruct.ModelType = reflectType
+
+	// Get all fields
+	for i := 0; i < reflectType.NumField(); i++ {
+		if fieldStruct := reflectType.Field(i); ast.IsExported(fieldStruct.Name) {
+			field := &StructField{
+				Struct:      fieldStruct,
+				Name:        fieldStruct.Name,
+				Names:       []string{fieldStruct.Name},
+				Tag:         fieldStruct.Tag,
+				TagSettings: parseTagSetting(fieldStruct.Tag),
+			}
+
+			// is ignored field
+			if _, ok := field.TagSettingsGet("-"); ok {
+				field.IsIgnored = true
+			} else {
+				if _, ok := field.TagSettingsGet("PRIMARY_KEY"); ok {
+					field.IsPrimaryKey = true
+					modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, field)
+				}
+
+				if _, ok := field.TagSettingsGet("DEFAULT"); ok && !field.IsPrimaryKey {
+					field.HasDefaultValue = true
+				}
+
+				if _, ok := field.TagSettingsGet("AUTO_INCREMENT"); ok && !field.IsPrimaryKey {
+					field.HasDefaultValue = true
+				}
+
+				indirectType := fieldStruct.Type
+				for indirectType.Kind() == reflect.Ptr {
+					indirectType = indirectType.Elem()
+				}
+
+				fieldValue := reflect.New(indirectType).Interface()
+				if _, isScanner := fieldValue.(sql.Scanner); isScanner {
+					// is scanner
+					field.IsScanner, field.IsNormal = true, true
+					if indirectType.Kind() == reflect.Struct {
+						for i := 0; i < indirectType.NumField(); i++ {
+							for key, value := range parseTagSetting(indirectType.Field(i).Tag) {
+								if _, ok := field.TagSettingsGet(key); !ok {
+									field.TagSettingsSet(key, value)
+								}
+							}
+						}
+					}
+				} else if _, isTime := fieldValue.(*time.Time); isTime {
+					// is time
+					field.IsNormal = true
+				} else if _, ok := field.TagSettingsGet("EMBEDDED"); ok || fieldStruct.Anonymous {
+					// is embedded struct
+					for _, subField := range scope.New(fieldValue).GetModelStruct().StructFields {
+						subField = subField.clone()
+						subField.Names = append([]string{fieldStruct.Name}, subField.Names...)
+						if prefix, ok := field.TagSettingsGet("EMBEDDED_PREFIX"); ok {
+							subField.DBName = prefix + subField.DBName
+						}
+
+						if subField.IsPrimaryKey {
+							if _, ok := subField.TagSettingsGet("PRIMARY_KEY"); ok {
+								modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, subField)
+							} else {
+								subField.IsPrimaryKey = false
+							}
+						}
+
+						if subField.Relationship != nil && subField.Relationship.JoinTableHandler != nil {
+							if joinTableHandler, ok := subField.Relationship.JoinTableHandler.(*JoinTableHandler); ok {
+								newJoinTableHandler := &JoinTableHandler{}
+								newJoinTableHandler.Setup(subField.Relationship, joinTableHandler.TableName, reflectType, joinTableHandler.Destination.ModelType)
+								subField.Relationship.JoinTableHandler = newJoinTableHandler
+							}
+						}
+
+						modelStruct.StructFields = append(modelStruct.StructFields, subField)
+					}
+					continue
+				} else {
+					// build relationships
+					switch indirectType.Kind() {
+					case reflect.Slice:
+						defer func(field *StructField) {
+							var (
+								relationship           = &Relationship{}
+								toScope                = scope.New(reflect.New(field.Struct.Type).Interface())
+								foreignKeys            []string
+								associationForeignKeys []string
+								elemType               = field.Struct.Type
+							)
+
+							if foreignKey, _ := field.TagSettingsGet("FOREIGNKEY"); foreignKey != "" {
+								foreignKeys = strings.Split(foreignKey, ",")
+							}
+
+							if foreignKey, _ := field.TagSettingsGet("ASSOCIATION_FOREIGNKEY"); foreignKey != "" {
+								associationForeignKeys = strings.Split(foreignKey, ",")
+							} else if foreignKey, _ := field.TagSettingsGet("ASSOCIATIONFOREIGNKEY"); foreignKey != "" {
+								associationForeignKeys = strings.Split(foreignKey, ",")
+							}
+
+							for elemType.Kind() == reflect.Slice || elemType.Kind() == reflect.Ptr {
+								elemType = elemType.Elem()
+							}
+
+							if elemType.Kind() == reflect.Struct {
+								if many2many, _ := field.TagSettingsGet("MANY2MANY"); many2many != "" {
+									relationship.Kind = "many_to_many"
+
+									{ // Foreign Keys for Source
+										joinTableDBNames := []string{}
+
+										if foreignKey, _ := field.TagSettingsGet("JOINTABLE_FOREIGNKEY"); foreignKey != "" {
+											joinTableDBNames = strings.Split(foreignKey, ",")
+										}
+
+										// if no foreign keys defined with tag
+										if len(foreignKeys) == 0 {
+											for _, field := range modelStruct.PrimaryFields {
+												foreignKeys = append(foreignKeys, field.DBName)
+											}
+										}
+
+										for idx, foreignKey := range foreignKeys {
+											if foreignField := getForeignField(foreignKey, modelStruct.StructFields); foreignField != nil {
+												// source foreign keys (db names)
+												relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.DBName)
+
+												// setup join table foreign keys for source
+												if len(joinTableDBNames) > idx {
+													// if defined join table's foreign key
+													relationship.ForeignDBNames = append(relationship.ForeignDBNames, joinTableDBNames[idx])
+												} else {
+													defaultJointableForeignKey := ToColumnName(reflectType.Name()) + "_" + foreignField.DBName
+													relationship.ForeignDBNames = append(relationship.ForeignDBNames, defaultJointableForeignKey)
+												}
+											}
+										}
+									}
+
+									{ // Foreign Keys for Association (Destination)
+										associationJoinTableDBNames := []string{}
+
+										if foreignKey, _ := field.TagSettingsGet("ASSOCIATION_JOINTABLE_FOREIGNKEY"); foreignKey != "" {
+											associationJoinTableDBNames = strings.Split(foreignKey, ",")
+										}
+
+										// if no association foreign keys defined with tag
+										if len(associationForeignKeys) == 0 {
+											for _, field := range toScope.PrimaryFields() {
+												associationForeignKeys = append(associationForeignKeys, field.DBName)
+											}
+										}
+
+										for idx, name := range associationForeignKeys {
+											if field, ok := toScope.FieldByName(name); ok {
+												// association foreign keys (db names)
+												relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, field.DBName)
+
+												// setup join table foreign keys for association
+												if len(associationJoinTableDBNames) > idx {
+													relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, associationJoinTableDBNames[idx])
+												} else {
+													// join table foreign keys for association
+													joinTableDBName := ToColumnName(elemType.Name()) + "_" + field.DBName
+													relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, joinTableDBName)
+												}
+											}
+										}
+									}
+
+									joinTableHandler := JoinTableHandler{}
+									joinTableHandler.Setup(relationship, many2many, reflectType, elemType)
+									relationship.JoinTableHandler = &joinTableHandler
+									field.Relationship = relationship
+								} else {
+									// User has many comments, associationType is User, comment use UserID as foreign key
+									var associationType = reflectType.Name()
+									var toFields = toScope.GetStructFields()
+									relationship.Kind = "has_many"
+
+									if polymorphic, _ := field.TagSettingsGet("POLYMORPHIC"); polymorphic != "" {
+										// Dog has many toys, tag polymorphic is Owner, then associationType is Owner
+										// Toy use OwnerID, OwnerType ('dogs') as foreign key
+										if polymorphicType := getForeignField(polymorphic+"Type", toFields); polymorphicType != nil {
+											associationType = polymorphic
+											relationship.PolymorphicType = polymorphicType.Name
+											relationship.PolymorphicDBName = polymorphicType.DBName
+											// if Dog has multiple set of toys set name of the set (instead of default 'dogs')
+											if value, ok := field.TagSettingsGet("POLYMORPHIC_VALUE"); ok {
+												relationship.PolymorphicValue = value
+											} else {
+												relationship.PolymorphicValue = scope.TableName()
+											}
+											polymorphicType.IsForeignKey = true
+										}
+									}
+
+									// if no foreign keys defined with tag
+									if len(foreignKeys) == 0 {
+										// if no association foreign keys defined with tag
+										if len(associationForeignKeys) == 0 {
+											for _, field := range modelStruct.PrimaryFields {
+												foreignKeys = append(foreignKeys, associationType+field.Name)
+												associationForeignKeys = append(associationForeignKeys, field.Name)
+											}
+										} else {
+											// generate foreign keys from defined association foreign keys
+											for _, scopeFieldName := range associationForeignKeys {
+												if foreignField := getForeignField(scopeFieldName, modelStruct.StructFields); foreignField != nil {
+													foreignKeys = append(foreignKeys, associationType+foreignField.Name)
+													associationForeignKeys = append(associationForeignKeys, foreignField.Name)
+												}
+											}
+										}
+									} else {
+										// generate association foreign keys from foreign keys
+										if len(associationForeignKeys) == 0 {
+											for _, foreignKey := range foreignKeys {
+												if strings.HasPrefix(foreignKey, associationType) {
+													associationForeignKey := strings.TrimPrefix(foreignKey, associationType)
+													if foreignField := getForeignField(associationForeignKey, modelStruct.StructFields); foreignField != nil {
+														associationForeignKeys = append(associationForeignKeys, associationForeignKey)
+													}
+												}
+											}
+											if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
+												associationForeignKeys = []string{scope.PrimaryKey()}
+											}
+										} else if len(foreignKeys) != len(associationForeignKeys) {
+											scope.Err(errors.New("invalid foreign keys, should have same length"))
+											return
+										}
+									}
+
+									for idx, foreignKey := range foreignKeys {
+										if foreignField := getForeignField(foreignKey, toFields); foreignField != nil {
+											if associationField := getForeignField(associationForeignKeys[idx], modelStruct.StructFields); associationField != nil {
+												// mark field as foreignkey, use global lock to avoid race
+												structsLock.Lock()
+												foreignField.IsForeignKey = true
+												structsLock.Unlock()
+
+												// association foreign keys
+												relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, associationField.Name)
+												relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, associationField.DBName)
+
+												// association foreign keys
+												relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.Name)
+												relationship.ForeignDBNames = append(relationship.ForeignDBNames, foreignField.DBName)
+											}
+										}
+									}
+
+									if len(relationship.ForeignFieldNames) != 0 {
+										field.Relationship = relationship
+									}
+								}
+							} else {
+								field.IsNormal = true
+							}
+						}(field)
+					case reflect.Struct:
+						defer func(field *StructField) {
+							var (
+								// user has one profile, associationType is User, profile use UserID as foreign key
+								// user belongs to profile, associationType is Profile, user use ProfileID as foreign key
+								associationType           = reflectType.Name()
+								relationship              = &Relationship{}
+								toScope                   = scope.New(reflect.New(field.Struct.Type).Interface())
+								toFields                  = toScope.GetStructFields()
+								tagForeignKeys            []string
+								tagAssociationForeignKeys []string
+							)
+
+							if foreignKey, _ := field.TagSettingsGet("FOREIGNKEY"); foreignKey != "" {
+								tagForeignKeys = strings.Split(foreignKey, ",")
+							}
+
+							if foreignKey, _ := field.TagSettingsGet("ASSOCIATION_FOREIGNKEY"); foreignKey != "" {
+								tagAssociationForeignKeys = strings.Split(foreignKey, ",")
+							} else if foreignKey, _ := field.TagSettingsGet("ASSOCIATIONFOREIGNKEY"); foreignKey != "" {
+								tagAssociationForeignKeys = strings.Split(foreignKey, ",")
+							}
+
+							if polymorphic, _ := field.TagSettingsGet("POLYMORPHIC"); polymorphic != "" {
+								// Cat has one toy, tag polymorphic is Owner, then associationType is Owner
+								// Toy use OwnerID, OwnerType ('cats') as foreign key
+								if polymorphicType := getForeignField(polymorphic+"Type", toFields); polymorphicType != nil {
+									associationType = polymorphic
+									relationship.PolymorphicType = polymorphicType.Name
+									relationship.PolymorphicDBName = polymorphicType.DBName
+									// if Cat has several different types of toys set name for each (instead of default 'cats')
+									if value, ok := field.TagSettingsGet("POLYMORPHIC_VALUE"); ok {
+										relationship.PolymorphicValue = value
+									} else {
+										relationship.PolymorphicValue = scope.TableName()
+									}
+									polymorphicType.IsForeignKey = true
+								}
+							}
+
+							// Has One
+							{
+								var foreignKeys = tagForeignKeys
+								var associationForeignKeys = tagAssociationForeignKeys
+								// if no foreign keys defined with tag
+								if len(foreignKeys) == 0 {
+									// if no association foreign keys defined with tag
+									if len(associationForeignKeys) == 0 {
+										for _, primaryField := range modelStruct.PrimaryFields {
+											foreignKeys = append(foreignKeys, associationType+primaryField.Name)
+											associationForeignKeys = append(associationForeignKeys, primaryField.Name)
+										}
+									} else {
+										// generate foreign keys form association foreign keys
+										for _, associationForeignKey := range tagAssociationForeignKeys {
+											if foreignField := getForeignField(associationForeignKey, modelStruct.StructFields); foreignField != nil {
+												foreignKeys = append(foreignKeys, associationType+foreignField.Name)
+												associationForeignKeys = append(associationForeignKeys, foreignField.Name)
+											}
+										}
+									}
+								} else {
+									// generate association foreign keys from foreign keys
+									if len(associationForeignKeys) == 0 {
+										for _, foreignKey := range foreignKeys {
+											if strings.HasPrefix(foreignKey, associationType) {
+												associationForeignKey := strings.TrimPrefix(foreignKey, associationType)
+												if foreignField := getForeignField(associationForeignKey, modelStruct.StructFields); foreignField != nil {
+													associationForeignKeys = append(associationForeignKeys, associationForeignKey)
+												}
+											}
+										}
+										if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
+											associationForeignKeys = []string{scope.PrimaryKey()}
+										}
+									} else if len(foreignKeys) != len(associationForeignKeys) {
+										scope.Err(errors.New("invalid foreign keys, should have same length"))
+										return
+									}
+								}
+
+								for idx, foreignKey := range foreignKeys {
+									if foreignField := getForeignField(foreignKey, toFields); foreignField != nil {
+										if scopeField := getForeignField(associationForeignKeys[idx], modelStruct.StructFields); scopeField != nil {
+											// mark field as foreignkey, use global lock to avoid race
+											structsLock.Lock()
+											foreignField.IsForeignKey = true
+											structsLock.Unlock()
+
+											// association foreign keys
+											relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, scopeField.Name)
+											relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, scopeField.DBName)
+
+											// association foreign keys
+											relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.Name)
+											relationship.ForeignDBNames = append(relationship.ForeignDBNames, foreignField.DBName)
+										}
+									}
+								}
+							}
+
+							if len(relationship.ForeignFieldNames) != 0 {
+								relationship.Kind = "has_one"
+								field.Relationship = relationship
+							} else {
+								var foreignKeys = tagForeignKeys
+								var associationForeignKeys = tagAssociationForeignKeys
+
+								if len(foreignKeys) == 0 {
+									// generate foreign keys & association foreign keys
+									if len(associationForeignKeys) == 0 {
+										for _, primaryField := range toScope.PrimaryFields() {
+											foreignKeys = append(foreignKeys, field.Name+primaryField.Name)
+											associationForeignKeys = append(associationForeignKeys, primaryField.Name)
+										}
+									} else {
+										// generate foreign keys with association foreign keys
+										for _, associationForeignKey := range associationForeignKeys {
+											if foreignField := getForeignField(associationForeignKey, toFields); foreignField != nil {
+												foreignKeys = append(foreignKeys, field.Name+foreignField.Name)
+												associationForeignKeys = append(associationForeignKeys, foreignField.Name)
+											}
+										}
+									}
+								} else {
+									// generate foreign keys & association foreign keys
+									if len(associationForeignKeys) == 0 {
+										for _, foreignKey := range foreignKeys {
+											if strings.HasPrefix(foreignKey, field.Name) {
+												associationForeignKey := strings.TrimPrefix(foreignKey, field.Name)
+												if foreignField := getForeignField(associationForeignKey, toFields); foreignField != nil {
+													associationForeignKeys = append(associationForeignKeys, associationForeignKey)
+												}
+											}
+										}
+										if len(associationForeignKeys) == 0 && len(foreignKeys) == 1 {
+											associationForeignKeys = []string{toScope.PrimaryKey()}
+										}
+									} else if len(foreignKeys) != len(associationForeignKeys) {
+										scope.Err(errors.New("invalid foreign keys, should have same length"))
+										return
+									}
+								}
+
+								for idx, foreignKey := range foreignKeys {
+									if foreignField := getForeignField(foreignKey, modelStruct.StructFields); foreignField != nil {
+										if associationField := getForeignField(associationForeignKeys[idx], toFields); associationField != nil {
+											// mark field as foreignkey, use global lock to avoid race
+											structsLock.Lock()
+											foreignField.IsForeignKey = true
+											structsLock.Unlock()
+
+											// association foreign keys
+											relationship.AssociationForeignFieldNames = append(relationship.AssociationForeignFieldNames, associationField.Name)
+											relationship.AssociationForeignDBNames = append(relationship.AssociationForeignDBNames, associationField.DBName)
+
+											// source foreign keys
+											relationship.ForeignFieldNames = append(relationship.ForeignFieldNames, foreignField.Name)
+											relationship.ForeignDBNames = append(relationship.ForeignDBNames, foreignField.DBName)
+										}
+									}
+								}
+
+								if len(relationship.ForeignFieldNames) != 0 {
+									relationship.Kind = "belongs_to"
+									field.Relationship = relationship
+								}
+							}
+						}(field)
+					default:
+						field.IsNormal = true
+					}
+				}
+			}
+
+			// Even it is ignored, also possible to decode db value into the field
+			if value, ok := field.TagSettingsGet("COLUMN"); ok {
+				field.DBName = value
+			} else {
+				field.DBName = ToColumnName(fieldStruct.Name)
+			}
+
+			modelStruct.StructFields = append(modelStruct.StructFields, field)
+		}
+	}
+
+	if len(modelStruct.PrimaryFields) == 0 {
+		if field := getForeignField("id", modelStruct.StructFields); field != nil {
+			field.IsPrimaryKey = true
+			modelStruct.PrimaryFields = append(modelStruct.PrimaryFields, field)
+		}
+	}
+
+	modelStructsMap.Store(hashKey, &modelStruct)
+
+	return &modelStruct
+}
+
+// GetStructFields get model's field structs
+func (scope *Scope) GetStructFields() (fields []*StructField) {
+	return scope.GetModelStruct().StructFields
+}
+
+func parseTagSetting(tags reflect.StructTag) map[string]string {
+	setting := map[string]string{}
+	for _, str := range []string{tags.Get("sql"), tags.Get("gorm")} {
+		if str == "" {
+			continue
+		}
+		tags := strings.Split(str, ";")
+		for _, value := range tags {
+			v := strings.Split(value, ":")
+			k := strings.TrimSpace(strings.ToUpper(v[0]))
+			if len(v) >= 2 {
+				setting[k] = strings.Join(v[1:], ":")
+			} else {
+				setting[k] = k
+			}
+		}
+	}
+	return setting
+}
@@ -0,0 +1,124 @@
+package gorm
+
+import (
+	"bytes"
+	"strings"
+)
+
+// Namer is a function type which is given a string and return a string
+type Namer func(string) string
+
+// NamingStrategy represents naming strategies
+type NamingStrategy struct {
+	DB     Namer
+	Table  Namer
+	Column Namer
+}
+
+// TheNamingStrategy is being initialized with defaultNamingStrategy
+var TheNamingStrategy = &NamingStrategy{
+	DB:     defaultNamer,
+	Table:  defaultNamer,
+	Column: defaultNamer,
+}
+
+// AddNamingStrategy sets the naming strategy
+func AddNamingStrategy(ns *NamingStrategy) {
+	if ns.DB == nil {
+		ns.DB = defaultNamer
+	}
+	if ns.Table == nil {
+		ns.Table = defaultNamer
+	}
+	if ns.Column == nil {
+		ns.Column = defaultNamer
+	}
+	TheNamingStrategy = ns
+}
+
+// DBName alters the given name by DB
+func (ns *NamingStrategy) DBName(name string) string {
+	return ns.DB(name)
+}
+
+// TableName alters the given name by Table
+func (ns *NamingStrategy) TableName(name string) string {
+	return ns.Table(name)
+}
+
+// ColumnName alters the given name by Column
+func (ns *NamingStrategy) ColumnName(name string) string {
+	return ns.Column(name)
+}
+
+// ToDBName convert string to db name
+func ToDBName(name string) string {
+	return TheNamingStrategy.DBName(name)
+}
+
+// ToTableName convert string to table name
+func ToTableName(name string) string {
+	return TheNamingStrategy.TableName(name)
+}
+
+// ToColumnName convert string to db name
+func ToColumnName(name string) string {
+	return TheNamingStrategy.ColumnName(name)
+}
+
+var smap = newSafeMap()
+
+func defaultNamer(name string) string {
+	const (
+		lower = false
+		upper = true
+	)
+
+	if v := smap.Get(name); v != "" {
+		return v
+	}
+
+	if name == "" {
+		return ""
+	}
+
+	var (
+		value                                    = commonInitialismsReplacer.Replace(name)
+		buf                                      = bytes.NewBufferString("")
+		lastCase, currCase, nextCase, nextNumber bool
+	)
+
+	for i, v := range value[:len(value)-1] {
+		nextCase = bool(value[i+1] >= 'A' && value[i+1] <= 'Z')
+		nextNumber = bool(value[i+1] >= '0' && value[i+1] <= '9')
+
+		if i > 0 {
+			if currCase == upper {
+				if lastCase == upper && (nextCase == upper || nextNumber == upper) {
+					buf.WriteRune(v)
+				} else {
+					if value[i-1] != '_' && value[i+1] != '_' {
+						buf.WriteRune('_')
+					}
+					buf.WriteRune(v)
+				}
+			} else {
+				buf.WriteRune(v)
+				if i == len(value)-2 && (nextCase == upper && nextNumber == lower) {
+					buf.WriteRune('_')
+				}
+			}
+		} else {
+			currCase = upper
+			buf.WriteRune(v)
+		}
+		lastCase = currCase
+		currCase = nextCase
+	}
+
+	buf.WriteByte(value[len(value)-1])
+
+	s := strings.ToLower(buf.String())
+	smap.Set(name, s)
+	return s
+}
@@ -0,0 +1,153 @@
+package gorm
+
+import (
+	"fmt"
+)
+
+type search struct {
+	db               *DB
+	whereConditions  []map[string]interface{}
+	orConditions     []map[string]interface{}
+	notConditions    []map[string]interface{}
+	havingConditions []map[string]interface{}
+	joinConditions   []map[string]interface{}
+	initAttrs        []interface{}
+	assignAttrs      []interface{}
+	selects          map[string]interface{}
+	omits            []string
+	orders           []interface{}
+	preload          []searchPreload
+	offset           interface{}
+	limit            interface{}
+	group            string
+	tableName        string
+	raw              bool
+	Unscoped         bool
+	ignoreOrderQuery bool
+}
+
+type searchPreload struct {
+	schema     string
+	conditions []interface{}
+}
+
+func (s *search) clone() *search {
+	clone := *s
+	return &clone
+}
+
+func (s *search) Where(query interface{}, values ...interface{}) *search {
+	s.whereConditions = append(s.whereConditions, map[string]interface{}{"query": query, "args": values})
+	return s
+}
+
+func (s *search) Not(query interface{}, values ...interface{}) *search {
+	s.notConditions = append(s.notConditions, map[string]interface{}{"query": query, "args": values})
+	return s
+}
+
+func (s *search) Or(query interface{}, values ...interface{}) *search {
+	s.orConditions = append(s.orConditions, map[string]interface{}{"query": query, "args": values})
+	return s
+}
+
+func (s *search) Attrs(attrs ...interface{}) *search {
+	s.initAttrs = append(s.initAttrs, toSearchableMap(attrs...))
+	return s
+}
+
+func (s *search) Assign(attrs ...interface{}) *search {
+	s.assignAttrs = append(s.assignAttrs, toSearchableMap(attrs...))
+	return s
+}
+
+func (s *search) Order(value interface{}, reorder ...bool) *search {
+	if len(reorder) > 0 && reorder[0] {
+		s.orders = []interface{}{}
+	}
+
+	if value != nil && value != "" {
+		s.orders = append(s.orders, value)
+	}
+	return s
+}
+
+func (s *search) Select(query interface{}, args ...interface{}) *search {
+	s.selects = map[string]interface{}{"query": query, "args": args}
+	return s
+}
+
+func (s *search) Omit(columns ...string) *search {
+	s.omits = columns
+	return s
+}
+
+func (s *search) Limit(limit interface{}) *search {
+	s.limit = limit
+	return s
+}
+
+func (s *search) Offset(offset interface{}) *search {
+	s.offset = offset
+	return s
+}
+
+func (s *search) Group(query string) *search {
+	s.group = s.getInterfaceAsSQL(query)
+	return s
+}
+
+func (s *search) Having(query interface{}, values ...interface{}) *search {
+	if val, ok := query.(*SqlExpr); ok {
+		s.havingConditions = append(s.havingConditions, map[string]interface{}{"query": val.expr, "args": val.args})
+	} else {
+		s.havingConditions = append(s.havingConditions, map[string]interface{}{"query": query, "args": values})
+	}
+	return s
+}
+
+func (s *search) Joins(query string, values ...interface{}) *search {
+	s.joinConditions = append(s.joinConditions, map[string]interface{}{"query": query, "args": values})
+	return s
+}
+
+func (s *search) Preload(schema string, values ...interface{}) *search {
+	var preloads []searchPreload
+	for _, preload := range s.preload {
+		if preload.schema != schema {
+			preloads = append(preloads, preload)
+		}
+	}
+	preloads = append(preloads, searchPreload{schema, values})
+	s.preload = preloads
+	return s
+}
+
+func (s *search) Raw(b bool) *search {
+	s.raw = b
+	return s
+}
+
+func (s *search) unscoped() *search {
+	s.Unscoped = true
+	return s
+}
+
+func (s *search) Table(name string) *search {
+	s.tableName = name
+	return s
+}
+
+func (s *search) getInterfaceAsSQL(value interface{}) (str string) {
+	switch value.(type) {
+	case string, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
+		str = fmt.Sprintf("%v", value)
+	default:
+		s.db.AddError(ErrInvalidSQL)
+	}
+
+	if str == "-1" {
+		return ""
+	}
+	return
+}
@@ -0,0 +1,5 @@
+dialects=("postgres" "mysql" "mssql" "sqlite")
+
+for dialect in "${dialects[@]}" ; do
+    DEBUG=false GORM_DIALECT=${dialect} go test
+done
@@ -0,0 +1,226 @@
+package gorm
+
+import (
+	"database/sql/driver"
+	"fmt"
+	"reflect"
+	"regexp"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+)
+
+// NowFunc returns current time, this function is exported in order to be able
+// to give the flexibility to the developer to customize it according to their
+// needs, e.g:
+//    gorm.NowFunc = func() time.Time {
+//      return time.Now().UTC()
+//    }
+var NowFunc = func() time.Time {
+	return time.Now()
+}
+
+// Copied from golint
+var commonInitialisms = []string{"API", "ASCII", "CPU", "CSS", "DNS", "EOF", "GUID", "HTML", "HTTP", "HTTPS", "ID", "IP", "JSON", "LHS", "QPS", "RAM", "RHS", "RPC", "SLA", "SMTP", "SSH", "TLS", "TTL", "UID", "UI", "UUID", "URI", "URL", "UTF8", "VM", "XML", "XSRF", "XSS"}
+var commonInitialismsReplacer *strings.Replacer
+
+var goSrcRegexp = regexp.MustCompile(`jinzhu/gorm(@.*)?/.*.go`)
+var goTestRegexp = regexp.MustCompile(`jinzhu/gorm(@.*)?/.*test.go`)
+
+func init() {
+	var commonInitialismsForReplacer []string
+	for _, initialism := range commonInitialisms {
+		commonInitialismsForReplacer = append(commonInitialismsForReplacer, initialism, strings.Title(strings.ToLower(initialism)))
+	}
+	commonInitialismsReplacer = strings.NewReplacer(commonInitialismsForReplacer...)
+}
+
+type safeMap struct {
+	m map[string]string
+	l *sync.RWMutex
+}
+
+func (s *safeMap) Set(key string, value string) {
+	s.l.Lock()
+	defer s.l.Unlock()
+	s.m[key] = value
+}
+
+func (s *safeMap) Get(key string) string {
+	s.l.RLock()
+	defer s.l.RUnlock()
+	return s.m[key]
+}
+
+func newSafeMap() *safeMap {
+	return &safeMap{l: new(sync.RWMutex), m: make(map[string]string)}
+}
+
+// SQL expression
+type SqlExpr struct {
+	expr string
+	args []interface{}
+}
+
+// Expr generate raw SQL expression, for example:
+//     DB.Model(&product).Update("price", gorm.Expr("price * ? + ?", 2, 100))
+func Expr(expression string, args ...interface{}) *SqlExpr {
+	return &SqlExpr{expr: expression, args: args}
+}
+
+func indirect(reflectValue reflect.Value) reflect.Value {
+	for reflectValue.Kind() == reflect.Ptr {
+		reflectValue = reflectValue.Elem()
+	}
+	return reflectValue
+}
+
+func toQueryMarks(primaryValues [][]interface{}) string {
+	var results []string
+
+	for _, primaryValue := range primaryValues {
+		var marks []string
+		for range primaryValue {
+			marks = append(marks, "?")
+		}
+
+		if len(marks) > 1 {
+			results = append(results, fmt.Sprintf("(%v)", strings.Join(marks, ",")))
+		} else {
+			results = append(results, strings.Join(marks, ""))
+		}
+	}
+	return strings.Join(results, ",")
+}
+
+func toQueryCondition(scope *Scope, columns []string) string {
+	var newColumns []string
+	for _, column := range columns {
+		newColumns = append(newColumns, scope.Quote(column))
+	}
+
+	if len(columns) > 1 {
+		return fmt.Sprintf("(%v)", strings.Join(newColumns, ","))
+	}
+	return strings.Join(newColumns, ",")
+}
+
+func toQueryValues(values [][]interface{}) (results []interface{}) {
+	for _, value := range values {
+		for _, v := range value {
+			results = append(results, v)
+		}
+	}
+	return
+}
+
+func fileWithLineNum() string {
+	for i := 2; i < 15; i++ {
+		_, file, line, ok := runtime.Caller(i)
+		if ok && (!goSrcRegexp.MatchString(file) || goTestRegexp.MatchString(file)) {
+			return fmt.Sprintf("%v:%v", file, line)
+		}
+	}
+	return ""
+}
+
+func isBlank(value reflect.Value) bool {
+	switch value.Kind() {
+	case reflect.String:
+		return value.Len() == 0
+	case reflect.Bool:
+		return !value.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return value.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return value.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return value.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return value.IsNil()
+	}
+
+	return reflect.DeepEqual(value.Interface(), reflect.Zero(value.Type()).Interface())
+}
+
+func toSearchableMap(attrs ...interface{}) (result interface{}) {
+	if len(attrs) > 1 {
+		if str, ok := attrs[0].(string); ok {
+			result = map[string]interface{}{str: attrs[1]}
+		}
+	} else if len(attrs) == 1 {
+		if attr, ok := attrs[0].(map[string]interface{}); ok {
+			result = attr
+		}
+
+		if attr, ok := attrs[0].(interface{}); ok {
+			result = attr
+		}
+	}
+	return
+}
+
+func equalAsString(a interface{}, b interface{}) bool {
+	return toString(a) == toString(b)
+}
+
+func toString(str interface{}) string {
+	if values, ok := str.([]interface{}); ok {
+		var results []string
+		for _, value := range values {
+			results = append(results, toString(value))
+		}
+		return strings.Join(results, "_")
+	} else if bytes, ok := str.([]byte); ok {
+		return string(bytes)
+	} else if reflectValue := reflect.Indirect(reflect.ValueOf(str)); reflectValue.IsValid() {
+		return fmt.Sprintf("%v", reflectValue.Interface())
+	}
+	return ""
+}
+
+func makeSlice(elemType reflect.Type) interface{} {
+	if elemType.Kind() == reflect.Slice {
+		elemType = elemType.Elem()
+	}
+	sliceType := reflect.SliceOf(elemType)
+	slice := reflect.New(sliceType)
+	slice.Elem().Set(reflect.MakeSlice(sliceType, 0, 0))
+	return slice.Interface()
+}
+
+func strInSlice(a string, list []string) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}
+
+// getValueFromFields return given fields's value
+func getValueFromFields(value reflect.Value, fieldNames []string) (results []interface{}) {
+	// If value is a nil pointer, Indirect returns a zero Value!
+	// Therefor we need to check for a zero value,
+	// as FieldByName could panic
+	if indirectValue := reflect.Indirect(value); indirectValue.IsValid() {
+		for _, fieldName := range fieldNames {
+			if fieldValue := reflect.Indirect(indirectValue.FieldByName(fieldName)); fieldValue.IsValid() {
+				result := fieldValue.Interface()
+				if r, ok := result.(driver.Valuer); ok {
+					result, _ = r.Value()
+				}
+				results = append(results, result)
+			}
+		}
+	}
+	return
+}
+
+func addExtraSpaceIfExist(str string) string {
+	if str != "" {
+		return " " + str
+	}
+	return ""
+}
@@ -0,0 +1,154 @@
+# use the default golang container from Docker Hub
+box: golang
+
+services:
+    - name: mariadb
+      id: mariadb:latest
+      env:
+          MYSQL_DATABASE: gorm
+          MYSQL_USER: gorm
+          MYSQL_PASSWORD: gorm
+          MYSQL_RANDOM_ROOT_PASSWORD: "yes"
+    - name: mysql
+      id: mysql:latest
+      env:
+          MYSQL_DATABASE: gorm
+          MYSQL_USER: gorm
+          MYSQL_PASSWORD: gorm
+          MYSQL_RANDOM_ROOT_PASSWORD: "yes"
+    - name: mysql57
+      id: mysql:5.7
+      env:
+          MYSQL_DATABASE: gorm
+          MYSQL_USER: gorm
+          MYSQL_PASSWORD: gorm
+          MYSQL_RANDOM_ROOT_PASSWORD: "yes"
+    - name: mysql56
+      id: mysql:5.6
+      env:
+          MYSQL_DATABASE: gorm
+          MYSQL_USER: gorm
+          MYSQL_PASSWORD: gorm
+          MYSQL_RANDOM_ROOT_PASSWORD: "yes"
+    - name: postgres
+      id: postgres:latest
+      env:
+          POSTGRES_USER: gorm
+          POSTGRES_PASSWORD: gorm
+          POSTGRES_DB: gorm
+    - name: postgres96
+      id: postgres:9.6
+      env:
+          POSTGRES_USER: gorm
+          POSTGRES_PASSWORD: gorm
+          POSTGRES_DB: gorm
+    - name: postgres95
+      id: postgres:9.5
+      env:
+          POSTGRES_USER: gorm
+          POSTGRES_PASSWORD: gorm
+          POSTGRES_DB: gorm
+    - name: postgres94
+      id: postgres:9.4
+      env:
+          POSTGRES_USER: gorm
+          POSTGRES_PASSWORD: gorm
+          POSTGRES_DB: gorm
+    - name: postgres93
+      id: postgres:9.3
+      env:
+          POSTGRES_USER: gorm
+          POSTGRES_PASSWORD: gorm
+          POSTGRES_DB: gorm
+    - name: mssql
+      id: mcmoe/mssqldocker:latest
+      env:
+        ACCEPT_EULA: Y
+        SA_PASSWORD: LoremIpsum86
+        MSSQL_DB: gorm
+        MSSQL_USER: gorm
+        MSSQL_PASSWORD: LoremIpsum86
+
+# The steps that will be executed in the build pipeline
+build:
+    # The steps that will be executed on build
+    steps:
+        # Sets the go workspace and places you package
+        # at the right place in the workspace tree
+        - setup-go-workspace
+
+        # Gets the dependencies
+        - script:
+                name: go get
+                code: |
+                    cd $WERCKER_SOURCE_DIR
+                    go version
+                    go get -t -v ./...
+
+        # Build the project
+        - script:
+                name: go build
+                code: |
+                    go build ./...
+
+        # Test the project
+        - script:
+                name: test sqlite
+                code: |
+                    go test -race -v ./...
+
+        - script:
+                name: test mariadb
+                code: |
+                    GORM_DIALECT=mysql GORM_DSN="gorm:gorm@tcp(mariadb:3306)/gorm?charset=utf8&parseTime=True" go test -race ./...
+
+        - script:
+                name: test mysql
+                code: |
+                    GORM_DIALECT=mysql GORM_DSN="gorm:gorm@tcp(mysql:3306)/gorm?charset=utf8&parseTime=True" go test -race ./...
+
+        - script:
+                name: test mysql5.7
+                code: |
+                    GORM_DIALECT=mysql GORM_DSN="gorm:gorm@tcp(mysql57:3306)/gorm?charset=utf8&parseTime=True" go test -race ./...
+
+        - script:
+                name: test mysql5.6
+                code: |
+                    GORM_DIALECT=mysql GORM_DSN="gorm:gorm@tcp(mysql56:3306)/gorm?charset=utf8&parseTime=True" go test -race ./...
+
+        - script:
+                name: test postgres
+                code: |
+                    GORM_DIALECT=postgres GORM_DSN="host=postgres user=gorm password=gorm DB.name=gorm port=5432 sslmode=disable" go test -race ./...
+
+        - script:
+                name: test postgres96
+                code: |
+                    GORM_DIALECT=postgres GORM_DSN="host=postgres96 user=gorm password=gorm DB.name=gorm port=5432 sslmode=disable" go test -race ./...
+
+        - script:
+                name: test postgres95
+                code: |
+                    GORM_DIALECT=postgres GORM_DSN="host=postgres95 user=gorm password=gorm DB.name=gorm port=5432 sslmode=disable" go test -race ./...
+
+        - script:
+                name: test postgres94
+                code: |
+                    GORM_DIALECT=postgres GORM_DSN="host=postgres94 user=gorm password=gorm DB.name=gorm port=5432 sslmode=disable" go test -race ./...
+
+        - script:
+                name: test postgres93
+                code: |
+                    GORM_DIALECT=postgres GORM_DSN="host=postgres93 user=gorm password=gorm DB.name=gorm port=5432 sslmode=disable" go test -race ./...
+
+        - script:
+                name: test mssql
+                code: |
+                    GORM_DIALECT=mssql GORM_DSN="sqlserver://gorm:LoremIpsum86@mssql:1433?database=gorm" go test -race ./...
+
+        - script:
+                name: codecov
+                code: |
+                    go test -race -coverprofile=coverage.txt -covermode=atomic ./...
+                    bash <(curl -s https://codecov.io/bash)
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 - Jinzhu
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
@@ -0,0 +1,55 @@
+# Inflection
+
+Inflection pluralizes and singularizes English nouns
+
+[![wercker status](https://app.wercker.com/status/f8c7432b097d1f4ce636879670be0930/s/master "wercker status")](https://app.wercker.com/project/byKey/f8c7432b097d1f4ce636879670be0930)
+
+## Basic Usage
+
+```go
+inflection.Plural("person") => "people"
+inflection.Plural("Person") => "People"
+inflection.Plural("PERSON") => "PEOPLE"
+inflection.Plural("bus")    => "buses"
+inflection.Plural("BUS")    => "BUSES"
+inflection.Plural("Bus")    => "Buses"
+
+inflection.Singular("people") => "person"
+inflection.Singular("People") => "Person"
+inflection.Singular("PEOPLE") => "PERSON"
+inflection.Singular("buses")  => "bus"
+inflection.Singular("BUSES")  => "BUS"
+inflection.Singular("Buses")  => "Bus"
+
+inflection.Plural("FancyPerson") => "FancyPeople"
+inflection.Singular("FancyPeople") => "FancyPerson"
+```
+
+## Register Rules
+
+Standard rules are from Rails's ActiveSupport (https://github.com/rails/rails/blob/master/activesupport/lib/active_support/inflections.rb)
+
+If you want to register more rules, follow:
+
+```
+inflection.AddUncountable("fish")
+inflection.AddIrregular("person", "people")
+inflection.AddPlural("(bu)s$", "${1}ses") # "bus" => "buses" / "BUS" => "BUSES" / "Bus" => "Buses"
+inflection.AddSingular("(bus)(es)?$", "${1}") # "buses" => "bus" / "Buses" => "Bus" / "BUSES" => "BUS"
+```
+
+## Contributing
+
+You can help to make the project better, check out [http://gorm.io/contribute.html](http://gorm.io/contribute.html) for things you can do.
+
+## Author
+
+**jinzhu**
+
+* <http://github.com/jinzhu>
+* <wosmvp@gmail.com>
+* <http://twitter.com/zhangjinzhu>
+
+## License
+
+Released under the [MIT License](http://www.opensource.org/licenses/MIT).
@@ -0,0 +1 @@
+module github.com/jinzhu/inflection
@@ -0,0 +1,273 @@
+/*
+Package inflection pluralizes and singularizes English nouns.
+
+		inflection.Plural("person") => "people"
+		inflection.Plural("Person") => "People"
+		inflection.Plural("PERSON") => "PEOPLE"
+
+		inflection.Singular("people") => "person"
+		inflection.Singular("People") => "Person"
+		inflection.Singular("PEOPLE") => "PERSON"
+
+		inflection.Plural("FancyPerson") => "FancydPeople"
+		inflection.Singular("FancyPeople") => "FancydPerson"
+
+Standard rules are from Rails's ActiveSupport (https://github.com/rails/rails/blob/master/activesupport/lib/active_support/inflections.rb)
+
+If you want to register more rules, follow:
+
+		inflection.AddUncountable("fish")
+		inflection.AddIrregular("person", "people")
+		inflection.AddPlural("(bu)s$", "${1}ses") # "bus" => "buses" / "BUS" => "BUSES" / "Bus" => "Buses"
+		inflection.AddSingular("(bus)(es)?$", "${1}") # "buses" => "bus" / "Buses" => "Bus" / "BUSES" => "BUS"
+*/
+package inflection
+
+import (
+	"regexp"
+	"strings"
+)
+
+type inflection struct {
+	regexp  *regexp.Regexp
+	replace string
+}
+
+// Regular is a regexp find replace inflection
+type Regular struct {
+	find    string
+	replace string
+}
+
+// Irregular is a hard replace inflection,
+// containing both singular and plural forms
+type Irregular struct {
+	singular string
+	plural   string
+}
+
+// RegularSlice is a slice of Regular inflections
+type RegularSlice []Regular
+
+// IrregularSlice is a slice of Irregular inflections
+type IrregularSlice []Irregular
+
+var pluralInflections = RegularSlice{
+	{"([a-z])$", "${1}s"},
+	{"s$", "s"},
+	{"^(ax|test)is$", "${1}es"},
+	{"(octop|vir)us$", "${1}i"},
+	{"(octop|vir)i$", "${1}i"},
+	{"(alias|status)$", "${1}es"},
+	{"(bu)s$", "${1}ses"},
+	{"(buffal|tomat)o$", "${1}oes"},
+	{"([ti])um$", "${1}a"},
+	{"([ti])a$", "${1}a"},
+	{"sis$", "ses"},
+	{"(?:([^f])fe|([lr])f)$", "${1}${2}ves"},
+	{"(hive)$", "${1}s"},
+	{"([^aeiouy]|qu)y$", "${1}ies"},
+	{"(x|ch|ss|sh)$", "${1}es"},
+	{"(matr|vert|ind)(?:ix|ex)$", "${1}ices"},
+	{"^(m|l)ouse$", "${1}ice"},
+	{"^(m|l)ice$", "${1}ice"},
+	{"^(ox)$", "${1}en"},
+	{"^(oxen)$", "${1}"},
+	{"(quiz)$", "${1}zes"},
+}
+
+var singularInflections = RegularSlice{
+	{"s$", ""},
+	{"(ss)$", "${1}"},
+	{"(n)ews$", "${1}ews"},
+	{"([ti])a$", "${1}um"},
+	{"((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)(sis|ses)$", "${1}sis"},
+	{"(^analy)(sis|ses)$", "${1}sis"},
+	{"([^f])ves$", "${1}fe"},
+	{"(hive)s$", "${1}"},
+	{"(tive)s$", "${1}"},
+	{"([lr])ves$", "${1}f"},
+	{"([^aeiouy]|qu)ies$", "${1}y"},
+	{"(s)eries$", "${1}eries"},
+	{"(m)ovies$", "${1}ovie"},
+	{"(c)ookies$", "${1}ookie"},
+	{"(x|ch|ss|sh)es$", "${1}"},
+	{"^(m|l)ice$", "${1}ouse"},
+	{"(bus)(es)?$", "${1}"},
+	{"(o)es$", "${1}"},
+	{"(shoe)s$", "${1}"},
+	{"(cris|test)(is|es)$", "${1}is"},
+	{"^(a)x[ie]s$", "${1}xis"},
+	{"(octop|vir)(us|i)$", "${1}us"},
+	{"(alias|status)(es)?$", "${1}"},
+	{"^(ox)en", "${1}"},
+	{"(vert|ind)ices$", "${1}ex"},
+	{"(matr)ices$", "${1}ix"},
+	{"(quiz)zes$", "${1}"},
+	{"(database)s$", "${1}"},
+}
+
+var irregularInflections = IrregularSlice{
+	{"person", "people"},
+	{"man", "men"},
+	{"child", "children"},
+	{"sex", "sexes"},
+	{"move", "moves"},
+	{"mombie", "mombies"},
+}
+
+var uncountableInflections = []string{"equipment", "information", "rice", "money", "species", "series", "fish", "sheep", "jeans", "police", "evidence"}
+
+var compiledPluralMaps []inflection
+var compiledSingularMaps []inflection
+
+func compile() {
+	compiledPluralMaps = []inflection{}
+	compiledSingularMaps = []inflection{}
+	for _, uncountable := range uncountableInflections {
+		inf := inflection{
+			regexp:  regexp.MustCompile("^(?i)(" + uncountable + ")$"),
+			replace: "${1}",
+		}
+		compiledPluralMaps = append(compiledPluralMaps, inf)
+		compiledSingularMaps = append(compiledSingularMaps, inf)
+	}
+
+	for _, value := range irregularInflections {
+		infs := []inflection{
+			inflection{regexp: regexp.MustCompile(strings.ToUpper(value.singular) + "$"), replace: strings.ToUpper(value.plural)},
+			inflection{regexp: regexp.MustCompile(strings.Title(value.singular) + "$"), replace: strings.Title(value.plural)},
+			inflection{regexp: regexp.MustCompile(value.singular + "$"), replace: value.plural},
+		}
+		compiledPluralMaps = append(compiledPluralMaps, infs...)
+	}
+
+	for _, value := range irregularInflections {
+		infs := []inflection{
+			inflection{regexp: regexp.MustCompile(strings.ToUpper(value.plural) + "$"), replace: strings.ToUpper(value.singular)},
+			inflection{regexp: regexp.MustCompile(strings.Title(value.plural) + "$"), replace: strings.Title(value.singular)},
+			inflection{regexp: regexp.MustCompile(value.plural + "$"), replace: value.singular},
+		}
+		compiledSingularMaps = append(compiledSingularMaps, infs...)
+	}
+
+	for i := len(pluralInflections) - 1; i >= 0; i-- {
+		value := pluralInflections[i]
+		infs := []inflection{
+			inflection{regexp: regexp.MustCompile(strings.ToUpper(value.find)), replace: strings.ToUpper(value.replace)},
+			inflection{regexp: regexp.MustCompile(value.find), replace: value.replace},
+			inflection{regexp: regexp.MustCompile("(?i)" + value.find), replace: value.replace},
+		}
+		compiledPluralMaps = append(compiledPluralMaps, infs...)
+	}
+
+	for i := len(singularInflections) - 1; i >= 0; i-- {
+		value := singularInflections[i]
+		infs := []inflection{
+			inflection{regexp: regexp.MustCompile(strings.ToUpper(value.find)), replace: strings.ToUpper(value.replace)},
+			inflection{regexp: regexp.MustCompile(value.find), replace: value.replace},
+			inflection{regexp: regexp.MustCompile("(?i)" + value.find), replace: value.replace},
+		}
+		compiledSingularMaps = append(compiledSingularMaps, infs...)
+	}
+}
+
+func init() {
+	compile()
+}
+
+// AddPlural adds a plural inflection
+func AddPlural(find, replace string) {
+	pluralInflections = append(pluralInflections, Regular{find, replace})
+	compile()
+}
+
+// AddSingular adds a singular inflection
+func AddSingular(find, replace string) {
+	singularInflections = append(singularInflections, Regular{find, replace})
+	compile()
+}
+
+// AddIrregular adds an irregular inflection
+func AddIrregular(singular, plural string) {
+	irregularInflections = append(irregularInflections, Irregular{singular, plural})
+	compile()
+}
+
+// AddUncountable adds an uncountable inflection
+func AddUncountable(values ...string) {
+	uncountableInflections = append(uncountableInflections, values...)
+	compile()
+}
+
+// GetPlural retrieves the plural inflection values
+func GetPlural() RegularSlice {
+	plurals := make(RegularSlice, len(pluralInflections))
+	copy(plurals, pluralInflections)
+	return plurals
+}
+
+// GetSingular retrieves the singular inflection values
+func GetSingular() RegularSlice {
+	singulars := make(RegularSlice, len(singularInflections))
+	copy(singulars, singularInflections)
+	return singulars
+}
+
+// GetIrregular retrieves the irregular inflection values
+func GetIrregular() IrregularSlice {
+	irregular := make(IrregularSlice, len(irregularInflections))
+	copy(irregular, irregularInflections)
+	return irregular
+}
+
+// GetUncountable retrieves the uncountable inflection values
+func GetUncountable() []string {
+	uncountables := make([]string, len(uncountableInflections))
+	copy(uncountables, uncountableInflections)
+	return uncountables
+}
+
+// SetPlural sets the plural inflections slice
+func SetPlural(inflections RegularSlice) {
+	pluralInflections = inflections
+	compile()
+}
+
+// SetSingular sets the singular inflections slice
+func SetSingular(inflections RegularSlice) {
+	singularInflections = inflections
+	compile()
+}
+
+// SetIrregular sets the irregular inflections slice
+func SetIrregular(inflections IrregularSlice) {
+	irregularInflections = inflections
+	compile()
+}
+
+// SetUncountable sets the uncountable inflections slice
+func SetUncountable(inflections []string) {
+	uncountableInflections = inflections
+	compile()
+}
+
+// Plural converts a word to its plural form
+func Plural(str string) string {
+	for _, inflection := range compiledPluralMaps {
+		if inflection.regexp.MatchString(str) {
+			return inflection.regexp.ReplaceAllString(str, inflection.replace)
+		}
+	}
+	return str
+}
+
+// Singular converts a word to its singular form
+func Singular(str string) string {
+	for _, inflection := range compiledSingularMaps {
+		if inflection.regexp.MatchString(str) {
+			return inflection.regexp.ReplaceAllString(str, inflection.replace)
+		}
+	}
+	return str
+}
@@ -0,0 +1,23 @@
+box: golang
+
+build:
+  steps:
+    - setup-go-workspace
+
+    # Gets the dependencies
+    - script:
+        name: go get
+        code: |
+          go get
+
+    # Build the project
+    - script:
+        name: go build
+        code: |
+          go build ./...
+
+    # Test the project
+    - script:
+        name: go test
+        code: |
+          go test ./...
@@ -0,0 +1 @@
+.DS_Store
@@ -0,0 +1,8 @@
+language: go
+
+go:
+  - 1.x
+
+os:
+  - linux
+  - osx
@@ -0,0 +1,23 @@
+Copyright (c) 2013 John Barton
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
@@ -0,0 +1,188 @@
+# GoDotEnv [![Build Status](https://travis-ci.org/joho/godotenv.svg?branch=master)](https://travis-ci.org/joho/godotenv) [![Build status](https://ci.appveyor.com/api/projects/status/9v40vnfvvgde64u4?svg=true)](https://ci.appveyor.com/project/joho/godotenv) [![Go Report Card](https://goreportcard.com/badge/github.com/joho/godotenv)](https://goreportcard.com/report/github.com/joho/godotenv)
+
+A Go (golang) port of the Ruby dotenv project (which loads env vars from a .env file)
+
+From the original Library:
+
+> Storing configuration in the environment is one of the tenets of a twelve-factor app. Anything that is likely to change between deployment environments–such as resource handles for databases or credentials for external services–should be extracted from the code into environment variables.
+>
+> But it is not always practical to set environment variables on development machines or continuous integration servers where multiple projects are run. Dotenv load variables from a .env file into ENV when the environment is bootstrapped.
+
+It can be used as a library (for loading in env for your own daemons etc) or as a bin command.
+
+There is test coverage and CI for both linuxish and windows environments, but I make no guarantees about the bin version working on windows.
+
+## Installation
+
+As a library
+
+```shell
+go get github.com/joho/godotenv
+```
+
+or if you want to use it as a bin command
+```shell
+go get github.com/joho/godotenv/cmd/godotenv
+```
+
+## Usage
+
+Add your application configuration to your `.env` file in the root of your project:
+
+```shell
+S3_BUCKET=YOURS3BUCKET
+SECRET_KEY=YOURSECRETKEYGOESHERE
+```
+
+Then in your Go app you can do something like
+
+```go
+package main
+
+import (
+    "github.com/joho/godotenv"
+    "log"
+    "os"
+)
+
+func main() {
+  err := godotenv.Load()
+  if err != nil {
+    log.Fatal("Error loading .env file")
+  }
+
+  s3Bucket := os.Getenv("S3_BUCKET")
+  secretKey := os.Getenv("SECRET_KEY")
+
+  // now do something with s3 or whatever
+}
+```
+
+If you're even lazier than that, you can just take advantage of the autoload package which will read in `.env` on import
+
+```go
+import _ "github.com/joho/godotenv/autoload"
+```
+
+While `.env` in the project root is the default, you don't have to be constrained, both examples below are 100% legit
+
+```go
+_ = godotenv.Load("somerandomfile")
+_ = godotenv.Load("filenumberone.env", "filenumbertwo.env")
+```
+
+If you want to be really fancy with your env file you can do comments and exports (below is a valid env file)
+
+```shell
+# I am a comment and that is OK
+SOME_VAR=someval
+FOO=BAR # comments at line end are OK too
+export BAR=BAZ
+```
+
+Or finally you can do YAML(ish) style
+
+```yaml
+FOO: bar
+BAR: baz
+```
+
+as a final aside, if you don't want godotenv munging your env you can just get a map back instead
+
+```go
+var myEnv map[string]string
+myEnv, err := godotenv.Read()
+
+s3Bucket := myEnv["S3_BUCKET"]
+```
+
+... or from an `io.Reader` instead of a local file
+
+```go
+reader := getRemoteFile()
+myEnv, err := godotenv.Parse(reader)
+```
+
+... or from a `string` if you so desire
+
+```go
+content := getRemoteFileContent()
+myEnv, err := godotenv.Unmarshal(content)
+```
+
+### Precendence & Conventions
+
+Existing envs take precendence of envs that are loaded later.
+
+The [convention](https://github.com/bkeepers/dotenv#what-other-env-files-can-i-use)
+for managing multiple environments (i.e. development, test, production)
+is to create an env named `{YOURAPP}_ENV` and load envs in this order:
+
+```go
+env := os.Getenv("FOO_ENV")
+if "" == env {
+  env = "development"
+}
+
+godotenv.Load(".env." + env + ".local")
+if "test" != env {
+  godotenv.Load(".env.local")
+}
+godotenv.Load(".env." + env)
+godotenv.Load() // The Original .env
+```
+
+If you need to, you can also use `godotenv.Overload()` to defy this convention
+and overwrite existing envs instead of only supplanting them. Use with caution.
+
+### Command Mode
+
+Assuming you've installed the command as above and you've got `$GOPATH/bin` in your `$PATH`
+
+```
+godotenv -f /some/path/to/.env some_command with some args
+```
+
+If you don't specify `-f` it will fall back on the default of loading `.env` in `PWD`
+
+### Writing Env Files
+
+Godotenv can also write a map representing the environment to a correctly-formatted and escaped file
+
+```go
+env, err := godotenv.Unmarshal("KEY=value")
+err := godotenv.Write(env, "./.env")
+```
+
+... or to a string
+
+```go
+env, err := godotenv.Unmarshal("KEY=value")
+content, err := godotenv.Marshal(env)
+```
+
+## Contributing
+
+Contributions are most welcome! The parser itself is pretty stupidly naive and I wouldn't be surprised if it breaks with edge cases.
+
+*code changes without tests will not be accepted*
+
+1. Fork it
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Commit your changes (`git commit -am 'Added some feature'`)
+4. Push to the branch (`git push origin my-new-feature`)
+5. Create new Pull Request
+
+## Releases
+
+Releases should follow [Semver](http://semver.org/) though the first couple of releases are `v1` and `v1.1`.
+
+Use [annotated tags for all releases](https://github.com/joho/godotenv/issues/30). Example `git tag -a v1.2.1`
+
+## CI
+
+Linux: [![Build Status](https://travis-ci.org/joho/godotenv.svg?branch=master)](https://travis-ci.org/joho/godotenv) Windows: [![Build status](https://ci.appveyor.com/api/projects/status/9v40vnfvvgde64u4)](https://ci.appveyor.com/project/joho/godotenv)
+
+## Who?
+
+The original library [dotenv](https://github.com/bkeepers/dotenv) was written by [Brandon Keepers](http://opensoul.org/), and this port was done by [John Barton](https://johnbarton.co/) based off the tests/fixtures in the original library.
@@ -0,0 +1,358 @@
+// Package godotenv is a go port of the ruby dotenv library (https://github.com/bkeepers/dotenv)
+//
+// Examples/readme can be found on the github page at https://github.com/joho/godotenv
+//
+// The TL;DR is that you make a .env file that looks something like
+//
+// 		SOME_ENV_VAR=somevalue
+//
+// and then in your go code you can call
+//
+// 		godotenv.Load()
+//
+// and all the env vars declared in .env will be available through os.Getenv("SOME_ENV_VAR")
+package godotenv
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"regexp"
+	"sort"
+	"strings"
+)
+
+const doubleQuoteSpecialChars = "\\\n\r\"!$`"
+
+// Load will read your env file(s) and load them into ENV for this process.
+//
+// Call this function as close as possible to the start of your program (ideally in main)
+//
+// If you call Load without any args it will default to loading .env in the current path
+//
+// You can otherwise tell it which files to load (there can be more than one) like
+//
+//		godotenv.Load("fileone", "filetwo")
+//
+// It's important to note that it WILL NOT OVERRIDE an env variable that already exists - consider the .env file to set dev vars or sensible defaults
+func Load(filenames ...string) (err error) {
+	filenames = filenamesOrDefault(filenames)
+
+	for _, filename := range filenames {
+		err = loadFile(filename, false)
+		if err != nil {
+			return // return early on a spazout
+		}
+	}
+	return
+}
+
+// Overload will read your env file(s) and load them into ENV for this process.
+//
+// Call this function as close as possible to the start of your program (ideally in main)
+//
+// If you call Overload without any args it will default to loading .env in the current path
+//
+// You can otherwise tell it which files to load (there can be more than one) like
+//
+//		godotenv.Overload("fileone", "filetwo")
+//
+// It's important to note this WILL OVERRIDE an env variable that already exists - consider the .env file to forcefilly set all vars.
+func Overload(filenames ...string) (err error) {
+	filenames = filenamesOrDefault(filenames)
+
+	for _, filename := range filenames {
+		err = loadFile(filename, true)
+		if err != nil {
+			return // return early on a spazout
+		}
+	}
+	return
+}
+
+// Read all env (with same file loading semantics as Load) but return values as
+// a map rather than automatically writing values into env
+func Read(filenames ...string) (envMap map[string]string, err error) {
+	filenames = filenamesOrDefault(filenames)
+	envMap = make(map[string]string)
+
+	for _, filename := range filenames {
+		individualEnvMap, individualErr := readFile(filename)
+
+		if individualErr != nil {
+			err = individualErr
+			return // return early on a spazout
+		}
+
+		for key, value := range individualEnvMap {
+			envMap[key] = value
+		}
+	}
+
+	return
+}
+
+// Parse reads an env file from io.Reader, returning a map of keys and values.
+func Parse(r io.Reader) (envMap map[string]string, err error) {
+	envMap = make(map[string]string)
+
+	var lines []string
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err = scanner.Err(); err != nil {
+		return
+	}
+
+	for _, fullLine := range lines {
+		if !isIgnoredLine(fullLine) {
+			var key, value string
+			key, value, err = parseLine(fullLine, envMap)
+
+			if err != nil {
+				return
+			}
+			envMap[key] = value
+		}
+	}
+	return
+}
+
+//Unmarshal reads an env file from a string, returning a map of keys and values.
+func Unmarshal(str string) (envMap map[string]string, err error) {
+	return Parse(strings.NewReader(str))
+}
+
+// Exec loads env vars from the specified filenames (empty map falls back to default)
+// then executes the cmd specified.
+//
+// Simply hooks up os.Stdin/err/out to the command and calls Run()
+//
+// If you want more fine grained control over your command it's recommended
+// that you use `Load()` or `Read()` and the `os/exec` package yourself.
+func Exec(filenames []string, cmd string, cmdArgs []string) error {
+	Load(filenames...)
+
+	command := exec.Command(cmd, cmdArgs...)
+	command.Stdin = os.Stdin
+	command.Stdout = os.Stdout
+	command.Stderr = os.Stderr
+	return command.Run()
+}
+
+// Write serializes the given environment and writes it to a file
+func Write(envMap map[string]string, filename string) error {
+	content, err := Marshal(envMap)
+	if err != nil {
+		return err
+	}
+	file, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	_, err = file.WriteString(content)
+	if err != nil {
+		return err
+	}
+	file.Sync()
+	return err
+}
+
+// Marshal outputs the given environment as a dotenv-formatted environment file.
+// Each line is in the format: KEY="VALUE" where VALUE is backslash-escaped.
+func Marshal(envMap map[string]string) (string, error) {
+	lines := make([]string, 0, len(envMap))
+	for k, v := range envMap {
+		lines = append(lines, fmt.Sprintf(`%s="%s"`, k, doubleQuoteEscape(v)))
+	}
+	sort.Strings(lines)
+	return strings.Join(lines, "\n"), nil
+}
+
+func filenamesOrDefault(filenames []string) []string {
+	if len(filenames) == 0 {
+		return []string{".env"}
+	}
+	return filenames
+}
+
+func loadFile(filename string, overload bool) error {
+	envMap, err := readFile(filename)
+	if err != nil {
+		return err
+	}
+
+	currentEnv := map[string]bool{}
+	rawEnv := os.Environ()
+	for _, rawEnvLine := range rawEnv {
+		key := strings.Split(rawEnvLine, "=")[0]
+		currentEnv[key] = true
+	}
+
+	for key, value := range envMap {
+		if !currentEnv[key] || overload {
+			os.Setenv(key, value)
+		}
+	}
+
+	return nil
+}
+
+func readFile(filename string) (envMap map[string]string, err error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return
+	}
+	defer file.Close()
+
+	return Parse(file)
+}
+
+var exportRegex = regexp.MustCompile(`^\s*(?:export\s+)?(.*?)\s*$`)
+
+func parseLine(line string, envMap map[string]string) (key string, value string, err error) {
+	if len(line) == 0 {
+		err = errors.New("zero length string")
+		return
+	}
+
+	// ditch the comments (but keep quoted hashes)
+	if strings.Contains(line, "#") {
+		segmentsBetweenHashes := strings.Split(line, "#")
+		quotesAreOpen := false
+		var segmentsToKeep []string
+		for _, segment := range segmentsBetweenHashes {
+			if strings.Count(segment, "\"") == 1 || strings.Count(segment, "'") == 1 {
+				if quotesAreOpen {
+					quotesAreOpen = false
+					segmentsToKeep = append(segmentsToKeep, segment)
+				} else {
+					quotesAreOpen = true
+				}
+			}
+
+			if len(segmentsToKeep) == 0 || quotesAreOpen {
+				segmentsToKeep = append(segmentsToKeep, segment)
+			}
+		}
+
+		line = strings.Join(segmentsToKeep, "#")
+	}
+
+	firstEquals := strings.Index(line, "=")
+	firstColon := strings.Index(line, ":")
+	splitString := strings.SplitN(line, "=", 2)
+	if firstColon != -1 && (firstColon < firstEquals || firstEquals == -1) {
+		//this is a yaml-style line
+		splitString = strings.SplitN(line, ":", 2)
+	}
+
+	if len(splitString) != 2 {
+		err = errors.New("Can't separate key from value")
+		return
+	}
+
+	// Parse the key
+	key = splitString[0]
+	if strings.HasPrefix(key, "export") {
+		key = strings.TrimPrefix(key, "export")
+	}
+	key = strings.TrimSpace(key)
+
+	key = exportRegex.ReplaceAllString(splitString[0], "$1")
+
+	// Parse the value
+	value = parseValue(splitString[1], envMap)
+	return
+}
+
+var (
+	singleQuotesRegex  = regexp.MustCompile(`\A'(.*)'\z`)
+	doubleQuotesRegex  = regexp.MustCompile(`\A"(.*)"\z`)
+	escapeRegex        = regexp.MustCompile(`\\.`)
+	unescapeCharsRegex = regexp.MustCompile(`\\([^$])`)
+)
+
+func parseValue(value string, envMap map[string]string) string {
+
+	// trim
+	value = strings.Trim(value, " ")
+
+	// check if we've got quoted values or possible escapes
+	if len(value) > 1 {
+		singleQuotes := singleQuotesRegex.FindStringSubmatch(value)
+
+		doubleQuotes := doubleQuotesRegex.FindStringSubmatch(value)
+
+		if singleQuotes != nil || doubleQuotes != nil {
+			// pull the quotes off the edges
+			value = value[1 : len(value)-1]
+		}
+
+		if doubleQuotes != nil {
+			// expand newlines
+			value = escapeRegex.ReplaceAllStringFunc(value, func(match string) string {
+				c := strings.TrimPrefix(match, `\`)
+				switch c {
+				case "n":
+					return "\n"
+				case "r":
+					return "\r"
+				default:
+					return match
+				}
+			})
+			// unescape characters
+			value = unescapeCharsRegex.ReplaceAllString(value, "$1")
+		}
+
+		if singleQuotes == nil {
+			value = expandVariables(value, envMap)
+		}
+	}
+
+	return value
+}
+
+var expandVarRegex = regexp.MustCompile(`(\\)?(\$)(\()?\{?([A-Z0-9_]+)?\}?`)
+
+func expandVariables(v string, m map[string]string) string {
+	return expandVarRegex.ReplaceAllStringFunc(v, func(s string) string {
+		submatch := expandVarRegex.FindStringSubmatch(s)
+
+		if submatch == nil {
+			return s
+		}
+		if submatch[1] == "\\" || submatch[2] == "(" {
+			return submatch[0][1:]
+		} else if submatch[4] != "" {
+			return m[submatch[4]]
+		}
+		return s
+	})
+}
+
+func isIgnoredLine(line string) bool {
+	trimmedLine := strings.TrimSpace(line)
+	return len(trimmedLine) == 0 || strings.HasPrefix(trimmedLine, "#")
+}
+
+func doubleQuoteEscape(line string) string {
+	for _, c := range doubleQuoteSpecialChars {
+		toReplace := "\\" + string(c)
+		if c == '\n' {
+			toReplace = `\n`
+		}
+		if c == '\r' {
+			toReplace = `\r`
+		}
+		line = strings.Replace(line, string(c), toReplace, -1)
+	}
+	return line
+}
@@ -0,0 +1,3 @@
+# This source code refers to The Go Authors for copyright purposes.
+# The master list of authors is in the main Go distribution,
+# visible at https://tip.golang.org/AUTHORS.
@@ -0,0 +1,3 @@
+# This source code was written by the Go contributors.
+# The master list of contributors is in the main Go distribution,
+# visible at https://tip.golang.org/CONTRIBUTORS.
@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
@@ -0,0 +1,22 @@
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.
@@ -0,0 +1,35 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bcrypt
+
+import "encoding/base64"
+
+const alphabet = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+
+var bcEncoding = base64.NewEncoding(alphabet)
+
+func base64Encode(src []byte) []byte {
+	n := bcEncoding.EncodedLen(len(src))
+	dst := make([]byte, n)
+	bcEncoding.Encode(dst, src)
+	for dst[n-1] == '=' {
+		n--
+	}
+	return dst[:n]
+}
+
+func base64Decode(src []byte) ([]byte, error) {
+	numOfEquals := 4 - (len(src) % 4)
+	for i := 0; i < numOfEquals; i++ {
+		src = append(src, '=')
+	}
+
+	dst := make([]byte, bcEncoding.DecodedLen(len(src)))
+	n, err := bcEncoding.Decode(dst, src)
+	if err != nil {
+		return nil, err
+	}
+	return dst[:n], nil
+}
@@ -0,0 +1,295 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package bcrypt implements Provos and Mazières's bcrypt adaptive hashing
+// algorithm. See http://www.usenix.org/event/usenix99/provos/provos.pdf
+package bcrypt
+
+// The code is a port of Provos and Mazières's C implementation.
+import (
+	"crypto/rand"
+	"crypto/subtle"
+	"errors"
+	"fmt"
+	"io"
+	"strconv"
+
+	"golang.org/x/crypto/blowfish"
+)
+
+const (
+	MinCost     int = 4  // the minimum allowable cost as passed in to GenerateFromPassword
+	MaxCost     int = 31 // the maximum allowable cost as passed in to GenerateFromPassword
+	DefaultCost int = 10 // the cost that will actually be set if a cost below MinCost is passed into GenerateFromPassword
+)
+
+// The error returned from CompareHashAndPassword when a password and hash do
+// not match.
+var ErrMismatchedHashAndPassword = errors.New("crypto/bcrypt: hashedPassword is not the hash of the given password")
+
+// The error returned from CompareHashAndPassword when a hash is too short to
+// be a bcrypt hash.
+var ErrHashTooShort = errors.New("crypto/bcrypt: hashedSecret too short to be a bcrypted password")
+
+// The error returned from CompareHashAndPassword when a hash was created with
+// a bcrypt algorithm newer than this implementation.
+type HashVersionTooNewError byte
+
+func (hv HashVersionTooNewError) Error() string {
+	return fmt.Sprintf("crypto/bcrypt: bcrypt algorithm version '%c' requested is newer than current version '%c'", byte(hv), majorVersion)
+}
+
+// The error returned from CompareHashAndPassword when a hash starts with something other than '$'
+type InvalidHashPrefixError byte
+
+func (ih InvalidHashPrefixError) Error() string {
+	return fmt.Sprintf("crypto/bcrypt: bcrypt hashes must start with '$', but hashedSecret started with '%c'", byte(ih))
+}
+
+type InvalidCostError int
+
+func (ic InvalidCostError) Error() string {
+	return fmt.Sprintf("crypto/bcrypt: cost %d is outside allowed range (%d,%d)", int(ic), int(MinCost), int(MaxCost))
+}
+
+const (
+	majorVersion       = '2'
+	minorVersion       = 'a'
+	maxSaltSize        = 16
+	maxCryptedHashSize = 23
+	encodedSaltSize    = 22
+	encodedHashSize    = 31
+	minHashSize        = 59
+)
+
+// magicCipherData is an IV for the 64 Blowfish encryption calls in
+// bcrypt(). It's the string "OrpheanBeholderScryDoubt" in big-endian bytes.
+var magicCipherData = []byte{
+	0x4f, 0x72, 0x70, 0x68,
+	0x65, 0x61, 0x6e, 0x42,
+	0x65, 0x68, 0x6f, 0x6c,
+	0x64, 0x65, 0x72, 0x53,
+	0x63, 0x72, 0x79, 0x44,
+	0x6f, 0x75, 0x62, 0x74,
+}
+
+type hashed struct {
+	hash  []byte
+	salt  []byte
+	cost  int // allowed range is MinCost to MaxCost
+	major byte
+	minor byte
+}
+
+// GenerateFromPassword returns the bcrypt hash of the password at the given
+// cost. If the cost given is less than MinCost, the cost will be set to
+// DefaultCost, instead. Use CompareHashAndPassword, as defined in this package,
+// to compare the returned hashed password with its cleartext version.
+func GenerateFromPassword(password []byte, cost int) ([]byte, error) {
+	p, err := newFromPassword(password, cost)
+	if err != nil {
+		return nil, err
+	}
+	return p.Hash(), nil
+}
+
+// CompareHashAndPassword compares a bcrypt hashed password with its possible
+// plaintext equivalent. Returns nil on success, or an error on failure.
+func CompareHashAndPassword(hashedPassword, password []byte) error {
+	p, err := newFromHash(hashedPassword)
+	if err != nil {
+		return err
+	}
+
+	otherHash, err := bcrypt(password, p.cost, p.salt)
+	if err != nil {
+		return err
+	}
+
+	otherP := &hashed{otherHash, p.salt, p.cost, p.major, p.minor}
+	if subtle.ConstantTimeCompare(p.Hash(), otherP.Hash()) == 1 {
+		return nil
+	}
+
+	return ErrMismatchedHashAndPassword
+}
+
+// Cost returns the hashing cost used to create the given hashed
+// password. When, in the future, the hashing cost of a password system needs
+// to be increased in order to adjust for greater computational power, this
+// function allows one to establish which passwords need to be updated.
+func Cost(hashedPassword []byte) (int, error) {
+	p, err := newFromHash(hashedPassword)
+	if err != nil {
+		return 0, err
+	}
+	return p.cost, nil
+}
+
+func newFromPassword(password []byte, cost int) (*hashed, error) {
+	if cost < MinCost {
+		cost = DefaultCost
+	}
+	p := new(hashed)
+	p.major = majorVersion
+	p.minor = minorVersion
+
+	err := checkCost(cost)
+	if err != nil {
+		return nil, err
+	}
+	p.cost = cost
+
+	unencodedSalt := make([]byte, maxSaltSize)
+	_, err = io.ReadFull(rand.Reader, unencodedSalt)
+	if err != nil {
+		return nil, err
+	}
+
+	p.salt = base64Encode(unencodedSalt)
+	hash, err := bcrypt(password, p.cost, p.salt)
+	if err != nil {
+		return nil, err
+	}
+	p.hash = hash
+	return p, err
+}
+
+func newFromHash(hashedSecret []byte) (*hashed, error) {
+	if len(hashedSecret) < minHashSize {
+		return nil, ErrHashTooShort
+	}
+	p := new(hashed)
+	n, err := p.decodeVersion(hashedSecret)
+	if err != nil {
+		return nil, err
+	}
+	hashedSecret = hashedSecret[n:]
+	n, err = p.decodeCost(hashedSecret)
+	if err != nil {
+		return nil, err
+	}
+	hashedSecret = hashedSecret[n:]
+
+	// The "+2" is here because we'll have to append at most 2 '=' to the salt
+	// when base64 decoding it in expensiveBlowfishSetup().
+	p.salt = make([]byte, encodedSaltSize, encodedSaltSize+2)
+	copy(p.salt, hashedSecret[:encodedSaltSize])
+
+	hashedSecret = hashedSecret[encodedSaltSize:]
+	p.hash = make([]byte, len(hashedSecret))
+	copy(p.hash, hashedSecret)
+
+	return p, nil
+}
+
+func bcrypt(password []byte, cost int, salt []byte) ([]byte, error) {
+	cipherData := make([]byte, len(magicCipherData))
+	copy(cipherData, magicCipherData)
+
+	c, err := expensiveBlowfishSetup(password, uint32(cost), salt)
+	if err != nil {
+		return nil, err
+	}
+
+	for i := 0; i < 24; i += 8 {
+		for j := 0; j < 64; j++ {
+			c.Encrypt(cipherData[i:i+8], cipherData[i:i+8])
+		}
+	}
+
+	// Bug compatibility with C bcrypt implementations. We only encode 23 of
+	// the 24 bytes encrypted.
+	hsh := base64Encode(cipherData[:maxCryptedHashSize])
+	return hsh, nil
+}
+
+func expensiveBlowfishSetup(key []byte, cost uint32, salt []byte) (*blowfish.Cipher, error) {
+	csalt, err := base64Decode(salt)
+	if err != nil {
+		return nil, err
+	}
+
+	// Bug compatibility with C bcrypt implementations. They use the trailing
+	// NULL in the key string during expansion.
+	// We copy the key to prevent changing the underlying array.
+	ckey := append(key[:len(key):len(key)], 0)
+
+	c, err := blowfish.NewSaltedCipher(ckey, csalt)
+	if err != nil {
+		return nil, err
+	}
+
+	var i, rounds uint64
+	rounds = 1 << cost
+	for i = 0; i < rounds; i++ {
+		blowfish.ExpandKey(ckey, c)
+		blowfish.ExpandKey(csalt, c)
+	}
+
+	return c, nil
+}
+
+func (p *hashed) Hash() []byte {
+	arr := make([]byte, 60)
+	arr[0] = '$'
+	arr[1] = p.major
+	n := 2
+	if p.minor != 0 {
+		arr[2] = p.minor
+		n = 3
+	}
+	arr[n] = '$'
+	n++
+	copy(arr[n:], []byte(fmt.Sprintf("%02d", p.cost)))
+	n += 2
+	arr[n] = '$'
+	n++
+	copy(arr[n:], p.salt)
+	n += encodedSaltSize
+	copy(arr[n:], p.hash)
+	n += encodedHashSize
+	return arr[:n]
+}
+
+func (p *hashed) decodeVersion(sbytes []byte) (int, error) {
+	if sbytes[0] != '$' {
+		return -1, InvalidHashPrefixError(sbytes[0])
+	}
+	if sbytes[1] > majorVersion {
+		return -1, HashVersionTooNewError(sbytes[1])
+	}
+	p.major = sbytes[1]
+	n := 3
+	if sbytes[2] != '$' {
+		p.minor = sbytes[2]
+		n++
+	}
+	return n, nil
+}
+
+// sbytes should begin where decodeVersion left off.
+func (p *hashed) decodeCost(sbytes []byte) (int, error) {
+	cost, err := strconv.Atoi(string(sbytes[0:2]))
+	if err != nil {
+		return -1, err
+	}
+	err = checkCost(cost)
+	if err != nil {
+		return -1, err
+	}
+	p.cost = cost
+	return 3, nil
+}
+
+func (p *hashed) String() string {
+	return fmt.Sprintf("&{hash: %#v, salt: %#v, cost: %d, major: %c, minor: %c}", string(p.hash), p.salt, p.cost, p.major, p.minor)
+}
+
+func checkCost(cost int) error {
+	if cost < MinCost || cost > MaxCost {
+		return InvalidCostError(cost)
+	}
+	return nil
+}
@@ -0,0 +1,159 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package blowfish
+
+// getNextWord returns the next big-endian uint32 value from the byte slice
+// at the given position in a circular manner, updating the position.
+func getNextWord(b []byte, pos *int) uint32 {
+	var w uint32
+	j := *pos
+	for i := 0; i < 4; i++ {
+		w = w<<8 | uint32(b[j])
+		j++
+		if j >= len(b) {
+			j = 0
+		}
+	}
+	*pos = j
+	return w
+}
+
+// ExpandKey performs a key expansion on the given *Cipher. Specifically, it
+// performs the Blowfish algorithm's key schedule which sets up the *Cipher's
+// pi and substitution tables for calls to Encrypt. This is used, primarily,
+// by the bcrypt package to reuse the Blowfish key schedule during its
+// set up. It's unlikely that you need to use this directly.
+func ExpandKey(key []byte, c *Cipher) {
+	j := 0
+	for i := 0; i < 18; i++ {
+		// Using inlined getNextWord for performance.
+		var d uint32
+		for k := 0; k < 4; k++ {
+			d = d<<8 | uint32(key[j])
+			j++
+			if j >= len(key) {
+				j = 0
+			}
+		}
+		c.p[i] ^= d
+	}
+
+	var l, r uint32
+	for i := 0; i < 18; i += 2 {
+		l, r = encryptBlock(l, r, c)
+		c.p[i], c.p[i+1] = l, r
+	}
+
+	for i := 0; i < 256; i += 2 {
+		l, r = encryptBlock(l, r, c)
+		c.s0[i], c.s0[i+1] = l, r
+	}
+	for i := 0; i < 256; i += 2 {
+		l, r = encryptBlock(l, r, c)
+		c.s1[i], c.s1[i+1] = l, r
+	}
+	for i := 0; i < 256; i += 2 {
+		l, r = encryptBlock(l, r, c)
+		c.s2[i], c.s2[i+1] = l, r
+	}
+	for i := 0; i < 256; i += 2 {
+		l, r = encryptBlock(l, r, c)
+		c.s3[i], c.s3[i+1] = l, r
+	}
+}
+
+// This is similar to ExpandKey, but folds the salt during the key
+// schedule. While ExpandKey is essentially expandKeyWithSalt with an all-zero
+// salt passed in, reusing ExpandKey turns out to be a place of inefficiency
+// and specializing it here is useful.
+func expandKeyWithSalt(key []byte, salt []byte, c *Cipher) {
+	j := 0
+	for i := 0; i < 18; i++ {
+		c.p[i] ^= getNextWord(key, &j)
+	}
+
+	j = 0
+	var l, r uint32
+	for i := 0; i < 18; i += 2 {
+		l ^= getNextWord(salt, &j)
+		r ^= getNextWord(salt, &j)
+		l, r = encryptBlock(l, r, c)
+		c.p[i], c.p[i+1] = l, r
+	}
+
+	for i := 0; i < 256; i += 2 {
+		l ^= getNextWord(salt, &j)
+		r ^= getNextWord(salt, &j)
+		l, r = encryptBlock(l, r, c)
+		c.s0[i], c.s0[i+1] = l, r
+	}
+
+	for i := 0; i < 256; i += 2 {
+		l ^= getNextWord(salt, &j)
+		r ^= getNextWord(salt, &j)
+		l, r = encryptBlock(l, r, c)
+		c.s1[i], c.s1[i+1] = l, r
+	}
+
+	for i := 0; i < 256; i += 2 {
+		l ^= getNextWord(salt, &j)
+		r ^= getNextWord(salt, &j)
+		l, r = encryptBlock(l, r, c)
+		c.s2[i], c.s2[i+1] = l, r
+	}
+
+	for i := 0; i < 256; i += 2 {
+		l ^= getNextWord(salt, &j)
+		r ^= getNextWord(salt, &j)
+		l, r = encryptBlock(l, r, c)
+		c.s3[i], c.s3[i+1] = l, r
+	}
+}
+
+func encryptBlock(l, r uint32, c *Cipher) (uint32, uint32) {
+	xl, xr := l, r
+	xl ^= c.p[0]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[1]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[2]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[3]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[4]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[5]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[6]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[7]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[8]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[9]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[10]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[11]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[12]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[13]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[14]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[15]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[16]
+	xr ^= c.p[17]
+	return xr, xl
+}
+
+func decryptBlock(l, r uint32, c *Cipher) (uint32, uint32) {
+	xl, xr := l, r
+	xl ^= c.p[17]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[16]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[15]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[14]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[13]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[12]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[11]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[10]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[9]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[8]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[7]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[6]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[5]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[4]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[3]
+	xr ^= ((c.s0[byte(xl>>24)] + c.s1[byte(xl>>16)]) ^ c.s2[byte(xl>>8)]) + c.s3[byte(xl)] ^ c.p[2]
+	xl ^= ((c.s0[byte(xr>>24)] + c.s1[byte(xr>>16)]) ^ c.s2[byte(xr>>8)]) + c.s3[byte(xr)] ^ c.p[1]
+	xr ^= c.p[0]
+	return xr, xl
+}
@@ -0,0 +1,99 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package blowfish implements Bruce Schneier's Blowfish encryption algorithm.
+//
+// Blowfish is a legacy cipher and its short block size makes it vulnerable to
+// birthday bound attacks (see https://sweet32.info). It should only be used
+// where compatibility with legacy systems, not security, is the goal.
+//
+// Deprecated: any new system should use AES (from crypto/aes, if necessary in
+// an AEAD mode like crypto/cipher.NewGCM) or XChaCha20-Poly1305 (from
+// golang.org/x/crypto/chacha20poly1305).
+package blowfish
+
+// The code is a port of Bruce Schneier's C implementation.
+// See https://www.schneier.com/blowfish.html.
+
+import "strconv"
+
+// The Blowfish block size in bytes.
+const BlockSize = 8
+
+// A Cipher is an instance of Blowfish encryption using a particular key.
+type Cipher struct {
+	p              [18]uint32
+	s0, s1, s2, s3 [256]uint32
+}
+
+type KeySizeError int
+
+func (k KeySizeError) Error() string {
+	return "crypto/blowfish: invalid key size " + strconv.Itoa(int(k))
+}
+
+// NewCipher creates and returns a Cipher.
+// The key argument should be the Blowfish key, from 1 to 56 bytes.
+func NewCipher(key []byte) (*Cipher, error) {
+	var result Cipher
+	if k := len(key); k < 1 || k > 56 {
+		return nil, KeySizeError(k)
+	}
+	initCipher(&result)
+	ExpandKey(key, &result)
+	return &result, nil
+}
+
+// NewSaltedCipher creates a returns a Cipher that folds a salt into its key
+// schedule. For most purposes, NewCipher, instead of NewSaltedCipher, is
+// sufficient and desirable. For bcrypt compatibility, the key can be over 56
+// bytes.
+func NewSaltedCipher(key, salt []byte) (*Cipher, error) {
+	if len(salt) == 0 {
+		return NewCipher(key)
+	}
+	var result Cipher
+	if k := len(key); k < 1 {
+		return nil, KeySizeError(k)
+	}
+	initCipher(&result)
+	expandKeyWithSalt(key, salt, &result)
+	return &result, nil
+}
+
+// BlockSize returns the Blowfish block size, 8 bytes.
+// It is necessary to satisfy the Block interface in the
+// package "crypto/cipher".
+func (c *Cipher) BlockSize() int { return BlockSize }
+
+// Encrypt encrypts the 8-byte buffer src using the key k
+// and stores the result in dst.
+// Note that for amounts of data larger than a block,
+// it is not safe to just call Encrypt on successive blocks;
+// instead, use an encryption mode like CBC (see crypto/cipher/cbc.go).
+func (c *Cipher) Encrypt(dst, src []byte) {
+	l := uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3])
+	r := uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7])
+	l, r = encryptBlock(l, r, c)
+	dst[0], dst[1], dst[2], dst[3] = byte(l>>24), byte(l>>16), byte(l>>8), byte(l)
+	dst[4], dst[5], dst[6], dst[7] = byte(r>>24), byte(r>>16), byte(r>>8), byte(r)
+}
+
+// Decrypt decrypts the 8-byte buffer src using the key k
+// and stores the result in dst.
+func (c *Cipher) Decrypt(dst, src []byte) {
+	l := uint32(src[0])<<24 | uint32(src[1])<<16 | uint32(src[2])<<8 | uint32(src[3])
+	r := uint32(src[4])<<24 | uint32(src[5])<<16 | uint32(src[6])<<8 | uint32(src[7])
+	l, r = decryptBlock(l, r, c)
+	dst[0], dst[1], dst[2], dst[3] = byte(l>>24), byte(l>>16), byte(l>>8), byte(l)
+	dst[4], dst[5], dst[6], dst[7] = byte(r>>24), byte(r>>16), byte(r>>8), byte(r)
+}
+
+func initCipher(c *Cipher) {
+	copy(c.p[0:], p[0:])
+	copy(c.s0[0:], s0[0:])
+	copy(c.s1[0:], s1[0:])
+	copy(c.s2[0:], s2[0:])
+	copy(c.s3[0:], s3[0:])
+}
--- a/Show More
+++ b/Show More