jwt

README

JWT Middleware for Gin Framework

This is a middleware for Gin framework.

It uses jwt-go to provide a jwt authentication middleware. It provides additional handler functions to provide the login api that will generate the token and an additional refresh handler that can be used to refresh tokens.

Install

Install gin-gwt v1 version if jwt-go using v2 version. To get the package, execute:

$ go get gopkg.in/appleboy/gin-jwt.v1

To import this package, add the following line to your code:

import "gopkg.in/appleboy/gin-jwt.v1"

Example

Please see server example file.

package main

import (
  "gopkg.in/appleboy/gin-jwt.v1"
  "github.com/fvbock/endless"
  "github.com/gin-gonic/gin"
  "os"
  "time"
)

func HelloHandler(c *gin.Context) {
  c.JSON(200, gin.H{
    "text": "Hello World.",
  })
}

func main() {
  port := os.Getenv("PORT")
  r := gin.New()
  r.Use(gin.Logger())
  r.Use(gin.Recovery())

  if port == "" {
    port = "8000"
  }

  // the jwt middleware
  authMiddleware := &jwt.GinJWTMiddleware{
    Realm:      "test zone",
    Key:        []byte("secret key"),
    Timeout:    time.Hour,
    MaxRefresh: time.Hour * 24,
    Authenticator: func(userId string, password string, c *gin.Context) (string, bool) {
      if (userId == "admin" && password == "admin") || (userId == "test" && password == "test") {
        return userId, true
      }

      return userId, false
    },
    Authorizator: func(userId string, c *gin.Context) bool {
      if userId == "admin" {
        return true
      }

      return false
    },
    Unauthorized: func(c *gin.Context, code int, message string) {
      c.JSON(code, gin.H{
        "code":    code,
        "message": message,
      })
    },
  }

  r.POST("/login", authMiddleware.LoginHandler)

  auth := r.Group("/auth")
  auth.Use(authMiddleware.MiddlewareFunc())
  {
    auth.GET("/hello", HelloHandler)
    auth.GET("/refresh_token", authMiddleware.RefreshHandler)
  }

  endless.ListenAndServe(":"+port, r)
}

Demo

Please run example/server.go file and listen 8000 port.

$ go run example/server.go

Download and install httpie CLI HTTP client.

Login API:

$ http -v --json POST localhost:8000/login username=admin password=admin

Output screenshot

Refresh token API:

$ http -v -f GET localhost:8000/auth/refresh_token "Authorization:Bearer xxxxxxxxx"  "Content-Type: application/json"

Output screenshot

Hello world

Please login as admin and password as admin

$ http -f GET localhost:8000/auth/hello "Authorization:Bearer xxxxxxxxx"  "Content-Type: application/json"

Response message 200 OK:

HTTP/1.1 200 OK
Content-Length: 24
Content-Type: application/json; charset=utf-8
Date: Sat, 19 Mar 2016 03:02:57 GMT

{
    "text": "Hello World."
}

Authorization

Please login as test and password as test

$ http -f GET localhost:8000/auth/hello "Authorization:Bearer xxxxxxxxx"  "Content-Type: application/json"

Response message 403 Forbidden:

HTTP/1.1 403 Forbidden
Content-Length: 62
Content-Type: application/json; charset=utf-8
Date: Sat, 19 Mar 2016 03:05:40 GMT
Www-Authenticate: JWT realm=test zone

{
    "code": 403,
    "message": "You don't have permission to access."
}

Documentation

Index

• func ExtractClaims(c *gin.Context) map[string]interface{}
• type GinJWTMiddleware
  • func (mw *GinJWTMiddleware) LoginHandler(c *gin.Context)
  • func (mw *GinJWTMiddleware) MiddlewareFunc() gin.HandlerFunc
  • func (mw *GinJWTMiddleware) MiddlewareInit() error
  • func (mw *GinJWTMiddleware) RefreshHandler(c *gin.Context)
  • func (mw *GinJWTMiddleware) TokenGenerator(userID string) string
• type Login

Functions

func ExtractClaims

func ExtractClaims(c *gin.Context) map[string]interface{}

ExtractClaims help to extract the JWT claims

Types

type GinJWTMiddleware

type GinJWTMiddleware struct {
	// Realm name to display to the user. Required.
	Realm string

	// signing algorithm - possible values are HS256, HS384, HS512
	// Optional, default is HS256.
	SigningAlgorithm string

	// Secret key used for signing. Required.
	Key []byte

	// Duration that a jwt token is valid. Optional, defaults to one hour.
	Timeout time.Duration

	// This field allows clients to refresh their token until MaxRefresh has passed.
	// Note that clients can refresh their token in the last moment of MaxRefresh.
	// This means that the maximum validity timespan for a token is MaxRefresh + Timeout.
	// Optional, defaults to 0 meaning not refreshable.
	MaxRefresh time.Duration

	// Callback function that should perform the authentication of the user based on userId and
	// password. Must return true on success, false on failure. Required.
	// Option return user id, if so, user id will be stored in Claim Array.
	Authenticator func(userId string, password string, c *gin.Context) (string, bool)

	// Callback function that should perform the authorization of the authenticated user. Called
	// only after an authentication success. Must return true on success, false on failure.
	// Optional, default to success.
	Authorizator func(userId string, c *gin.Context) bool

	// Callback function that will be called during login.
	// Using this function it is possible to add additional payload data to the webtoken.
	// The data is then made available during requests via c.Get("JWT_PAYLOAD").
	// Note that the payload is not encrypted.
	// The attributes mentioned on jwt.io can't be used as keys for the map.
	// Optional, by default no additional data will be set.
	PayloadFunc func(userId string) map[string]interface{}

	// User can define own Unauthorized func.
	Unauthorized func(*gin.Context, int, string)
}

GinJWTMiddleware provides a Json-Web-Token authentication implementation. On failure, a 401 HTTP response is returned. On success, the wrapped middleware is called, and the userId is made available as c.Get("userId").(string). Users can get a token by posting a json request to LoginHandler. The token then needs to be passed in the Authentication header. Example: Authorization:Bearer XXX_TOKEN_XXX#!/usr/bin/env

func (*GinJWTMiddleware) LoginHandler

func (mw *GinJWTMiddleware) LoginHandler(c *gin.Context)

LoginHandler can be used by clients to get a jwt token. Payload needs to be json in the form of {"username": "USERNAME", "password": "PASSWORD"}. Reply will be of the form {"token": "TOKEN"}.

func (*GinJWTMiddleware) MiddlewareFunc

func (mw *GinJWTMiddleware) MiddlewareFunc() gin.HandlerFunc

MiddlewareFunc makes GinJWTMiddleware implement the Middleware interface.

func (*GinJWTMiddleware) MiddlewareInit

func (mw *GinJWTMiddleware) MiddlewareInit() error

MiddlewareInit initialize jwt configs.

func (*GinJWTMiddleware) RefreshHandler

func (mw *GinJWTMiddleware) RefreshHandler(c *gin.Context)

RefreshHandler can be used to refresh a token. The token still needs to be valid on refresh. Shall be put under an endpoint that is using the GinJWTMiddleware. Reply will be of the form {"token": "TOKEN"}.

func (*GinJWTMiddleware) TokenGenerator

func (mw *GinJWTMiddleware) TokenGenerator(userID string) string

TokenGenerator handler that clients can use to get a jwt token.

type Login

type Login struct {
	Username string `form:"username" json:"username" binding:"required"`
	Password string `form:"password" json:"password" binding:"required"`
}

Login form structure.