Awesome
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.
Security Issue
Simple HS256 JWT token brute force cracker. Effective only to crack JWT tokens with weak secrets. Recommendation: Use strong long secrets or RS256
tokens. See the jwt-cracker repository.
Usage
Download and install using go module:
export GO111MODULE=on
go get github.com/appleboy/gin-jwt/v2
Import it in your code:
import "github.com/appleboy/gin-jwt/v2"
Download and install without using go module:
go get github.com/appleboy/gin-jwt
Import it in your code:
import "github.com/appleboy/gin-jwt"
Example
Please see the example file and you can use ExtractClaims
to fetch user data.
package main
import (
"log"
"net/http"
"os"
"time"
jwt "github.com/appleboy/gin-jwt/v2"
"github.com/gin-gonic/gin"
)
type login struct {
Username string `form:"username" json:"username" binding:"required"`
Password string `form:"password" json:"password" binding:"required"`
}
var (
identityKey = "id"
port string
)
// User demo
type User struct {
UserName string
FirstName string
LastName string
}
func init() {
port = os.Getenv("PORT")
if port == "" {
port = "8000"
}
}
func main() {
engine := gin.Default()
// the jwt middleware
authMiddleware, err := jwt.New(initParams())
if err != nil {
log.Fatal("JWT Error:" + err.Error())
}
// register middleware
engine.Use(handlerMiddleWare(authMiddleware))
// register route
registerRoute(engine, authMiddleware)
// start http server
if err = http.ListenAndServe(":"+port, engine); err != nil {
log.Fatal(err)
}
}
func registerRoute(r *gin.Engine, handle *jwt.GinJWTMiddleware) {
r.POST("/login", handle.LoginHandler)
r.NoRoute(handle.MiddlewareFunc(), handleNoRoute())
auth := r.Group("/auth", handle.MiddlewareFunc())
auth.GET("/refresh_token", handle.RefreshHandler)
auth.GET("/hello", helloHandler)
}
func handlerMiddleWare(authMiddleware *jwt.GinJWTMiddleware) gin.HandlerFunc {
return func(context *gin.Context) {
errInit := authMiddleware.MiddlewareInit()
if errInit != nil {
log.Fatal("authMiddleware.MiddlewareInit() Error:" + errInit.Error())
}
}
}
func initParams() *jwt.GinJWTMiddleware {
return &jwt.GinJWTMiddleware{
Realm: "test zone",
Key: []byte("secret key"),
Timeout: time.Hour,
MaxRefresh: time.Hour,
IdentityKey: identityKey,
PayloadFunc: payloadFunc(),
IdentityHandler: identityHandler(),
Authenticator: authenticator(),
Authorizator: authorizator(),
Unauthorized: unauthorized(),
TokenLookup: "header: Authorization, query: token, cookie: jwt",
// TokenLookup: "query:token",
// TokenLookup: "cookie:token",
TokenHeadName: "Bearer",
TimeFunc: time.Now,
}
}
func payloadFunc() func(data interface{}) jwt.MapClaims {
return func(data interface{}) jwt.MapClaims {
if v, ok := data.(*User); ok {
return jwt.MapClaims{
identityKey: v.UserName,
}
}
return jwt.MapClaims{}
}
}
func identityHandler() func(c *gin.Context) interface{} {
return func(c *gin.Context) interface{} {
claims := jwt.ExtractClaims(c)
return &User{
UserName: claims[identityKey].(string),
}
}
}
func authenticator() func(c *gin.Context) (interface{}, error) {
return func(c *gin.Context) (interface{}, error) {
var loginVals login
if err := c.ShouldBind(&loginVals); err != nil {
return "", jwt.ErrMissingLoginValues
}
userID := loginVals.Username
password := loginVals.Password
if (userID == "admin" && password == "admin") || (userID == "test" && password == "test") {
return &User{
UserName: userID,
LastName: "Bo-Yi",
FirstName: "Wu",
}, nil
}
return nil, jwt.ErrFailedAuthentication
}
}
func authorizator() func(data interface{}, c *gin.Context) bool {
return func(data interface{}, c *gin.Context) bool {
if v, ok := data.(*User); ok && v.UserName == "admin" {
return true
}
return false
}
}
func unauthorized() func(c *gin.Context, code int, message string) {
return func(c *gin.Context, code int, message string) {
c.JSON(code, gin.H{
"code": code,
"message": message,
})
}
}
func handleNoRoute() func(c *gin.Context) {
return func(c *gin.Context) {
claims := jwt.ExtractClaims(c)
log.Printf("NoRoute claims: %#v\n", claims)
c.JSON(404, gin.H{"code": "PAGE_NOT_FOUND", "message": "Page not found"})
}
}
func helloHandler(c *gin.Context) {
claims := jwt.ExtractClaims(c)
user, _ := c.Get(identityKey)
c.JSON(200, gin.H{
"userID": claims[identityKey],
"userName": user.(*User).UserName,
"text": "Hello World.",
})
}
Demo
Please run _example/basic/server.go file and listen 8000
port.
go run _example/basic/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.",
"userID": "admin"
}
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."
}
Cookie Token
Use these options for setting the JWT in a cookie. See the Mozilla documentation for more information on these options.
SendCookie: true,
SecureCookie: false, //non HTTPS dev environments
CookieHTTPOnly: true, // JS can't modify
CookieDomain: "localhost:8080",
CookieName: "token", // default jwt
TokenLookup: "cookie:token",
CookieSameSite: http.SameSiteDefaultMode, //SameSiteDefaultMode, SameSiteLaxMode, SameSiteStrictMode, SameSiteNoneMode
Login request flow (using the LoginHandler)
PROVIDED: LoginHandler
This is a provided function to be called on any login endpoint, which will trigger the flow described below.
REQUIRED: Authenticator
This function should verify the user credentials given the gin context (i.e. password matches hashed password for a given user email, and any other authentication logic). Then the authenticator should return a struct or map that contains the user data that will be embedded in the jwt token. This might be something like an account id, role, is_verified, etc. After having successfully authenticated, the data returned from the authenticator is passed in as a parameter into the PayloadFunc
, which is used to embed the user identifiers mentioned above into the jwt token. If an error is returned, the Unauthorized
function is used (explained below).
OPTIONAL: PayloadFunc
This function is called after having successfully authenticated (logged in). It should take whatever was returned from Authenticator
and convert it into MapClaims
(i.e. map[string]interface{}). A typical use case of this function is for when Authenticator
returns a struct which holds the user identifiers, and that struct needs to be converted into a map. MapClaims
should include one element that is [IdentityKey
(default is "identity"): some_user_identity]. The elements of MapClaims
returned in PayloadFunc
will be embedded within the jwt token (as token claims). When users pass in their token on subsequent requests, you can get these claims back by using ExtractClaims
.
OPTIONAL: LoginResponse
After having successfully authenticated with Authenticator
, created the jwt token using the identifiers from map returned from PayloadFunc
, and set it as a cookie if SendCookie
is enabled, this function is called. It is used to handle any post-login logic. This might look something like using the gin context to return a JSON of the token back to the user.
Subsequent requests on endpoints requiring jwt token (using MiddlewareFunc)
PROVIDED: MiddlewareFunc
This is gin middleware that should be used within any endpoints that require the jwt token to be present. This middleware will parse the request headers for the token if it exists, and check that the jwt token is valid (not expired, correct signature). Then it will call IdentityHandler
followed by Authorizator
. If Authorizator
passes and all of the previous token validity checks passed, the middleware will continue the request. If any of these checks fail, the Unauthorized
function is used (explained below).
OPTIONAL: IdentityHandler
The default of this function is likely sufficient for your needs. The purpose of this function is to fetch the user identity from claims embedded within the jwt token, and pass this identity value to Authorizator
. This function assumes [IdentityKey
: some_user_identity] is one of the attributes embedded within the claims of the jwt token (determined by PayloadFunc
).
OPTIONAL: Authorizator
Given the user identity value (data
parameter) and the gin context, this function should check if the user is authorized to be reaching this endpoint (on the endpoints where the MiddlewareFunc
applies). This function should likely use ExtractClaims
to check if the user has the sufficient permissions to reach this endpoint, as opposed to hitting the database on every request. This function should return true if the user is authorized to continue through with the request, or false if they are not authorized (where Unauthorized
will be called).
Logout Request flow (using LogoutHandler)
PROVIDED: LogoutHandler
This is a provided function to be called on any logout endpoint, which will clear any cookies if SendCookie
is set, and then call LogoutResponse
.
OPTIONAL: LogoutResponse
This should likely just return back to the user the http status code, if logout was successful or not.
Refresh Request flow (using RefreshHandler)
PROVIDED: RefreshHandler
:
This is a provided function to be called on any refresh token endpoint. If the token passed in is was issued within the MaxRefreshTime
time frame, then this handler will create/set a new token similar to the LoginHandler
, and pass this token into RefreshResponse
OPTIONAL: RefreshResponse
:
This should likely return a JSON of the token back to the user, similar to LoginResponse
Failures with logging in, bad tokens, or lacking privileges
OPTIONAL Unauthorized
:
On any error logging in, authorizing the user, or when there was no token or a invalid token passed in with the request, the following will happen. The gin context will be aborted depending on DisabledAbort
, then HTTPStatusMessageFunc
is called which by default converts the error into a string. Finally the Unauthorized
function will be called. This function should likely return a JSON containing the http error code and error message to the user.