A powerful and flexible JWT authentication middleware for the Gin web framework, built on top of jwt-go. Easily add login, token refresh, and authorization to your Gin applications.
- Gin JWT Middleware
- 🔒 Simple JWT authentication for Gin
- 🔁 Built-in login, refresh, and logout handlers
- 🛡️ Customizable authentication, authorization, and claims
- 🍪 Cookie and header token support
- 📝 Easy integration and clear API
Warning: JWT tokens with weak secrets (e.g., short or simple passwords) are vulnerable to brute-force attacks. Recommendation: Use strong, long secrets or
RS256tokens. See the jwt-cracker repository for more information.
export GO111MODULE=on
go get github.com/appleboy/gin-jwt/v2import "github.com/appleboy/gin-jwt/v2"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.",
})
}Run the example server:
go run _example/basic/server.goInstall httpie for easy API testing.
http -v --json POST localhost:8000/login username=admin password=admin
http -v -f GET localhost:8000/auth/refresh_token "Authorization:Bearer xxxxxxxxx" "Content-Type: application/json"
Login as admin/admin and call:
http -f GET localhost:8000/auth/hello "Authorization:Bearer xxxxxxxxx" "Content-Type: application/json"Response:
{
"text": "Hello World.",
"userID": "admin"
}Login as test/test and call:
http -f GET localhost:8000/auth/hello "Authorization:Bearer xxxxxxxxx" "Content-Type: application/json"Response:
{
"code": 403,
"message": "You don't have permission to access."
}To set the JWT in a cookie, use these options (see MDN docs):
SendCookie: true,
SecureCookie: false, // for 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, SameSiteNoneModePROVIDED: 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.
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).
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.
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
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.
