jwt

Gin JWT Middleware

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A powerful and flexible JWT authentication middleware for the Gin web framework, built on top of golang-jwt/jwt. Easily add login, token refresh, and authorization to your Gin applications.

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Table of Contents

• Gin JWT Middleware
  • Table of Contents
  • Features
  • Security Notice
    • 🔒 Critical Security Requirements
    • 🛡️ Production Security Checklist
    • 🔄 OAuth 2.0 Security Standards
    • 💡 Secure Configuration Example
  • Installation
  • Quick Start Example
  • Complete Examples
    • 🔑 Basic Authentication
    • 🌐 OAuth SSO Integration
    • 🔐 Token Generator
    • 🗄️ Redis Store
    • 🛡️ Authorization
  • Configuration
  • JWT Parsing Options
    • Clock Skew Tolerance (Leeway)
      • When to Use Leeway
      • Configuration Example
      • How Leeway Works
    • Other Parsing Options
      • JSON Number Handling
      • Required Claims Validation
      • Combining Multiple Options
  • Supporting Multiple JWT Providers
    • Use Cases
    • Solution: Dynamic Key Function
      • Why This Works
    • Implementation Strategy
      • Step 1: Create a Unified Middleware
      • Step 2: Helper Functions
      • Step 3: Route Setup
    • Complete Azure AD Integration Example
    • Alternative Approach: Custom Wrapper Middleware
    • Key Considerations
    • Testing Multi-Provider Setup
    • Common Issues and Solutions
    • Additional Resources
  • Token Generator (Direct Token Creation)
    • Basic Usage
    • Token Structure
    • Refresh Token Management
  • Redis Store Configuration
    • Redis Features
    • Redis Usage Methods
      • Using Functional Options Pattern (Recommended)
      • Available Options
    • Configuration Options
      • RedisConfig
    • Fallback Behavior
    • Example with Redis
  • Demo
    • Login
    • Refresh Token
    • Hello World
    • Authorization Example
  • Understanding the Authorizer
    • How Authorizer Works
    • Authorizer Function Signature
    • Basic Usage Examples
      • Example 1: Role-Based Authorization
      • Example 2: Path-Based Authorization
      • Example 3: Method and Path Based Authorization
    • Setting Up Different Authorization for Different Routes
      • Method 1: Multiple Middleware Instances
      • Method 2: Single Authorizer with Path Logic
    • Advanced Authorization Patterns
      • Using Claims for Fine-Grained Control
    • Common Patterns and Best Practices
    • Complete Example
    • Logout
  • Cookie Token
    • Refresh Token Cookie Support
    • Login request flow (using the LoginHandler)
    • Subsequent requests on endpoints requiring jwt token (using MiddlewareFunc)
    • Logout Request flow (using LogoutHandler)
    • Refresh Request flow (using RefreshHandler)
    • Failures with logging in, bad tokens, or lacking privileges

---

Features

• 🔒 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
• 🔐 RFC 6749 compliant refresh tokens (OAuth 2.0 standard)
• 🗄️ Pluggable refresh token storage (in-memory, Redis with client-side caching)
• 🏭 Direct token generation without HTTP middleware
• 📦 Structured Token type with metadata

---

Security Notice

🔒 Critical Security Requirements

⚠️ JWT Secret Security

• Minimum Requirements: Use secrets of at least 256 bits (32 bytes) in length
• Never use: Simple passwords, dictionary words, or predictable patterns
• Recommended: Generate cryptographically secure random secrets or use RS256 algorithm
• Storage: Store secrets in environment variables, never hardcode in source code
• Vulnerability: Weak secrets are vulnerable to brute-force attacks (jwt-cracker)

🛡️ Production Security Checklist

• ✅ HTTPS Only: Always use HTTPS in production environments
• ✅ Strong Secrets: Minimum 256-bit randomly generated secrets
• ✅ Token Expiry: Set appropriate timeout values (recommended: 15-60 minutes for access tokens)
• ✅ Secure Cookies: Enable SecureCookie, CookieHTTPOnly, and appropriate SameSite settings
• ✅ Environment Variables: Store sensitive configuration in environment variables
• ✅ Input Validation: Validate all authentication inputs thoroughly

🔄 OAuth 2.0 Security Standards

This library follows RFC 6749 OAuth 2.0 security standards:

• Separate Tokens: Uses distinct opaque refresh tokens (not JWT) for enhanced security
• Server-Side Storage: Refresh tokens are stored and validated server-side
• Token Rotation: Refresh tokens are automatically rotated on each use
• Improved Security: Prevents JWT refresh token vulnerabilities and replay attacks

💡 Secure Configuration Example

// ❌ BAD: Weak secret, insecure settings
authMiddleware := &jwt.GinJWTMiddleware{
    Key:         []byte("weak"),           // Too short!
    Timeout:     time.Hour * 24,          // Too long!
    SecureCookie: false,                  // Insecure in production!
}

// ✅ GOOD: Strong security configuration
authMiddleware := &jwt.GinJWTMiddleware{
    Key:            []byte(os.Getenv("JWT_SECRET")), // From environment
    Timeout:        time.Minute * 15,                // Short-lived access tokens
    MaxRefresh:     time.Hour * 24 * 7,             // 1 week refresh validity
    SecureCookie:   true,                           // HTTPS only
    CookieHTTPOnly: true,                           // Prevent XSS
    CookieSameSite: http.SameSiteStrictMode,        // CSRF protection
    SendCookie:     true,                           // Enable secure cookies
}

---

Installation

Requires Go 1.24+

go get -u github.com/appleboy/gin-jwt/v3

import "github.com/appleboy/gin-jwt/v3"

---

Quick Start 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/v3"
  "github.com/gin-gonic/gin"
  "github.com/golang-jwt/jwt/v5"
)

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())
  }

  // initialize middleware
  errInit := authMiddleware.MiddlewareInit()
  if errInit != nil {
    log.Fatal("authMiddleware.MiddlewareInit() Error:" + errInit.Error())
  }

  // 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) {
  // Public routes
  r.POST("/login", handle.LoginHandler)
  r.POST("/refresh", handle.RefreshHandler) // RFC 6749 compliant refresh endpoint

  r.NoRoute(handle.MiddlewareFunc(), handleNoRoute())

  // Protected routes
  auth := r.Group("/auth", handle.MiddlewareFunc())
  auth.GET("/hello", helloHandler)
  auth.POST("/logout", handle.LogoutHandler) // Logout with refresh token revocation
}

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(),
    Authorizer:      authorizer(),
    Unauthorized:    unauthorized(),
    LogoutResponse:  logoutResponse(),
    TokenLookup:     "header: Authorization, query: token, cookie: jwt",
    // TokenLookup: "query:token",
    // TokenLookup: "cookie:token",
    TokenHeadName: "Bearer",
    TimeFunc:      time.Now,
  }
}

func payloadFunc() func(data any) jwt.MapClaims {
  return func(data any) jwt.MapClaims {
    if v, ok := data.(*User); ok {
      return jwt.MapClaims{
        identityKey: v.UserName,
      }
    }
    return jwt.MapClaims{}
  }
}

func identityHandler() func(c *gin.Context) any {
  return func(c *gin.Context) any {
    claims := jwt.ExtractClaims(c)
    return &User{
      UserName: claims[identityKey].(string),
    }
  }
}

func authenticator() func(c *gin.Context) (any, error) {
  return func(c *gin.Context) (any, 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 authorizer() func(c *gin.Context, data any) bool {
  return func(c *gin.Context, data any) 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 logoutResponse() func(c *gin.Context) {
  return func(c *gin.Context) {
    // This demonstrates that claims are now accessible during logout
    claims := jwt.ExtractClaims(c)
    user, exists := c.Get(identityKey)

    response := gin.H{
      "code":    http.StatusOK,
      "message": "Successfully logged out",
    }

    // Show that we can access user information during logout
    if len(claims) > 0 {
      response["logged_out_user"] = claims[identityKey]
    }
    if exists {
      response["user_info"] = user.(*User).UserName
    }

    c.JSON(http.StatusOK, response)
  }
}

func handleNoRoute() func(c *gin.Context) {
  return func(c *gin.Context) {
    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.",
  })
}

---

Complete Examples

This repository provides several complete example implementations demonstrating different use cases:

🔑 Basic Authentication

The basic example showing fundamental JWT authentication with login, protected routes, and token validation.

🌐 OAuth SSO Integration

OAuth 2.0 Single Sign-On example supporting multiple identity providers (Google, GitHub):

• OAuth 2.0 Authorization Code Flow
• CSRF protection with state tokens
• Dual authentication support: httpOnly cookies + Authorization headers
• Secure token delivery for both browser and mobile apps
• Interactive demo page included

🔐 Token Generator

Direct token generation without HTTP middleware, perfect for:

• Programmatic authentication
• Service-to-service communication
• Testing authenticated endpoints
• Custom authentication flows

🗄️ Redis Store

Demonstrates Redis integration for refresh token storage with:

• Client-side caching for improved performance
• Automatic fallback to in-memory store
• Production-ready configuration examples

🛡️ Authorization

Advanced authorization patterns including:

• Role-based access control
• Path-based authorization
• Multiple middleware instances
• Fine-grained permission control

---

Configuration

The GinJWTMiddleware struct provides the following configuration options:

Option	Type	Required	Default	Description
Realm	string	No	"gin jwt"	Realm name to display to the user.
SigningAlgorithm	string	No	"HS256"	Signing algorithm (HS256, HS384, HS512, RS256, RS384, RS512).
Key	[]byte	Yes	-	Secret key used for signing.
Timeout	time.Duration	No	time.Hour	Duration that a jwt token is valid.
MaxRefresh	time.Duration	No	0	Duration that a refresh token is valid.
Authenticator	func(c *gin.Context) (any, error)	Yes	-	Callback to authenticate the user. Returns user data.
Authorizer	func(c *gin.Context, data any) bool	No	true	Callback to authorize the authenticated user.
PayloadFunc	func(data any) jwt.MapClaims	No	-	Callback to add additional payload data to the token.
Unauthorized	func(c *gin.Context, code int, message string)	No	-	Callback for unauthorized requests.
LoginResponse	func(c *gin.Context, token *core.Token)	No	-	Callback for successful login response.
LogoutResponse	func(c *gin.Context)	No	-	Callback for successful logout response.
RefreshResponse	func(c *gin.Context, token *core.Token)	No	-	Callback for successful refresh response.
IdentityHandler	func(*gin.Context) any	No	-	Callback to retrieve identity from claims.
IdentityKey	string	No	"identity"	Key used to store identity in claims.
TokenLookup	string	No	"header:Authorization"	Source to extract token from (header, query, cookie).
TokenHeadName	string	No	"Bearer"	Header name prefix.
TimeFunc	func() time.Time	No	time.Now	Function to provide current time.
PrivKeyFile	string	No	-	Path to private key file (for RS algorithms).
PubKeyFile	string	No	-	Path to public key file (for RS algorithms).
SendCookie	bool	No	false	Whether to send token as a cookie.
CookieMaxAge	time.Duration	No	Timeout	Duration that the cookie is valid.
SecureCookie	bool	No	false	Whether to use secure cookies for access token (HTTPS only). Refresh token cookies are always secure.
CookieHTTPOnly	bool	No	false	Whether to use HTTPOnly cookies.
CookieDomain	string	No	-	Domain for the cookie.
CookieName	string	No	"jwt"	Name of the cookie.
RefreshTokenCookieName	string	No	"refresh_token"	Name of the refresh token cookie.
CookieSameSite	http.SameSite	No	-	SameSite attribute for the cookie.
SendAuthorization	bool	No	false	Whether to return authorization header for every request.
DisabledAbort	bool	No	false	Disable abort() of context.
ParseOptions	[]jwt.ParserOption	No	-	Options for parsing the JWT.

---

JWT Parsing Options

The ParseOptions field allows you to customize JWT parsing behavior using options from the golang-jwt/jwt library. This is particularly useful for handling clock skew, custom validation rules, and numeric claim types.

Clock Skew Tolerance (Leeway)

When running distributed systems across multiple servers, clock synchronization issues can cause valid tokens to be rejected. The jwt.WithLeeway() option adds a time buffer for validating time-based claims (exp, nbf, iat), preventing authentication failures due to minor clock differences between services.

When to Use Leeway

• 🌐 Microservices Architecture: Services on different machines with slightly unsynchronized clocks
• ☁️ Cloud Deployments: Distributed systems across different availability zones or regions
• 🔄 Load Balanced Environments: Multiple backend servers with small time drift
• 🧪 Testing Environments: Development/staging systems with less strict time synchronization

Configuration Example

authMiddleware, err := jwt.New(&jwt.GinJWTMiddleware{
    Realm:      "your realm",
    Key:        []byte("your-secret-key"),
    Timeout:    time.Hour,
    MaxRefresh: time.Hour * 24,

    // Add 60 seconds leeway for clock skew tolerance
    ParseOptions: []jwt.ParserOption{
        jwt.WithLeeway(60 * time.Second),
    },

    Authenticator: func(c *gin.Context) (interface{}, error) {
        // your authentication logic
    },
    // ... other configuration
})

How Leeway Works

With a 60-second leeway configuration:

• Expired tokens: A token that expired 30 seconds ago will still be accepted
• Not-before tokens: A token with nbf 30 seconds in the future will be accepted
• Issued-at validation: Tokens with iat slightly in the future will be accepted

Security Note: Use reasonable leeway values (30-120 seconds). Excessive leeway reduces token security by extending validity beyond intended expiration times.

Other Parsing Options

JSON Number Handling

By default, JWT numeric claims are parsed as float64. Use jwt.WithJSONNumber() to preserve exact numeric values:

ParseOptions: []jwt.ParserOption{
    jwt.WithJSONNumber(),
}

This is useful when you need precise integer values or want to avoid floating-point precision issues.

Required Claims Validation

Enforce that certain claims must be present in the token:

ParseOptions: []jwt.ParserOption{
    jwt.WithExpirationRequired(),  // Require 'exp' claim
    jwt.WithIssuedAt(),            // Validate 'iat' claim if present
}

Combining Multiple Options

You can combine multiple parser options:

ParseOptions: []jwt.ParserOption{
    jwt.WithLeeway(60 * time.Second),  // 60s clock skew tolerance
    jwt.WithJSONNumber(),              // Preserve numeric precision
    jwt.WithExpirationRequired(),      // Require expiration claim
}

---

Supporting Multiple JWT Providers

In some scenarios, you may need to accept JWT tokens from multiple sources, such as your own authentication system and external identity providers like Azure AD, Auth0, or other OAuth 2.0 providers. This section explains how to implement multi-provider token validation using the KeyFunc callback.

Use Cases

• 🔐 Hybrid Authentication: Support both internal and external authentication
• 🌐 Third-Party Integration: Accept tokens from Azure AD, Google, Auth0, etc.
• 🔄 Migration Scenarios: Gradually migrate from one auth system to another
• 🏢 Enterprise SSO: Support enterprise Single Sign-On alongside regular auth

Solution: Dynamic Key Function

The recommended approach is to use a single middleware with a dynamic KeyFunc that determines the appropriate validation method based on token properties (such as the issuer claim).

Why This Works

The KeyFunc callback (line 41 in auth_jwt.go:41) is designed for exactly this purpose. It allows you to:

• Inspect the token before validation
• Choose the correct signing key/method dynamically
• Avoid the abort issue when chaining multiple middlewares

Implementation Strategy

Step 1: Create a Unified Middleware

package main

import (
    "errors"
    "fmt"
    "strings"
    "time"

    jwt "github.com/appleboy/gin-jwt/v3"
    "github.com/gin-gonic/gin"
    "github.com/golang-jwt/jwt/v5"
)

func createMultiProviderAuthMiddleware() (*jwt.GinJWTMiddleware, error) {
    // Your own JWT secret
    ownSecret := []byte("your-secret-key")

    // Azure AD public keys (fetched from JWKS endpoint)
    azurePublicKeys := getAzurePublicKeys()

    return jwt.New(&jwt.GinJWTMiddleware{
        Realm:       "multi-provider-api",
        Key:         ownSecret, // Default key (required but may not be used)
        IdentityKey: "sub",
        Timeout:     time.Hour,

        // Dynamic key function - the core of multi-provider support
        KeyFunc: func(token *jwt.Token) (interface{}, error) {
            // Extract claims to determine token source
            claims, ok := token.Claims.(jwt.MapClaims)
            if !ok {
                return nil, errors.New("invalid claims type")
            }

            // Check the issuer claim to identify the token source
            issuer, _ := claims["iss"].(string)

            // Route 1: Azure AD tokens
            if isAzureADIssuer(issuer) {
                // Validate algorithm
                if token.Method.Alg() != "RS256" {
                    return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
                }

                // Get key ID from token header
                keyID, ok := token.Header["kid"].(string)
                if !ok {
                    return nil, errors.New("missing key ID in Azure AD token header")
                }

                // Look up the public key
                if key, found := azurePublicKeys[keyID]; found {
                    return key, nil
                }
                return nil, fmt.Errorf("unknown Azure AD key ID: %s", keyID)
            }

            // Route 2: Your own tokens
            // Validate that the signing method matches your configuration
            if token.Method.Alg() != "HS256" {
                return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
            }

            return ownSecret, nil
        },

        // Handle different identity formats from different providers
        IdentityHandler: func(c *gin.Context) interface{} {
            claims := jwt.ExtractClaims(c)

            // Try standard "sub" claim (used by most OAuth providers)
            if sub, ok := claims["sub"].(string); ok {
                return sub
            }

            // Fallback to custom "identity" claim
            if identity, ok := claims["identity"].(string); ok {
                return identity
            }

            return nil
        },

        // Optional: Provider-specific authorization
        Authorizer: func(c *gin.Context, data interface{}) bool {
            claims := jwt.ExtractClaims(c)
            issuer, _ := claims["iss"].(string)

            // Azure AD specific authorization
            if isAzureADIssuer(issuer) {
                return authorizeAzureADUser(claims, c)
            }

            // Your own token authorization
            return authorizeOwnUser(claims, c)
        },

        // Optional: Custom error messages for different providers
        HTTPStatusMessageFunc: func(c *gin.Context, e error) string {
            if strings.Contains(e.Error(), "Azure AD") {
                return "Azure AD token validation failed: " + e.Error()
            }
            return e.Error()
        },
    })
}

Step 2: Helper Functions

// Check if issuer is from Azure AD
func isAzureADIssuer(issuer string) bool {
    // Azure AD issuers look like:
    // https://login.microsoftonline.com/{tenant}/v2.0
    // https://sts.windows.net/{tenant}/
    return strings.Contains(issuer, "login.microsoftonline.com") ||
           strings.Contains(issuer, "sts.windows.net")
}

// Fetch and cache Azure AD public keys from JWKS endpoint
func getAzurePublicKeys() map[string]interface{} {
    // Implementation: Fetch from Azure AD JWKS endpoint
    // https://login.microsoftonline.com/common/discovery/v2.0/keys
    // or tenant-specific: https://login.microsoftonline.com/{tenant}/discovery/v2.0/keys

    // Use a library like github.com/lestrrat-go/jwx/v2/jwk for JWKS parsing
    // Implement caching to avoid fetching on every request

    keys := make(map[string]interface{})

    // Example structure (you need to implement the actual fetching):
    // jwkSet, err := jwk.Fetch(context.Background(),
    //     "https://login.microsoftonline.com/common/discovery/v2.0/keys")
    // if err != nil {
    //     log.Printf("Failed to fetch Azure AD keys: %v", err)
    //     return keys
    // }
    //
    // for it := jwkSet.Iterate(context.Background()); it.Next(context.Background()); {
    //     pair := it.Pair()
    //     key := pair.Value.(jwk.Key)
    //
    //     var rawKey interface{}
    //     if err := key.Raw(&rawKey); err == nil {
    //         keys[key.KeyID()] = rawKey
    //     }
    // }

    return keys
}

// Azure AD specific authorization
func authorizeAzureADUser(claims jwt.MapClaims, c *gin.Context) bool {
    // Check Azure AD specific claims

    // Example: Check roles claim
    if roles, ok := claims["roles"].([]interface{}); ok {
        for _, role := range roles {
            if role.(string) == "Admin" || role.(string) == "User" {
                return true
            }
        }
    }

    // Example: Check groups claim
    if groups, ok := claims["groups"].([]interface{}); ok {
        allowedGroups := []string{"group-id-1", "group-id-2"}
        for _, group := range groups {
            for _, allowed := range allowedGroups {
                if group.(string) == allowed {
                    return true
                }
            }
        }
    }

    // Example: Check app roles
    if appRoles, ok := claims["app_role"].(string); ok {
        if appRoles == "User.Read" || appRoles == "Admin.All" {
            return true
        }
    }

    return false
}

// Your own token authorization
func authorizeOwnUser(claims jwt.MapClaims, c *gin.Context) bool {
    // Your custom authorization logic
    if role, ok := claims["role"].(string); ok {
        return role == "admin" || role == "user"
    }
    return true
}

Step 3: Route Setup

func main() {
    r := gin.Default()

    // Initialize multi-provider middleware
    authMiddleware, err := createMultiProviderAuthMiddleware()
    if err != nil {
        log.Fatal("JWT Error: " + err.Error())
    }

    if err := authMiddleware.MiddlewareInit(); err != nil {
        log.Fatal("Middleware Init Error: " + err.Error())
    }

    // Public routes
    r.POST("/login", authMiddleware.LoginHandler) // For your own auth
    r.POST("/refresh", authMiddleware.RefreshHandler)

    // Protected routes - accepts tokens from any configured provider
    auth := r.Group("/api")
    auth.Use(authMiddleware.MiddlewareFunc())
    {
        auth.GET("/profile", func(c *gin.Context) {
            claims := jwt.ExtractClaims(c)
            issuer := claims["iss"].(string)

            c.JSON(200, gin.H{
                "message": "Success",
                "user_id": claims["sub"],
                "issuer":  issuer,
                "source":  determineTokenSource(issuer),
            })
        })
    }

    r.Run(":8080")
}

func determineTokenSource(issuer string) string {
    if isAzureADIssuer(issuer) {
        return "Azure AD"
    }
    return "Internal"
}

Complete Azure AD Integration Example

For a production-ready Azure AD integration, you'll need to:

Fetch JWKS Keys Dynamically:

import (
    "context"
    "crypto/rsa"
    "sync"
    "time"

    "github.com/lestrrat-go/jwx/v2/jwk"
)

type AzureADKeyProvider struct {
    jwksURL    string
    keys       map[string]*rsa.PublicKey
    mutex      sync.RWMutex
    lastUpdate time.Time
}

func NewAzureADKeyProvider(tenantID string) *AzureADKeyProvider {
    provider := &AzureADKeyProvider{
        jwksURL: fmt.Sprintf(
            "https://login.microsoftonline.com/%s/discovery/v2.0/keys",
            tenantID,
        ),
        keys: make(map[string]*rsa.PublicKey),
    }

    // Initial fetch
    provider.RefreshKeys()

    // Refresh keys every hour
    go func() {
        ticker := time.NewTicker(1 * time.Hour)
        defer ticker.Stop()
        for range ticker.C {
            provider.RefreshKeys()
        }
    }()

    return provider
}

func (p *AzureADKeyProvider) RefreshKeys() error {
    ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    defer cancel()

    set, err := jwk.Fetch(ctx, p.jwksURL)
    if err != nil {
        return fmt.Errorf("failed to fetch JWKS: %w", err)
    }

    newKeys := make(map[string]*rsa.PublicKey)

    for it := set.Keys(ctx); it.Next(ctx); {
        key := it.Pair().Value.(jwk.Key)

        var rawKey interface{}
        if err := key.Raw(&rawKey); err != nil {
            continue
        }

        if rsaKey, ok := rawKey.(*rsa.PublicKey); ok {
            newKeys[key.KeyID()] = rsaKey
        }
    }

    p.mutex.Lock()
    p.keys = newKeys
    p.lastUpdate = time.Now()
    p.mutex.Unlock()

    return nil
}

func (p *AzureADKeyProvider) GetKey(keyID string) (*rsa.PublicKey, bool) {
    p.mutex.RLock()
    defer p.mutex.RUnlock()

    key, found := p.keys[keyID]
    return key, found
}

Validate Azure AD Specific Claims:

func validateAzureADClaims(claims jwt.MapClaims) error {
    // Validate issuer
    iss, ok := claims["iss"].(string)
    if !ok || !isAzureADIssuer(iss) {
        return errors.New("invalid Azure AD issuer")
    }

    // Validate audience (your application ID)
    aud, ok := claims["aud"].(string)
    if !ok || aud != "your-app-client-id" {
        return errors.New("invalid audience")
    }

    // Validate tenant (optional, for single-tenant apps)
    tid, ok := claims["tid"].(string)
    if !ok || tid != "your-tenant-id" {
        return errors.New("invalid tenant")
    }

    return nil
}

Alternative Approach: Custom Wrapper Middleware

If you need even more control or want to keep providers completely separate:

func MultiAuthMiddleware(
    ownAuth *jwt.GinJWTMiddleware,
    externalAuth *jwt.GinJWTMiddleware,
) gin.HandlerFunc {
    return func(c *gin.Context) {
        // Try own authentication first
        ownAuth.DisabledAbort = true
        ownAuth.MiddlewareFunc()(c)

        // Check if authentication succeeded
        if _, exists := c.Get("JWT_PAYLOAD"); exists {
            c.Next()
            return
        }

        // Clear errors and try external provider
        c.Errors = c.Errors[:0]

        externalAuth.DisabledAbort = true
        externalAuth.MiddlewareFunc()(c)

        if _, exists := c.Get("JWT_PAYLOAD"); exists {
            c.Next()
            return
        }

        // Both failed
        c.JSON(401, gin.H{
            "code":    401,
            "message": "Invalid or missing authentication token",
        })
        c.Abort()
    }
}

Key Considerations

1. Token Issuer Validation: Always validate the iss claim to ensure tokens are from trusted sources
2. Audience Validation: Verify the aud claim matches your application's client ID
3. Algorithm Validation: Ensure the signing algorithm matches expectations (HS256 for your tokens, RS256 for Azure AD)
4. Key Caching: Cache public keys from JWKS endpoints to reduce latency
5. Key Rotation: Implement automatic key refresh to handle provider key rotation
6. Error Handling: Provide clear error messages indicating which provider validation failed
7. Security: Never skip signature validation or disable security checks

Testing Multi-Provider Setup

# Test with your own token
curl -H "Authorization: Bearer YOUR_INTERNAL_TOKEN" \
     http://localhost:8080/api/profile

# Test with Azure AD token
curl -H "Authorization: Bearer AZURE_AD_TOKEN" \
     http://localhost:8080/api/profile

Common Issues and Solutions

Issue: "Chaining middlewares causes first failure to abort request"

• Solution: Use KeyFunc approach with a single middleware instance

Issue: "Azure AD public keys change periodically"

• Solution: Implement automatic JWKS refresh (shown in AzureADKeyProvider example)

Issue: "Different token formats from different providers"

• Solution: Normalize claims in IdentityHandler and handle provider-specific formats

Issue: "Authorization logic differs per provider"

• Solution: Check issuer in Authorizer and route to provider-specific logic

Additional Resources

• Azure AD Token Validation
• JWKS (JSON Web Key Sets)
• RFC 7517 - JSON Web Key (JWK)
• lestrrat-go/jwx Library for JWKS handling

---

Token Generator (Direct Token Creation)

The TokenGenerator functionality allows you to create JWT tokens directly without HTTP middleware, perfect for programmatic authentication, testing, and custom flows.

Basic Usage

package main

import (
    "context"
    "fmt"
    "log"
    "time"

    jwt "github.com/appleboy/gin-jwt/v3"
    gojwt "github.com/golang-jwt/jwt/v5"
)

func main() {
    // Initialize the middleware
    authMiddleware, err := jwt.New(&jwt.GinJWTMiddleware{
        Realm:      "example zone",
        Key:        []byte("secret key"),
        Timeout:    time.Hour,
        MaxRefresh: time.Hour * 24,
        PayloadFunc: func(data any) gojwt.MapClaims {
            return gojwt.MapClaims{
                "user_id": data,
            }
        },
    })
    if err != nil {
        log.Fatal("JWT Error:" + err.Error())
    }

    // Create context for token operations
    ctx := context.Background()

    // Generate a complete token pair (access + refresh tokens)
    userData := "user123"
    tokenPair, err := authMiddleware.TokenGenerator(ctx, userData)
    if err != nil {
        log.Fatal("Failed to generate token pair:", err)
    }

    fmt.Printf("Access Token: %s\n", tokenPair.AccessToken)
    fmt.Printf("Refresh Token: %s\n", tokenPair.RefreshToken)
    fmt.Printf("Expires In: %d seconds\n", tokenPair.ExpiresIn())
}

Token Structure

The TokenGenerator method returns a structured core.Token:

type Token struct {
    AccessToken  string `json:"access_token"`   // JWT access token
    TokenType    string `json:"token_type"`     // Always "Bearer"
    RefreshToken string `json:"refresh_token"`  // Opaque refresh token
    ExpiresAt    int64  `json:"expires_at"`     // Unix timestamp
    CreatedAt    int64  `json:"created_at"`     // Unix timestamp
}

// Helper method
func (t *Token) ExpiresIn() int64 // Returns seconds until expiry

Refresh Token Management

Use TokenGeneratorWithRevocation to refresh tokens and automatically revoke old ones:

// Refresh with automatic revocation of old token
newTokenPair, err := authMiddleware.TokenGeneratorWithRevocation(ctx, userData, oldRefreshToken)
if err != nil {
    log.Fatal("Failed to refresh token:", err)
}

// Old refresh token is now invalid
fmt.Printf("New Access Token: %s\n", newTokenPair.AccessToken)
fmt.Printf("New Refresh Token: %s\n", newTokenPair.RefreshToken)

Use Cases:

• 🔧 Programmatic Authentication: Service-to-service communication
• 🧪 Testing: Generate tokens for testing authenticated endpoints
• 📝 Registration Flow: Issue tokens immediately after user signup
• ⚙️ Background Jobs: Create tokens for automated processes
• 🎛️ Custom Auth Flows: Build custom authentication logic

See the complete example for more details.

---

Redis Store Configuration

This library supports Redis as a backend for refresh token storage, with built-in client-side caching for improved performance. Redis store provides better scalability and persistence compared to the default in-memory store.

Redis Features

• 🔄 Client-side Caching: Built-in Redis client-side caching for improved performance
• 🚀 Automatic Fallback: Falls back to in-memory store if Redis connection fails
• ⚙️ Easy Configuration: Simple methods to configure Redis store
• 🔧 Method Chaining: Fluent API for convenient configuration
• 📦 Factory Pattern: Support for both Redis and memory stores

Redis Usage Methods

Using Functional Options Pattern (Recommended)

The Redis configuration now uses a functional options pattern for cleaner and more flexible configuration:

// Method 1: Enable Redis with default configuration
middleware := &jwt.GinJWTMiddleware{
    // ... other configuration
}.EnableRedisStore()

// Method 2: Enable Redis with custom address
middleware := &jwt.GinJWTMiddleware{
    // ... other configuration
}.EnableRedisStore(
    jwt.WithRedisAddr("redis.example.com:6379"),
)

// Method 3: Enable Redis with authentication
middleware := &jwt.GinJWTMiddleware{
    // ... other configuration
}.EnableRedisStore(
    jwt.WithRedisAddr("redis.example.com:6379"),
    jwt.WithRedisAuth("password", 0),
)

// Method 4: Full configuration with all options
middleware := &jwt.GinJWTMiddleware{
    // ... other configuration
}.EnableRedisStore(
    jwt.WithRedisAddr("redis.example.com:6379"),
    jwt.WithRedisAuth("password", 1),
    jwt.WithRedisCache(128*1024*1024, time.Minute),     // 128MB cache, 1min TTL
    jwt.WithRedisPool(20, time.Hour, 2*time.Hour),      // Pool config
    jwt.WithRedisKeyPrefix("myapp:jwt:"),               // Key prefix
)

// Method 5: Enable Redis with TLS (for secure connections)
tlsConfig := &tls.Config{
    MinVersion: tls.VersionTLS12,
}
middleware := &jwt.GinJWTMiddleware{
    // ... other configuration
}.EnableRedisStore(
    jwt.WithRedisAddr("redis.example.com:6380"),        // TLS port
    jwt.WithRedisAuth("password", 0),
    jwt.WithRedisTLS(tlsConfig),                        // Enable TLS
)

Available Options

• WithRedisAddr(addr string) - Sets Redis server address
• WithRedisAuth(password string, db int) - Sets authentication and database
• WithRedisTLS(tlsConfig *tls.Config) - Sets TLS configuration for secure connections
• WithRedisCache(size int, ttl time.Duration) - Configures client-side cache
• WithRedisPool(poolSize int, maxIdleTime, maxLifetime time.Duration) - Configures connection pool
• WithRedisKeyPrefix(prefix string) - Sets key prefix for Redis keys

Configuration Options

RedisConfig

• Addr: Redis server address (default: "localhost:6379")
• Password: Redis password (default: "")
• DB: Redis database number (default: 0)
• TLSConfig: TLS configuration for secure connections (default: nil)
• CacheSize: Client-side cache size in bytes (default: 128MB)
• CacheTTL: Client-side cache TTL (default: 1 minute)
• KeyPrefix: Prefix for all Redis keys (default: "gin-jwt:")

Fallback Behavior

If Redis connection fails during initialization:

• The middleware logs an error message
• Automatically falls back to in-memory store
• Application continues to function normally

This ensures high availability and prevents application failures due to Redis connectivity issues.

Example with Redis

See the Redis example for a complete implementation.

package main

import (
    "log"
    "net/http"
    "time"

    jwt "github.com/appleboy/gin-jwt/v3"
    "github.com/gin-gonic/gin"
)

func main() {
    r := gin.Default()

    authMiddleware, err := jwt.New(&jwt.GinJWTMiddleware{
        Realm:       "example zone",
        Key:         []byte("secret key"),
        Timeout:     time.Hour,
        MaxRefresh:  time.Hour * 24,
        IdentityKey: "id",

        PayloadFunc: func(data any) jwt.MapClaims {
            if v, ok := data.(map[string]any); ok {
                return jwt.MapClaims{
                    "id": v["username"],
                }
            }
            return jwt.MapClaims{}
        },

        Authenticator: func(c *gin.Context) (any, error) {
            var loginVals struct {
                Username string `json:"username"`
                Password string `json:"password"`
            }

            if err := c.ShouldBind(&loginVals); err != nil {
                return "", jwt.ErrMissingLoginValues
            }

            if loginVals.Username == "admin" && loginVals.Password == "admin" {
                return map[string]any{
                    "username": loginVals.Username,
                }, nil
            }

            return nil, jwt.ErrFailedAuthentication
        },
    }).EnableRedisStore(                                            // Enable Redis with options
        jwt.WithRedisAddr("localhost:6379"),                       // Redis server address
        jwt.WithRedisCache(64*1024*1024, 30*time.Second),         // 64MB cache, 30s TTL
    )

    if err != nil {
        log.Fatal("JWT Error:" + err.Error())
    }

    errInit := authMiddleware.MiddlewareInit()
    if errInit != nil {
        log.Fatal("authMiddleware.MiddlewareInit() Error:" + errInit.Error())
    }

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

    auth := r.Group("/auth")
    auth.Use(authMiddleware.MiddlewareFunc())
    {
        auth.GET("/hello", func(c *gin.Context) {
            c.JSON(200, gin.H{
                "message": "Hello World.",
            })
        })
        auth.GET("/refresh_token", authMiddleware.RefreshHandler)
    }

    if err := http.ListenAndServe(":8000", r); err != nil {
        log.Fatal(err)
    }
}

---

Demo

Run the example server:

go run _example/basic/server.go

Install httpie for easy API testing.

Login

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

Refresh Token

Using RFC 6749 compliant refresh tokens (default behavior):

# First login to get refresh token
http -v --json POST localhost:8000/login username=admin password=admin

# Method 1: With cookies enabled (automatic - recommended for browsers)
# The refresh token cookie is automatically sent, no need to manually include it
http -v POST localhost:8000/refresh --session=./session.json

# Method 2: Send refresh token in JSON body
http -v --json POST localhost:8000/refresh refresh_token=your_refresh_token_here

# Method 3: Use refresh token from response via form data
http -v --form POST localhost:8000/refresh refresh_token=your_refresh_token_here

Security Note: When SendCookie is enabled, refresh tokens are automatically stored in httpOnly cookies. Browser-based applications can simply call the refresh endpoint without manually including the token - it's handled automatically by the cookie mechanism.

Important: Query parameters are NOT supported for refresh tokens as they expose tokens in server logs, proxy logs, browser history, and Referer headers. Use cookies (recommended), JSON body, or form data instead.

Hello World

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"
}

Authorization Example

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."
}

---

Understanding the Authorizer

The Authorizer function is a crucial component for implementing role-based access control in your application. It determines whether an authenticated user has permission to access specific protected routes.

How Authorizer Works

The Authorizer is called automatically during the JWT middleware processing for any route that uses MiddlewareFunc(). Here's the execution flow:

1. Token Validation: JWT middleware validates the token
2. Identity Extraction: IdentityHandler extracts user identity from token claims
3. Authorization Check: Authorizer determines if the user can access the resource
4. Route Access: If authorized, request proceeds; otherwise, Unauthorized is called

Authorizer Function Signature

func(c *gin.Context, data any) bool

• c *gin.Context: The Gin context containing request information
• data any: User identity data returned by IdentityHandler
• Returns bool: true for authorized access, false to deny access

Basic Usage Examples

Example 1: Role-Based Authorization

func authorizeHandler() func(c *gin.Context, data any) bool {
    return func(c *gin.Context, data any) bool {
        if v, ok := data.(*User); ok && v.UserName == "admin" {
            return true  // Only admin users can access
        }
        return false
    }
}

Example 2: Path-Based Authorization

func authorizeHandler() func(c *gin.Context, data any) bool {
    return func(c *gin.Context, data any) bool {
        user, ok := data.(*User)
        if !ok {
            return false
        }

        path := c.Request.URL.Path

        // Admin can access all routes
        if user.Role == "admin" {
            return true
        }

        // Regular users can only access /auth/profile and /auth/hello
        allowedPaths := []string{"/auth/profile", "/auth/hello"}
        for _, allowedPath := range allowedPaths {
            if path == allowedPath {
                return true
            }
        }

        return false
    }
}

Example 3: Method and Path Based Authorization

func authorizeHandler() func(c *gin.Context, data any) bool {
    return func(c *gin.Context, data any) bool {
        user, ok := data.(*User)
        if !ok {
            return false
        }

        path := c.Request.URL.Path
        method := c.Request.Method

        // Admins have full access
        if user.Role == "admin" {
            return true
        }

        // Users can only GET their own profile
        if path == "/auth/profile" && method == "GET" {
            return true
        }

        // Users cannot modify or delete resources
        if method == "POST" || method == "PUT" || method == "DELETE" {
            return false
        }

        return true // Allow other GET requests
    }
}

Setting Up Different Authorization for Different Routes

To implement different authorization rules for different route groups, you can create multiple middleware instances or use path checking within a single Authorizer:

Method 1: Multiple Middleware Instances

// Admin-only middleware
adminMiddleware, _ := jwt.New(&jwt.GinJWTMiddleware{
    // ... other config
    Authorizer: func(c *gin.Context, data any) bool {
        if user, ok := data.(*User); ok {
            return user.Role == "admin"
        }
        return false
    },
})

// Regular user middleware
userMiddleware, _ := jwt.New(&jwt.GinJWTMiddleware{
    // ... other config
    Authorizer: func(c *gin.Context, data any) bool {
        if user, ok := data.(*User); ok {
            return user.Role == "user" || user.Role == "admin"
        }
        return false
    },
})

// Route setup
adminRoutes := r.Group("/admin", adminMiddleware.MiddlewareFunc())
userRoutes := r.Group("/user", userMiddleware.MiddlewareFunc())

Method 2: Single Authorizer with Path Logic

func authorizeHandler() func(c *gin.Context, data any) bool {
    return func(c *gin.Context, data any) bool {
        user, ok := data.(*User)
        if !ok {
            return false
        }

        path := c.Request.URL.Path

        // Admin routes - only admins allowed
        if strings.HasPrefix(path, "/admin/") {
            return user.Role == "admin"
        }

        // User routes - users and admins allowed
        if strings.HasPrefix(path, "/user/") {
            return user.Role == "user" || user.Role == "admin"
        }

        // Public authenticated routes - all authenticated users
        return true
    }
}

Advanced Authorization Patterns

Using Claims for Fine-Grained Control

func authorizeHandler() func(c *gin.Context, data any) bool {
    return func(c *gin.Context, data any) bool {
        // Extract additional claims
        claims := jwt.ExtractClaims(c)

        // Get user permissions from claims
        permissions, ok := claims["permissions"].([]interface{})
        if !ok {
            return false
        }

        // Check if user has required permission for this route
        requiredPermission := getRequiredPermission(c.Request.URL.Path)

        for _, perm := range permissions {
            if perm.(string) == requiredPermission {
                return true
            }
        }

        return false
    }
}

func getRequiredPermission(path string) string {
    permissionMap := map[string]string{
        "/auth/users":    "read_users",
        "/auth/reports":  "read_reports",
        "/auth/settings": "admin",
    }
    return permissionMap[path]
}

Common Patterns and Best Practices

1. Always validate the data type: Check if the user data can be cast to your expected type
2. Use claims for additional context: Access JWT claims using jwt.ExtractClaims(c)
3. Consider the request context: Use c.Request.URL.Path, c.Request.Method, etc.
4. Fail securely: Return false by default and explicitly allow access
5. Log authorization failures: Add logging for debugging authorization issues

Complete Example

See the authorization example for a complete implementation showing different authorization scenarios.

Logout

Login first, then call the logout endpoint with the JWT token:

# First login to get the JWT token
http -v --json POST localhost:8000/login username=admin password=admin

# Use the returned JWT token to logout (replace xxxxxxxxx with actual token)
http -f POST localhost:8000/auth/logout "Authorization:Bearer xxxxxxxxx" "Content-Type: application/json"

Response:

{
  "code": 200,
  "logged_out_user": "admin",
  "message": "Successfully logged out",
  "user_info": "admin"
}

The logout response demonstrates that JWT claims are now accessible during logout through jwt.ExtractClaims(c), allowing developers to access user information for logging, auditing, or cleanup purposes.

---

Cookie Token

To set the JWT in a cookie, use these options (see MDN docs):

SendCookie:            true,
SecureCookie:          false, // for non-HTTPS dev environments (applies to access token cookie only)
CookieHTTPOnly:        true,  // JS can't modify
CookieDomain:          "localhost:8080",
CookieName:            "token", // default jwt
RefreshTokenCookieName: "refresh_token", // default refresh_token
TokenLookup:           "cookie:token",
CookieSameSite:        http.SameSiteDefaultMode, // SameSiteDefaultMode, SameSiteLaxMode, SameSiteStrictMode, SameSiteNoneMode

Refresh Token Cookie Support

When SendCookie is enabled, the middleware automatically stores both access and refresh tokens as httpOnly cookies:

• Access Token Cookie: Stored with the name specified in CookieName (default: "jwt")
• Refresh Token Cookie: Stored with the name specified in RefreshTokenCookieName (default: "refresh_token")

The refresh token cookie:

• Uses the RefreshTokenTimeout duration (default: 30 days)
• Is always set with httpOnly: true for security
• Is always set with secure: true (HTTPS only) regardless of the SecureCookie setting
• Is automatically sent with refresh requests
• Is cleared on logout

Automatic Token Extraction: The RefreshHandler automatically extracts refresh tokens from cookies, form data, query parameters, or JSON body, in that order. This means you don't need to manually include the refresh token when using cookie-based authentication - it's handled automatically.

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]any). 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.

Standard JWT Claims (RFC 7519): You can set standard JWT claims in PayloadFunc for better interoperability:

• sub (Subject) - The user identifier (e.g., user ID)
• iss (Issuer) - The issuer of the token (e.g., your app name)
• aud (Audience) - The intended audience (e.g., your API)
• nbf (Not Before) - Token is not valid before this time
• iat (Issued At) - When the token was issued
• jti (JWT ID) - Unique identifier for the token

Note: The exp (Expiration) and orig_iat claims are managed by the framework and cannot be overwritten.

PayloadFunc: func(data any) jwt.MapClaims {
    if user, ok := data.(*User); ok {
        return jwt.MapClaims{
            "sub":      user.ID,              // Standard: Subject (user ID)
            "iss":      "my-app",             // Standard: Issuer
            "aud":      "my-api",             // Standard: Audience
            "identity": user.UserName,        // Custom claim
            "role":     user.Role,            // Custom claim
        }
    }
    return jwt.MapClaims{}
}

OPTIONAL: LoginResponse

After having successfully authenticated with Authenticator, created the jwt token using the identifiers from map returned from PayloadFunc, and set cookies if SendCookie is enabled, this function is called.

When SendCookie is enabled, the middleware automatically sets two httpOnly cookies before calling this function:

• Access Token Cookie: Named according to CookieName (default: "jwt")
• Refresh Token Cookie: Named according to RefreshTokenCookieName (default: "refresh_token")

This function receives the complete token information (including access token, refresh token, expiry, etc.) as a structured core.Token object. This function is used to handle any post-login logic and return the token response to the user.

Signature: func(c *gin.Context, token *core.Token)

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 Authorizer. If Authorizer 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 Authorizer. This function assumes [IdentityKey: some_user_identity] is one of the attributes embedded within the claims of the jwt token (determined by PayloadFunc).

OPTIONAL: Authorizer

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. The handler performs the following actions:

1. Extracts JWT claims to make them available in LogoutResponse (for logging/auditing)
2. Attempts to revoke the refresh token from the server-side store if provided
3. Clears authentication cookies if SendCookie is enabled:
   • Access Token Cookie: Named according to CookieName
   • Refresh Token Cookie: Named according to RefreshTokenCookieName
4. Calls LogoutResponse to return the response

The logout handler tries to extract the refresh token from multiple sources (cookie, form, query, JSON body) to ensure it can be properly revoked.

OPTIONAL: LogoutResponse

This function is called after logout processing is complete. It should return the appropriate HTTP response to indicate logout success or failure. Since logout doesn't generate new tokens, this function only receives the gin context. You can access JWT claims and user identity via jwt.ExtractClaims(c) and c.Get(identityKey) for logging or auditing purposes.

Signature: func(c *gin.Context)

Refresh Request flow (using RefreshHandler)

PROVIDED: RefreshHandler:

This is a provided function to be called on any refresh token endpoint. The handler expects a refresh_token parameter (RFC 6749 compliant) from multiple sources and validates it against the server-side token store. The handler automatically extracts the refresh token from the following sources in order of priority:

1. Cookie (most common for browser-based apps): RefreshTokenCookieName cookie (default: "refresh_token")
2. POST Form: refresh_token form field
3. JSON Body: refresh_token field in request body

Security Note: Query parameters are NOT supported for refresh tokens to prevent token leakage through server logs, proxy logs, browser history, and Referer headers. Only secure delivery methods are supported.

If the refresh token is valid and not expired, the handler will:

• Create a new access token and refresh token
• Revoke the old refresh token (token rotation)
• Set both tokens as cookies (if SendCookie is enabled)
• Pass the new tokens into RefreshResponse

This follows OAuth 2.0 security best practices by rotating refresh tokens and supporting multiple secure delivery methods.

Cookie-Based Authentication: When using cookies (recommended for browser apps), the refresh token is automatically sent with the request, so you don't need to manually include it. Simply call the refresh endpoint and the middleware handles everything.

OPTIONAL: RefreshResponse:

This function is called after successfully refreshing tokens. It receives the complete new token information as a structured core.Token object and should return a JSON response containing the new access_token, token_type, expires_in, and refresh_token fields, following RFC 6749 token response format. Note that when using cookies, the tokens are already set as httpOnly cookies before this function is called.

Signature: func(c *gin.Context, token *core.Token)

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.

Note: When a 401 Unauthorized response is returned, the middleware automatically adds a WWW-Authenticate header with the Bearer authentication scheme, as defined in RFC 6750 (OAuth 2.0 Bearer Token Usage), RFC 7235 (HTTP Authentication), and the MDN documentation:

WWW-Authenticate: Bearer realm="<your-realm>"

This header informs HTTP clients that Bearer token authentication is required, ensuring compatibility with standard HTTP authentication mechanisms.