Auth middleware with JWT

backend/controllers/user/user.go

@@ -10,6 +10,8 @@ import (
 	"log"
 	"net/http"
 
+	JWT "github.com/golang-jwt/jwt"
+
 	res "backend/utils/responses"
 
 	"github.com/gin-gonic/gin"
@@ -133,3 +135,13 @@ func Login(c *gin.Context) {
 	// Return successful login
 	res.Success(c, gin.H{"message": "Successfully logged in"})
 }
+
+// Returns info from token middleware
+func TokenInfo(c *gin.Context) {
+	user := c.MustGet("user").(JWT.MapClaims)
+	res.Success(c, gin.H{
+		"id":    user["id"],
+		"name":  user["name"],
+		"email": user["email"],
+	})
+}

backend/middleware/middleware.go

@@ -0,0 +1,36 @@
+package middleware
+
+import (
+	"backend/utils/jwt"
+	res "backend/utils/responses"
+
+	"github.com/gin-gonic/gin"
+)
+
+func IsAuthenticated() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// Get token from cookie
+		token, err := c.Cookie("jwt-token")
+		if err != nil {
+			res.NeedsToLogin(c)
+			return
+		}
+
+		// Parse and check token
+		parsed, err := jwt.ParseJWT(token)
+		if err != nil {
+			// Fail the request
+			res.NeedsToLogin(c)
+			return
+		}
+
+		// Set user in context
+		c.Set("user", parsed)
+
+		// Execute next middleware/request
+		c.Next()
+	}
+}
+
+// TODO: Implement middleware for accessing your specific template
+// Check if template exists, and is user template (type shi)

backend/routes/routes.go

@@ -2,6 +2,7 @@ package routes
 
 import (
 	"backend/controllers/user"
+	"backend/middleware"
 
 	"github.com/gin-gonic/gin"
 )
@@ -13,5 +14,11 @@ func SetupRoutes() *gin.Engine {
 	r.POST("/register", user.Register)
 	r.POST("/login", user.Login)
 
+	// Authenticated routes middleware/group
+	auth := r.Group("/")
+	auth.Use(middleware.IsAuthenticated())
+
+	auth.GET("/info", user.TokenInfo) // Route to check if user is authenticated
+
 	return r
 }

backend/utils/jwt/jwt.go

@@ -3,6 +3,7 @@ package jwt
 import (
 	"backend/config"
 	"backend/models/user"
+	"fmt"
 	"time"
 
 	"github.com/golang-jwt/jwt"
@@ -28,3 +29,27 @@ func GenerateJWT(u *user.User) (string, error) {
 
 	return tokenString, nil
 }
+
+func ParseJWT(tokenString string) (jwt.MapClaims, error) {
+	mySigningKey := []byte(config.Env["JWT_SECRET"])
+
+	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, error) {
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
+		}
+
+		return mySigningKey, nil
+	})
+	// Check token parsing errors
+	if err != nil {
+		return nil, err
+	}
+
+	// If good values then return
+	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+		return claims, nil
+	}
+
+	// Return on invalid token
+	return nil, fmt.Errorf("invalid token")
+}

backend/utils/responses/responses.go

@@ -1,6 +1,8 @@
 package responses
 
 import (
+	"net/http"
+
 	"github.com/gin-gonic/gin"
 )
 
@@ -19,3 +21,11 @@ func Error(c *gin.Context, err string, code int) {
 		"error":   err,
 	})
 }
+
+func NeedsToLogin(c *gin.Context) {
+	c.JSON(http.StatusUnauthorized, gin.H{
+		"success":             false,
+		"error":               "Authentication required",
+		"needsAuthentication": true, // only appears in this error
+	})
+}