Auth middleware with JWT

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
+	})
+}