add backend auth

backend/internal/auth/middleware.go

@@ -0,0 +1,41 @@
+package auth
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+const UserIDKey = "userID"
+
+func (s *AuthService) RequireAuth() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		header := c.GetHeader("Authorization")
+		if header == "" {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"error": gin.H{"code": "MISSING_TOKEN", "message": "authorization header required"},
+			})
+			return
+		}
+
+		parts := strings.SplitN(header, " ", 2)
+		if len(parts) != 2 || !strings.EqualFold(parts[0], "Bearer") {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"error": gin.H{"code": "INVALID_TOKEN", "message": "invalid authorization format"},
+			})
+			return
+		}
+
+		claims, err := s.ValidateAccessToken(parts[1])
+		if err != nil {
+			c.AbortWithStatusJSON(http.StatusUnauthorized, gin.H{
+				"error": gin.H{"code": "INVALID_TOKEN", "message": "invalid or expired token"},
+			})
+			return
+		}
+
+		c.Set(UserIDKey, claims)
+		c.Next()
+	}
+}