Implement CORS middleware with configurable allowed origins and update config structure

go_cloud/internal/middleware/middleware.go

@@ -21,22 +21,38 @@ var RequestID = middleware.RequestID
 var Logger = middleware.Logger
 var Recoverer = middleware.Recoverer
 
-// CORS middleware
-func CORS(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Access-Control-Allow-Origin", "*")
-		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
-		w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
-		w.Header().Set("Access-Control-Allow-Credentials", "true")
-		w.Header().Set("Access-Control-Max-Age", "3600")
+// CORS middleware - accepts allowedOrigins comma-separated string
+func CORS(allowedOrigins string) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			origin := r.Header.Get("Origin")
+			// Check if origin is allowed
+			if origin != "" {
+				// Simple check - in production you'd want to parse allowedOrigins properly
+				for _, allowed := range strings.Split(allowedOrigins, ",") {
+					if strings.TrimSpace(allowed) == origin {
+						w.Header().Set("Access-Control-Allow-Origin", origin)
+						w.Header().Set("Access-Control-Allow-Credentials", "true")
+						break
+					}
+				}
+			}
+			// Fallback to * if no credentials needed
+			if w.Header().Get("Access-Control-Allow-Origin") == "" {
+				w.Header().Set("Access-Control-Allow-Origin", "*")
+			}
+			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
+			w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
+			w.Header().Set("Access-Control-Max-Age", "3600")
 
-		if r.Method == http.MethodOptions {
-			w.WriteHeader(http.StatusOK)
-			return
-		}
+			if r.Method == http.MethodOptions {
+				w.WriteHeader(http.StatusOK)
+				return
+			}
 
-		next.ServeHTTP(w, r)
-	})
+			next.ServeHTTP(w, r)
+		})
+	}
 }
 
 // TODO: Implement rate limiter