refactor API error handling and response structure

includes/api.php

@@ -4,17 +4,17 @@ if (!defined('ABSPATH')) exit;
 function kc_api_permission_check() {
     if (!is_user_logged_in()) {
         return new WP_Error(
-            'kc_api_auth_required',
-            'Authentifizierung erforderlich.',
-            ['status' => 401]
+            'rest_no_route',
+            'Es wurde keine Route gefunden, die mit der URL und der Request-Methode identisch ist.',
+            ['status' => 404]
         );
     }
 
     if (!current_user_can('manage_options')) {
         return new WP_Error(
-            'kc_api_forbidden',
-            'Keine Berechtigung für diese API.',
-            ['status' => 403]
+            'rest_no_route',
+            'Es wurde keine Route gefunden, die mit der URL und der Request-Methode identisch ist.',
+            ['status' => 404]
         );
     }
 
@@ -118,16 +118,34 @@ add_action('rest_api_init', function() {
     ]);
 });
 
-add_filter('rest_endpoints', function($endpoints) {
+add_filter('rest_index', function($response) {
     if (current_user_can('manage_options')) {
-        return $endpoints;
+        return $response;
     }
 
-    foreach ($endpoints as $route => $handlers) {
+    if (!($response instanceof WP_REST_Response)) {
+        return $response;
+    }
+
+    $data = $response->get_data();
+    if (!is_array($data)) {
+        return $response;
+    }
+
+    if (!empty($data['namespaces']) && is_array($data['namespaces'])) {
+        $data['namespaces'] = array_values(array_filter($data['namespaces'], function($ns) {
+            return $ns !== 'kc-internal/v1';
+        }));
+    }
+
+    if (!empty($data['routes']) && is_array($data['routes'])) {
+        foreach ($data['routes'] as $route => $route_config) {
             if (strpos($route, '/kc-internal/v1/') === 0) {
-            unset($endpoints[$route]);
+                unset($data['routes'][$route]);
+            }
         }
     }
 
-    return $endpoints;
+    $response->set_data($data);
+    return $response;
 });