made edlp_ajax response cachable

sites/all/modules/figli/edlp_ajax/src/Controller/EdlpAjaxController.php

@@ -6,7 +6,10 @@ use Drupal\Core\Controller\ControllerBase;
 use Symfony\Component\HttpFoundation\Request;
 use Drupal\Core\Url;
 use Drupal\menu_link_content\Entity\MenuLinkContent;
-use Symfony\Component\HttpFoundation\JsonResponse;
+// use Symfony\Component\HttpFoundation\JsonResponse;
+use Drupal\Core\Cache\CacheableJsonResponse;
+use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\core\render\RenderContext;
 
 
 class EdlpAjaxController extends ControllerBase {
@@ -43,7 +46,12 @@ class EdlpAjaxController extends ControllerBase {
     $this->viewmode = $viewmode;
 
     $renderable = $this->toRenderable();
-    $rendered = render($renderable);
+    // $rendered = render($renderable);
+    // We can't render directly the entity as it throw an exception with cachable data
+    // see http://blog.dcycle.com/blog/2018-01-24/caching-drupal-8-rest-resource/#the-dreaded-leaked-metadata-error
+    $rendered = \Drupal::service('renderer')->executeInRenderContext(new RenderContext(), function () use ($renderable) {
+      return render($renderable);
+    });
 
     switch($this->entity_type){
       case 'node':
@@ -57,7 +65,7 @@ class EdlpAjaxController extends ControllerBase {
     }
 
     $data = [
-      'test' => 'hello edlp ajax',
+      'date' => time(),
       'id' => $this->id,
       'view_mode' => $this->viewmode,
       'bundle' => $bundle,
@@ -83,16 +91,30 @@ class EdlpAjaxController extends ControllerBase {
           $menu_parents[] = $sys_path;
         }
       }
-      $data['menu_parents'] = $menu_parents;
+      // $data['menu_parents'] = $menu_parents;
     }
 
-    $response = new JsonResponse();
-    $response->setData($data);
+    $data['#cache'] = [
+      'max-age' => \Drupal\Core\Cache\Cache::PERMANENT,
+      'tags' => [
+        'edlp-ajax-cache',
+        // $this->entity_type.':'.$this->id // not necessary as we add $renderable as CacheableMetadata to the response
+      ]
+    ];
+
+    // $response = new JsonResponse();
+    // $response->setData($data);
+    $response = new CacheableJsonResponse($data);
+    $response->addCacheableDependency(CacheableMetadata::createFromRenderArray($renderable));
+    $response->addCacheableDependency(CacheableMetadata::createFromRenderArray($data));
+
     return $response;
 
-    // return array(
-    //   '#markup'=>'hello'
-    // );
+    dpm($response);
+
+    return array(
+      '#markup'=>'hello'
+    );
   }
 
 }