Version 1

[yaffs-website] / web / core / lib / Drupal / Core / EventSubscriber / ClientErrorResponseSubscriber.php

diff --git a/web/core/lib/Drupal/Core/EventSubscriber/ClientErrorResponseSubscriber.php b/web/core/lib/Drupal/Core/EventSubscriber/ClientErrorResponseSubscriber.php
new file mode 100644 (file)
index 0000000..f93fc63
--- /dev/null
+++ b/web/core/lib/Drupal/Core/EventSubscriber/ClientErrorResponseSubscriber.php
@@ -0,0 +1,49 @@
+<?php
+
+namespace Drupal\Core\EventSubscriber;
+
+use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Core\Cache\CacheableResponseInterface;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Response subscriber to set the '4xx-response' cache tag on 4xx responses.
+ */
+class ClientErrorResponseSubscriber implements EventSubscriberInterface {
+
+  /**
+   * Sets the '4xx-response' cache tag on 4xx responses.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
+   *   The event to process.
+   */
+  public function onRespond(FilterResponseEvent $event) {
+    if (!$event->isMasterRequest()) {
+      return;
+    }
+
+    $response = $event->getResponse();
+    if (!$response instanceof CacheableResponseInterface) {
+      return;
+    }
+
+    if ($response->isClientError()) {
+      $http_4xx_response_cacheability = new CacheableMetadata();
+      $http_4xx_response_cacheability->setCacheTags(['4xx-response']);
+      $response->addCacheableDependency($http_4xx_response_cacheability);
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    // Priority 10, so that it runs before FinishResponseSubscriber, which will
+    // expose the cacheability metadata in the form of headers.
+    $events[KernelEvents::RESPONSE][] = ['onRespond', 10];
+    return $events;
+  }
+
+}