Version 1

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

diff --git a/web/core/lib/Drupal/Core/EventSubscriber/AnonymousUserResponseSubscriber.php b/web/core/lib/Drupal/Core/EventSubscriber/AnonymousUserResponseSubscriber.php
new file mode 100644 (file)
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+++ b/web/core/lib/Drupal/Core/EventSubscriber/AnonymousUserResponseSubscriber.php
@@ -0,0 +1,82 @@
+<?php
+
+namespace Drupal\Core\EventSubscriber;
+
+use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Core\Cache\CacheableResponseInterface;
+use Drupal\Core\Session\AccountInterface;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * Response subscriber to handle finished responses for the anonymous user.
+ */
+class AnonymousUserResponseSubscriber implements EventSubscriberInterface {
+
+  /**
+   * The current user.
+   *
+   * @var \Drupal\Core\Session\AccountInterface
+   */
+  protected $currentUser;
+
+  /**
+   * Constructs an AnonymousUserResponseSubscriber object.
+   *
+   * @param \Drupal\Core\Session\AccountInterface $current_user
+   *   The current user.
+   */
+  public function __construct(AccountInterface $current_user) {
+    $this->currentUser = $current_user;
+  }
+
+  /**
+   * Adds a cache tag if the 'user.permissions' cache context is present.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
+   *   The event to process.
+   */
+  public function onRespond(FilterResponseEvent $event) {
+    if (!$event->isMasterRequest()) {
+      return;
+    }
+
+    if (!$this->currentUser->isAnonymous()) {
+      return;
+    }
+
+    $response = $event->getResponse();
+    if (!$response instanceof CacheableResponseInterface) {
+      return;
+    }
+
+    // The 'user.permissions' cache context ensures that if the permissions for
+    // a role are modified, users are not served stale render cache content.
+    // But, when entire responses are cached in reverse proxies, the value for
+    // the cache context is never calculated, causing the stale response to not
+    // be invalidated. Therefore, when varying by permissions and the current
+    // user is the anonymous user, also add the cache tag for the 'anonymous'
+    // role.
+    if (in_array('user.permissions', $response->getCacheableMetadata()->getCacheContexts())) {
+      $per_permissions_response_for_anon = new CacheableMetadata();
+      $per_permissions_response_for_anon->setCacheTags(['config:user.role.anonymous']);
+      $response->addCacheableDependency($per_permissions_response_for_anon);
+    }
+  }
+
+  /**
+   * Registers the methods in this class that should be listeners.
+   *
+   * @return array
+   *   An array of event listener definitions.
+   */
+  public static function getSubscribedEvents() {
+    // Priority 5, so that it runs before FinishResponseSubscriber, but after
+    // event subscribers that add the associated cacheability metadata (which
+    // have priority 10). This one is conditional, so must run after those.
+    $events[KernelEvents::RESPONSE][] = ['onRespond', 5];
+    return $events;
+  }
+
+}