function AnonymousUserResponseSubscriber::onRespond

Adds a cache tag if the 'user.permissions' cache context is present.

Parameters

\Symfony\Component\HttpKernel\Event\FilterResponseEvent $event: The event to process.

File

core/lib/Drupal/Core/EventSubscriber/AnonymousUserResponseSubscriber.php, line 40

Class

AnonymousUserResponseSubscriber

Response subscriber to handle finished responses for the anonymous user.

Namespace

Code

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);
    }
}