annotate core/lib/Drupal/Core/EventSubscriber/HtmlResponsePlaceholderStrategySubscriber.php @ 19:fa3358dc1485 tip

Add ndrum files
author Chris Cannam
date Wed, 28 Aug 2019 13:14:47 +0100
parents 4c8ae668cc8c
children
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Chris@0 1 <?php
Chris@0 2
Chris@0 3 namespace Drupal\Core\EventSubscriber;
Chris@0 4
Chris@0 5 use Drupal\Core\Render\HtmlResponse;
Chris@0 6 use Drupal\Core\Render\Placeholder\PlaceholderStrategyInterface;
Chris@0 7 use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
Chris@0 8 use Symfony\Component\HttpKernel\KernelEvents;
Chris@0 9 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
Chris@0 10
Chris@0 11 /**
Chris@0 12 * HTML response subscriber to allow for different placeholder strategies.
Chris@0 13 *
Chris@0 14 * This allows core and contrib to coordinate how to render placeholders;
Chris@0 15 * e.g. an EsiRenderStrategy could replace the placeholders with ESI tags,
Chris@0 16 * while e.g. a BigPipeRenderStrategy could store the placeholders in a
Chris@0 17 * BigPipe service and render them after the main content has been sent to
Chris@0 18 * the client.
Chris@0 19 */
Chris@0 20 class HtmlResponsePlaceholderStrategySubscriber implements EventSubscriberInterface {
Chris@0 21
Chris@0 22 /**
Chris@0 23 * The placeholder strategy to use.
Chris@0 24 *
Chris@0 25 * @var \Drupal\Core\Render\Placeholder\PlaceholderStrategyInterface
Chris@0 26 */
Chris@0 27 protected $placeholderStrategy;
Chris@0 28
Chris@0 29 /**
Chris@0 30 * Constructs a HtmlResponsePlaceholderStrategySubscriber object.
Chris@0 31 *
Chris@0 32 * @param \Drupal\Core\Render\Placeholder\PlaceholderStrategyInterface $placeholder_strategy
Chris@0 33 * The placeholder strategy to use.
Chris@0 34 */
Chris@0 35 public function __construct(PlaceholderStrategyInterface $placeholder_strategy) {
Chris@0 36 $this->placeholderStrategy = $placeholder_strategy;
Chris@0 37 }
Chris@0 38
Chris@0 39 /**
Chris@0 40 * Processes placeholders for HTML responses.
Chris@0 41 *
Chris@0 42 * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
Chris@0 43 * The event to process.
Chris@0 44 */
Chris@0 45 public function onRespond(FilterResponseEvent $event) {
Chris@0 46 $response = $event->getResponse();
Chris@0 47 if (!$response instanceof HtmlResponse) {
Chris@0 48 return;
Chris@0 49 }
Chris@0 50
Chris@0 51 $attachments = $response->getAttachments();
Chris@0 52 if (empty($attachments['placeholders'])) {
Chris@0 53 return;
Chris@0 54 }
Chris@0 55
Chris@0 56 $attachments['placeholders'] = $this->placeholderStrategy->processPlaceholders($attachments['placeholders']);
Chris@0 57
Chris@0 58 $response->setAttachments($attachments);
Chris@0 59 }
Chris@0 60
Chris@0 61 /**
Chris@0 62 * {@inheritdoc}
Chris@0 63 */
Chris@0 64 public static function getSubscribedEvents() {
Chris@0 65 // Run shortly before HtmlResponseSubscriber.
Chris@0 66 $events[KernelEvents::RESPONSE][] = ['onRespond', 5];
Chris@0 67 return $events;
Chris@0 68 }
Chris@0 69
Chris@0 70 }