Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\big_pipe\EventSubscriber;
Chris@0: 
Chris@0: use Drupal\Core\Render\HtmlResponse;
Chris@0: use Drupal\big_pipe\Render\BigPipe;
Chris@0: use Drupal\big_pipe\Render\BigPipeResponse;
Chris@0: use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
Chris@0: use Symfony\Component\HttpKernel\KernelEvents;
Chris@0: use Symfony\Component\EventDispatcher\EventSubscriberInterface;
Chris@0: 
Chris@0: /**
Chris@0:  * Response subscriber to replace the HtmlResponse with a BigPipeResponse.
Chris@0:  *
Chris@0:  * @see \Drupal\big_pipe\Render\BigPipe
Chris@0:  *
Chris@0:  * @todo Refactor once https://www.drupal.org/node/2577631 lands.
Chris@0:  */
Chris@0: class HtmlResponseBigPipeSubscriber implements EventSubscriberInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The BigPipe service.
Chris@0:    *
Chris@0:    * @var \Drupal\big_pipe\Render\BigPipe
Chris@0:    */
Chris@0:   protected $bigPipe;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a HtmlResponseBigPipeSubscriber object.
Chris@0:    *
Chris@0:    * @param \Drupal\big_pipe\Render\BigPipe $big_pipe
Chris@0:    *   The BigPipe service.
Chris@0:    */
Chris@0:   public function __construct(BigPipe $big_pipe) {
Chris@0:     $this->bigPipe = $big_pipe;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Adds markers to the response necessary for the BigPipe render strategy.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
Chris@0:    *   The event to process.
Chris@0:    */
Chris@0:   public function onRespondEarly(FilterResponseEvent $event) {
Chris@0:     $response = $event->getResponse();
Chris@0:     if (!$response instanceof HtmlResponse) {
Chris@0:       return;
Chris@0:     }
Chris@0: 
Chris@0:     // Wrap the scripts_bottom placeholder with a marker before and after,
Chris@0:     // because \Drupal\big_pipe\Render\BigPipe needs to be able to extract that
Chris@0:     // markup if there are no-JS BigPipe placeholders.
Chris@0:     // @see \Drupal\big_pipe\Render\BigPipe::sendPreBody()
Chris@0:     $attachments = $response->getAttachments();
Chris@0:     if (isset($attachments['html_response_attachment_placeholders']['scripts_bottom'])) {
Chris@0:       $scripts_bottom_placeholder = $attachments['html_response_attachment_placeholders']['scripts_bottom'];
Chris@0:       $content = $response->getContent();
Chris@0:       $content = str_replace($scripts_bottom_placeholder, '<drupal-big-pipe-scripts-bottom-marker>' . $scripts_bottom_placeholder . '<drupal-big-pipe-scripts-bottom-marker>', $content);
Chris@0:       $response->setContent($content);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Transforms a HtmlResponse to a BigPipeResponse.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
Chris@0:    *   The event to process.
Chris@0:    */
Chris@0:   public function onRespond(FilterResponseEvent $event) {
Chris@0:     $response = $event->getResponse();
Chris@0:     if (!$response instanceof HtmlResponse) {
Chris@0:       return;
Chris@0:     }
Chris@0: 
Chris@0:     $attachments = $response->getAttachments();
Chris@0: 
Chris@0:     // If there are no no-JS BigPipe placeholders, unwrap the scripts_bottom
Chris@0:     // markup.
Chris@0:     // @see onRespondEarly()
Chris@0:     // @see \Drupal\big_pipe\Render\BigPipe::sendPreBody()
Chris@0:     if (empty($attachments['big_pipe_nojs_placeholders'])) {
Chris@0:       $content = $response->getContent();
Chris@0:       $content = str_replace('<drupal-big-pipe-scripts-bottom-marker>', '', $content);
Chris@0:       $response->setContent($content);
Chris@0:     }
Chris@0: 
Chris@0:     // If there are neither BigPipe placeholders nor no-JS BigPipe placeholders,
Chris@0:     // there isn't anything dynamic in this response, and we can return early:
Chris@0:     // there is no point in sending this response using BigPipe.
Chris@0:     if (empty($attachments['big_pipe_placeholders']) && empty($attachments['big_pipe_nojs_placeholders'])) {
Chris@0:       return;
Chris@0:     }
Chris@0: 
Chris@0:     $big_pipe_response = new BigPipeResponse($response);
Chris@0:     $big_pipe_response->setBigPipeService($this->getBigPipeService($event));
Chris@0:     $event->setResponse($big_pipe_response);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the BigPipe service to use to send the current response.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
Chris@0:    *   A response event.
Chris@0:    *
Chris@0:    * @return \Drupal\big_pipe\Render\BigPipe
Chris@0:    *   The BigPipe service.
Chris@0:    */
Chris@0:   protected function getBigPipeService(FilterResponseEvent $event) {
Chris@0:     return $this->bigPipe;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public static function getSubscribedEvents() {
Chris@0:     // Run after HtmlResponsePlaceholderStrategySubscriber (priority 5), i.e.
Chris@0:     // after BigPipeStrategy has been applied, but before normal (priority 0)
Chris@0:     // response subscribers have been applied, because by then it'll be too late
Chris@0:     // to transform it into a BigPipeResponse.
Chris@0:     $events[KernelEvents::RESPONSE][] = ['onRespondEarly', 3];
Chris@0: 
Chris@0:     // Run as the last possible subscriber.
Chris@0:     $events[KernelEvents::RESPONSE][] = ['onRespond', -10000];
Chris@0: 
Chris@0:     return $events;
Chris@0:   }
Chris@0: 
Chris@0: }