comparison core/modules/big_pipe/src/EventSubscriber/HtmlResponseBigPipeSubscriber.php @ 0:c75dbcec494b

Initial commit from drush-created site

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