Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\rest\EventSubscriber;
Chris@0: 
Chris@0: use Drupal\Core\Cache\CacheableResponse;
Chris@0: use Drupal\Core\Cache\CacheableResponseInterface;
Chris@0: use Drupal\Core\Render\RenderContext;
Chris@0: use Drupal\Core\Render\RendererInterface;
Chris@0: use Drupal\Core\Routing\RouteMatchInterface;
Chris@0: use Drupal\rest\ResourceResponseInterface;
Chris@0: use Symfony\Component\HttpFoundation\Request;
Chris@0: use Symfony\Component\HttpFoundation\Response;
Chris@0: use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
Chris@0: use Symfony\Component\HttpKernel\KernelEvents;
Chris@0: use Symfony\Component\EventDispatcher\EventSubscriberInterface;
Chris@0: use Symfony\Component\Serializer\SerializerInterface;
Chris@0: 
Chris@0: /**
Chris@0:  * Response subscriber that serializes and removes ResourceResponses' data.
Chris@0:  */
Chris@0: class ResourceResponseSubscriber implements EventSubscriberInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The serializer.
Chris@0:    *
Chris@0:    * @var \Symfony\Component\Serializer\SerializerInterface
Chris@0:    */
Chris@0:   protected $serializer;
Chris@0: 
Chris@0:   /**
Chris@0:    * The renderer.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Render\RendererInterface
Chris@0:    */
Chris@0:   protected $renderer;
Chris@0: 
Chris@0:   /**
Chris@0:    * The current route match.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Routing\RouteMatchInterface
Chris@0:    */
Chris@0:   protected $routeMatch;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a ResourceResponseSubscriber object.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\Serializer\SerializerInterface $serializer
Chris@0:    *   The serializer.
Chris@0:    * @param \Drupal\Core\Render\RendererInterface $renderer
Chris@0:    *   The renderer.
Chris@0:    * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
Chris@0:    *   The current route match.
Chris@0:    */
Chris@0:   public function __construct(SerializerInterface $serializer, RendererInterface $renderer, RouteMatchInterface $route_match) {
Chris@0:     $this->serializer = $serializer;
Chris@0:     $this->renderer = $renderer;
Chris@0:     $this->routeMatch = $route_match;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Serializes ResourceResponse responses' data, and removes that data.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
Chris@0:    *   The event to process.
Chris@0:    */
Chris@0:   public function onResponse(FilterResponseEvent $event) {
Chris@0:     $response = $event->getResponse();
Chris@0:     if (!$response instanceof ResourceResponseInterface) {
Chris@0:       return;
Chris@0:     }
Chris@0: 
Chris@0:     $request = $event->getRequest();
Chris@0:     $format = $this->getResponseFormat($this->routeMatch, $request);
Chris@0:     $this->renderResponseBody($request, $response, $this->serializer, $format);
Chris@0:     $event->setResponse($this->flattenResponse($response));
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Determines the format to respond in.
Chris@0:    *
Chris@0:    * Respects the requested format if one is specified. However, it is common to
Chris@0:    * forget to specify a request format in case of a POST or PATCH. Rather than
Chris@0:    * simply throwing an error, we apply the robustness principle: when POSTing
Chris@0:    * or PATCHing using a certain format, you probably expect a response in that
Chris@0:    * same format.
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
Chris@0:    *   The current route match.
Chris@0:    * @param \Symfony\Component\HttpFoundation\Request $request
Chris@0:    *   The current request.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   The response format.
Chris@0:    */
Chris@0:   public function getResponseFormat(RouteMatchInterface $route_match, Request $request) {
Chris@0:     $route = $route_match->getRouteObject();
Chris@0:     $acceptable_request_formats = $route->hasRequirement('_format') ? explode('|', $route->getRequirement('_format')) : [];
Chris@0:     $acceptable_content_type_formats = $route->hasRequirement('_content_type_format') ? explode('|', $route->getRequirement('_content_type_format')) : [];
Chris@0:     $acceptable_formats = $request->isMethodCacheable() ? $acceptable_request_formats : $acceptable_content_type_formats;
Chris@0: 
Chris@0:     $requested_format = $request->getRequestFormat();
Chris@0:     $content_type_format = $request->getContentType();
Chris@0: 
Chris@0:     // If an acceptable format is requested, then use that. Otherwise, including
Chris@0:     // and particularly when the client forgot to specify a format, then use
Chris@0:     // heuristics to select the format that is most likely expected.
Chris@0:     if (in_array($requested_format, $acceptable_formats)) {
Chris@0:       return $requested_format;
Chris@0:     }
Chris@0:     // If a request body is present, then use the format corresponding to the
Chris@0:     // request body's Content-Type for the response, if it's an acceptable
Chris@0:     // format for the request.
Chris@0:     elseif (!empty($request->getContent()) && in_array($content_type_format, $acceptable_content_type_formats)) {
Chris@0:       return $content_type_format;
Chris@0:     }
Chris@0:     // Otherwise, use the first acceptable format.
Chris@0:     elseif (!empty($acceptable_formats)) {
Chris@0:       return $acceptable_formats[0];
Chris@0:     }
Chris@0:     // Sometimes, there are no acceptable formats, e.g. DELETE routes.
Chris@0:     else {
Chris@0:       return NULL;
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Renders a resource response body.
Chris@0:    *
Chris@0:    * Serialization can invoke rendering (e.g., generating URLs), but the
Chris@0:    * serialization API does not provide a mechanism to collect the
Chris@0:    * bubbleable metadata associated with that (e.g., language and other
Chris@0:    * contexts), so instead, allow those to "leak" and collect them here in
Chris@0:    * a render context.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\HttpFoundation\Request $request
Chris@0:    *   The request object.
Chris@0:    * @param \Drupal\rest\ResourceResponseInterface $response
Chris@0:    *   The response from the REST resource.
Chris@0:    * @param \Symfony\Component\Serializer\SerializerInterface $serializer
Chris@0:    *   The serializer to use.
Chris@0:    * @param string|null $format
Chris@0:    *   The response format, or NULL in case the response does not need a format,
Chris@0:    *   for example for the response to a DELETE request.
Chris@0:    *
Chris@0:    * @todo Add test coverage for language negotiation contexts in
Chris@0:    *   https://www.drupal.org/node/2135829.
Chris@0:    */
Chris@0:   protected function renderResponseBody(Request $request, ResourceResponseInterface $response, SerializerInterface $serializer, $format) {
Chris@0:     $data = $response->getResponseData();
Chris@0: 
Chris@0:     // If there is data to send, serialize and set it as the response body.
Chris@0:     if ($data !== NULL) {
Chris@0:       $context = new RenderContext();
Chris@0:       $output = $this->renderer
Chris@0:         ->executeInRenderContext($context, function () use ($serializer, $data, $format) {
Chris@0:           return $serializer->serialize($data, $format);
Chris@0:         });
Chris@0: 
Chris@0:       if ($response instanceof CacheableResponseInterface && !$context->isEmpty()) {
Chris@0:         $response->addCacheableDependency($context->pop());
Chris@0:       }
Chris@0: 
Chris@0:       $response->setContent($output);
Chris@0:       $response->headers->set('Content-Type', $request->getMimeType($format));
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Flattens a fully rendered resource response.
Chris@0:    *
Chris@0:    * Ensures that complex data structures in ResourceResponse::getResponseData()
Chris@0:    * are not serialized. Not doing this means that caching this response object
Chris@0:    * requires unserializing the PHP data when reading this response object from
Chris@0:    * cache, which can be very costly, and is unnecessary.
Chris@0:    *
Chris@0:    * @param \Drupal\rest\ResourceResponseInterface $response
Chris@0:    *   A fully rendered resource response.
Chris@0:    *
Chris@0:    * @return \Drupal\Core\Cache\CacheableResponse|\Symfony\Component\HttpFoundation\Response
Chris@0:    *   The flattened response.
Chris@0:    */
Chris@0:   protected function flattenResponse(ResourceResponseInterface $response) {
Chris@0:     $final_response = ($response instanceof CacheableResponseInterface) ? new CacheableResponse() : new Response();
Chris@0:     $final_response->setContent($response->getContent());
Chris@0:     $final_response->setStatusCode($response->getStatusCode());
Chris@0:     $final_response->setProtocolVersion($response->getProtocolVersion());
Chris@0:     $final_response->setCharset($response->getCharset());
Chris@0:     $final_response->headers = clone $response->headers;
Chris@0:     if ($final_response instanceof CacheableResponseInterface) {
Chris@0:       $final_response->addCacheableDependency($response->getCacheableMetadata());
Chris@0:     }
Chris@0:     return $final_response;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public static function getSubscribedEvents() {
Chris@0:     // Run before \Drupal\dynamic_page_cache\EventSubscriber\DynamicPageCacheSubscriber
Chris@0:     // (priority 100), so that Dynamic Page Cache can cache flattened responses.
Chris@0:     $events[KernelEvents::RESPONSE][] = ['onResponse', 128];
Chris@0:     return $events;
Chris@0:   }
Chris@0: 
Chris@0: }