Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\rest\EventSubscriber;
Chris@0: 
Chris@14: use Drupal\Core\Cache\CacheableMetadata;
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@14: use Drupal\serialization\Normalizer\CacheableNormalizerInterface;
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@14:    * forget to specify a response 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@14:     $acceptable_response_formats = $route->hasRequirement('_format') ? explode('|', $route->getRequirement('_format')) : [];
Chris@14:     $acceptable_request_formats = $route->hasRequirement('_content_type_format') ? explode('|', $route->getRequirement('_content_type_format')) : [];
Chris@14:     $acceptable_formats = $request->isMethodCacheable() ? $acceptable_response_formats : $acceptable_request_formats;
Chris@0: 
Chris@0:     $requested_format = $request->getRequestFormat();
Chris@0:     $content_type_format = $request->getContentType();
Chris@0: 
Chris@14:     // If an acceptable response format is requested, then use that. Otherwise,
Chris@14:     // including and particularly when the client forgot to specify a response
Chris@14:     // format, then use heuristics to select the format that is most likely
Chris@14:     // expected.
Chris@14:     if (in_array($requested_format, $acceptable_response_formats, TRUE)) {
Chris@0:       return $requested_format;
Chris@0:     }
Chris@14: 
Chris@0:     // If a request body is present, then use the format corresponding to the
Chris@0:     // request body's Content-Type for the response, if it's an acceptable
Chris@0:     // format for the request.
Chris@14:     if (!empty($request->getContent()) && in_array($content_type_format, $acceptable_request_formats, TRUE)) {
Chris@0:       return $content_type_format;
Chris@0:     }
Chris@14: 
Chris@0:     // Otherwise, use the first acceptable format.
Chris@14:     if (!empty($acceptable_formats)) {
Chris@0:       return $acceptable_formats[0];
Chris@0:     }
Chris@14: 
Chris@0:     // Sometimes, there are no acceptable formats, e.g. DELETE routes.
Chris@14:     return NULL;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Renders a resource response body.
Chris@0:    *
Chris@14:    * During serialization, encoders and normalizers are able to explicitly
Chris@14:    * bubble cacheability metadata via the 'cacheability' key-value pair in the
Chris@14:    * received context. This bubbled cacheability metadata will be applied to the
Chris@14:    * the response.
Chris@14:    *
Chris@14:    * In versions of Drupal prior to 8.5, implicit bubbling of cacheability
Chris@14:    * metadata was allowed because there was no explicit cacheability metadata
Chris@14:    * bubbling API. To maintain backwards compatibility, we continue to support
Chris@14:    * this, but support for this will be dropped in Drupal 9.0.0. This is
Chris@14:    * especially useful when interacting with APIs that implicitly invoke
Chris@14:    * rendering (for example: generating URLs): this allows those to "leak", and
Chris@14:    * we collect their bubbled cacheability metadata automatically in a render
Chris@14:    * 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@14:       $serialization_context = [
Chris@14:         'request' => $request,
Chris@14:         CacheableNormalizerInterface::SERIALIZATION_CONTEXT_CACHEABILITY => new CacheableMetadata(),
Chris@14:       ];
Chris@14: 
Chris@14:       // @deprecated In Drupal 8.5.0, will be removed before Drupal 9.0.0. Use
Chris@14:       // explicit cacheability metadata bubbling instead. (The wrapping call to
Chris@14:       // executeInRenderContext() will be removed before Drupal 9.0.0.)
Chris@0:       $context = new RenderContext();
Chris@0:       $output = $this->renderer
Chris@14:         ->executeInRenderContext($context, function () use ($serializer, $data, $format, $serialization_context) {
Chris@14:           return $serializer->serialize($data, $format, $serialization_context);
Chris@0:         });
Chris@14:       if ($response instanceof CacheableResponseInterface) {
Chris@14:         if (!$context->isEmpty()) {
Chris@14:           @trigger_error('Implicit cacheability metadata bubbling (onto the global render context) in normalizers is deprecated since Drupal 8.5.0 and will be removed in Drupal 9.0.0. Use the "cacheability" serialization context instead, for explicit cacheability metadata bubbling. See https://www.drupal.org/node/2918937', E_USER_DEPRECATED);
Chris@14:           $response->addCacheableDependency($context->pop());
Chris@14:         }
Chris@14:         $response->addCacheableDependency($serialization_context[CacheableNormalizerInterface::SERIALIZATION_CONTEXT_CACHEABILITY]);
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@18:     if ($response->getCharset()) {
Chris@18:       $final_response->setCharset($response->getCharset());
Chris@18:     }
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: }