Chris@18: <?php
Chris@18: 
Chris@18: namespace Drupal\jsonapi\EventSubscriber;
Chris@18: 
Chris@18: use Drupal\Core\Cache\CacheableResponse;
Chris@18: use Drupal\Core\Cache\CacheableResponseInterface;
Chris@18: use Drupal\jsonapi\Normalizer\Value\CacheableNormalization;
Chris@18: use Drupal\jsonapi\ResourceResponse;
Chris@18: use Symfony\Component\EventDispatcher\EventSubscriberInterface;
Chris@18: use Symfony\Component\HttpFoundation\Request;
Chris@18: use Symfony\Component\HttpFoundation\Response;
Chris@18: use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
Chris@18: use Symfony\Component\HttpKernel\KernelEvents;
Chris@18: use Symfony\Component\Serializer\SerializerInterface;
Chris@18: 
Chris@18: /**
Chris@18:  * Response subscriber that serializes and removes ResourceResponses' data.
Chris@18:  *
Chris@18:  * @internal JSON:API maintains no PHP API. The API is the HTTP API. This class
Chris@18:  *   may change at any time and could break any dependencies on it.
Chris@18:  *
Chris@18:  * @see https://www.drupal.org/project/jsonapi/issues/3032787
Chris@18:  * @see jsonapi.api.php
Chris@18:  *
Chris@18:  * This is 99% identical to:
Chris@18:  *
Chris@18:  * \Drupal\rest\EventSubscriber\ResourceResponseSubscriber
Chris@18:  *
Chris@18:  * but with a few differences:
Chris@18:  * 1. It has the @jsonapi.serializer service injected instead of @serializer
Chris@18:  * 2. It has the @current_route_match service no longer injected
Chris@18:  * 3. It hardcodes the format to 'api_json'
Chris@18:  * 4. It adds the CacheableNormalization object returned by JSON:API
Chris@18:  *    normalization to the response object.
Chris@18:  * 5. It flattens only to a cacheable response if the HTTP method is cacheable.
Chris@18:  *
Chris@18:  * @see \Drupal\rest\EventSubscriber\ResourceResponseSubscriber
Chris@18:  */
Chris@18: class ResourceResponseSubscriber implements EventSubscriberInterface {
Chris@18: 
Chris@18:   /**
Chris@18:    * The serializer.
Chris@18:    *
Chris@18:    * @var \Symfony\Component\Serializer\SerializerInterface
Chris@18:    */
Chris@18:   protected $serializer;
Chris@18: 
Chris@18:   /**
Chris@18:    * Constructs a ResourceResponseSubscriber object.
Chris@18:    *
Chris@18:    * @param \Symfony\Component\Serializer\SerializerInterface $serializer
Chris@18:    *   The serializer.
Chris@18:    */
Chris@18:   public function __construct(SerializerInterface $serializer) {
Chris@18:     $this->serializer = $serializer;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * {@inheritdoc}
Chris@18:    *
Chris@18:    * @see \Drupal\rest\EventSubscriber\ResourceResponseSubscriber::getSubscribedEvents()
Chris@18:    * @see \Drupal\dynamic_page_cache\EventSubscriber\DynamicPageCacheSubscriber
Chris@18:    */
Chris@18:   public static function getSubscribedEvents() {
Chris@18:     // Run before the dynamic page cache subscriber (priority 100), so that
Chris@18:     // Dynamic Page Cache can cache flattened responses.
Chris@18:     $events[KernelEvents::RESPONSE][] = ['onResponse', 128];
Chris@18:     return $events;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Serializes ResourceResponse responses' data, and removes that data.
Chris@18:    *
Chris@18:    * @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
Chris@18:    *   The event to process.
Chris@18:    */
Chris@18:   public function onResponse(FilterResponseEvent $event) {
Chris@18:     $response = $event->getResponse();
Chris@18:     if (!$response instanceof ResourceResponse) {
Chris@18:       return;
Chris@18:     }
Chris@18: 
Chris@18:     $request = $event->getRequest();
Chris@18:     $format = 'api_json';
Chris@18:     $this->renderResponseBody($request, $response, $this->serializer, $format);
Chris@18:     $event->setResponse($this->flattenResponse($response, $request));
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Renders a resource response body.
Chris@18:    *
Chris@18:    * Serialization can invoke rendering (e.g., generating URLs), but the
Chris@18:    * serialization API does not provide a mechanism to collect the
Chris@18:    * bubbleable metadata associated with that (e.g., language and other
Chris@18:    * contexts), so instead, allow those to "leak" and collect them here in
Chris@18:    * a render context.
Chris@18:    *
Chris@18:    * @param \Symfony\Component\HttpFoundation\Request $request
Chris@18:    *   The request object.
Chris@18:    * @param \Drupal\jsonapi\ResourceResponse $response
Chris@18:    *   The response from the JSON:API resource.
Chris@18:    * @param \Symfony\Component\Serializer\SerializerInterface $serializer
Chris@18:    *   The serializer to use.
Chris@18:    * @param string|null $format
Chris@18:    *   The response format, or NULL in case the response does not need a format,
Chris@18:    *   for example for the response to a DELETE request.
Chris@18:    *
Chris@18:    * @todo Add test coverage for language negotiation contexts in
Chris@18:    *   https://www.drupal.org/node/2135829.
Chris@18:    */
Chris@18:   protected function renderResponseBody(Request $request, ResourceResponse $response, SerializerInterface $serializer, $format) {
Chris@18:     $data = $response->getResponseData();
Chris@18: 
Chris@18:     // If there is data to send, serialize and set it as the response body.
Chris@18:     if ($data !== NULL) {
Chris@18:       // First normalize the data. Note that error responses do not need a
Chris@18:       // normalization context, since there are no entities to normalize.
Chris@18:       // @see \Drupal\jsonapi\EventSubscriber\DefaultExceptionSubscriber::isJsonApiExceptionEvent()
Chris@18:       $context = !$response->isSuccessful() ? [] : static::generateContext($request);
Chris@18:       $jsonapi_doc_object = $serializer->normalize($data, $format, $context);
Chris@18:       // Having just normalized the data, we can associate its cacheability with
Chris@18:       // the response object.
Chris@18:       assert($jsonapi_doc_object instanceof CacheableNormalization);
Chris@18:       $response->addCacheableDependency($jsonapi_doc_object);
Chris@18:       // Finally, encode the normalized data (JSON:API's encoder rasterizes it
Chris@18:       // automatically).
Chris@18:       $response->setContent($serializer->encode($jsonapi_doc_object->getNormalization(), $format));
Chris@18:       $response->headers->set('Content-Type', $request->getMimeType($format));
Chris@18:     }
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Generates a top-level JSON:API normalization context.
Chris@18:    *
Chris@18:    * @param \Symfony\Component\HttpFoundation\Request $request
Chris@18:    *   The request from which the context can be derived.
Chris@18:    *
Chris@18:    * @return array
Chris@18:    *   The generated context.
Chris@18:    */
Chris@18:   protected static function generateContext(Request $request) {
Chris@18:     // Build the expanded context.
Chris@18:     $context = [
Chris@18:       'account' => NULL,
Chris@18:       'sparse_fieldset' => NULL,
Chris@18:     ];
Chris@18:     if ($request->query->get('fields')) {
Chris@18:       $context['sparse_fieldset'] = array_map(function ($item) {
Chris@18:         return explode(',', $item);
Chris@18:       }, $request->query->get('fields'));
Chris@18:     }
Chris@18:     return $context;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Flattens a fully rendered resource response.
Chris@18:    *
Chris@18:    * Ensures that complex data structures in ResourceResponse::getResponseData()
Chris@18:    * are not serialized. Not doing this means that caching this response object
Chris@18:    * requires deserializing the PHP data when reading this response object from
Chris@18:    * cache, which can be very costly, and is unnecessary.
Chris@18:    *
Chris@18:    * @param \Drupal\jsonapi\ResourceResponse $response
Chris@18:    *   A fully rendered resource response.
Chris@18:    * @param \Symfony\Component\HttpFoundation\Request $request
Chris@18:    *   The request for which this response is generated.
Chris@18:    *
Chris@18:    * @return \Drupal\Core\Cache\CacheableResponse|\Symfony\Component\HttpFoundation\Response
Chris@18:    *   The flattened response.
Chris@18:    */
Chris@18:   protected static function flattenResponse(ResourceResponse $response, Request $request) {
Chris@18:     $final_response = ($response instanceof CacheableResponseInterface && $request->isMethodCacheable()) ? new CacheableResponse() : new Response();
Chris@18:     $final_response->setContent($response->getContent());
Chris@18:     $final_response->setStatusCode($response->getStatusCode());
Chris@18:     $final_response->setProtocolVersion($response->getProtocolVersion());
Chris@18:     if ($charset = $response->getCharset()) {
Chris@18:       $final_response->setCharset($charset);
Chris@18:     }
Chris@18:     $final_response->headers = clone $response->headers;
Chris@18:     if ($final_response instanceof CacheableResponseInterface) {
Chris@18:       $final_response->addCacheableDependency($response->getCacheableMetadata());
Chris@18:     }
Chris@18:     return $final_response;
Chris@18:   }
Chris@18: 
Chris@18: }