Chris@18: <?php
Chris@18: 
Chris@18: namespace Drupal\jsonapi\Revisions;
Chris@18: 
Chris@18: use Drupal\Core\Cache\CacheableMetadata;
Chris@18: use Drupal\Core\Entity\EntityInterface;
Chris@18: use Drupal\Core\Http\Exception\CacheableBadRequestHttpException;
Chris@18: use Drupal\Core\Http\Exception\CacheableHttpException;
Chris@18: use Drupal\Core\Routing\EnhancerInterface;
Chris@18: use Drupal\jsonapi\Routing\Routes;
Chris@18: use Symfony\Cmf\Component\Routing\RouteObjectInterface;
Chris@18: use Symfony\Component\HttpFoundation\Request;
Chris@18: use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;
Chris@18: 
Chris@18: /**
Chris@18:  * Loads an appropriate revision for the requested resource version.
Chris@18:  *
Chris@18:  * @internal JSON:API maintains no PHP API since its API is the HTTP API. This
Chris@18:  *   class may change at any time and this will 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: final class ResourceVersionRouteEnhancer implements EnhancerInterface {
Chris@18: 
Chris@18:   /**
Chris@18:    * The route default parameter name.
Chris@18:    *
Chris@18:    * @var string
Chris@18:    */
Chris@18:   const REVISION_ID_KEY = 'revision_id';
Chris@18: 
Chris@18:   /**
Chris@18:    * The query parameter for providing a version (revision) value.
Chris@18:    *
Chris@18:    * @var string
Chris@18:    */
Chris@18:   const RESOURCE_VERSION_QUERY_PARAMETER = 'resourceVersion';
Chris@18: 
Chris@18:   /**
Chris@18:    * A route parameter key which indicates that working copies were requested.
Chris@18:    *
Chris@18:    * @var string
Chris@18:    */
Chris@18:   const WORKING_COPIES_REQUESTED = 'working_copies_requested';
Chris@18: 
Chris@18:   /**
Chris@18:    * The cache context by which vary the loaded entity revision.
Chris@18:    *
Chris@18:    * @var string
Chris@18:    *
Chris@18:    * @todo When D8 requires PHP >=5.6, convert to expression using the RESOURCE_VERSION_QUERY_PARAMETER constant.
Chris@18:    */
Chris@18:   const CACHE_CONTEXT = 'url.query_args:resourceVersion';
Chris@18: 
Chris@18:   /**
Chris@18:    * Resource version validation regex.
Chris@18:    *
Chris@18:    * @var string
Chris@18:    *
Chris@18:    * @todo When D8 requires PHP >=5.6, convert to expression using the VersionNegotiator::SEPARATOR constant.
Chris@18:    */
Chris@18:   const VERSION_IDENTIFIER_VALIDATOR = '/^[a-z]+[a-z_]*[a-z]+:[a-zA-Z0-9\-]+(:[a-zA-Z0-9\-]+)*$/';
Chris@18: 
Chris@18:   /**
Chris@18:    * The revision ID negotiator.
Chris@18:    *
Chris@18:    * @var \Drupal\jsonapi\Revisions\VersionNegotiator
Chris@18:    */
Chris@18:   protected $versionNegotiator;
Chris@18: 
Chris@18:   /**
Chris@18:    * ResourceVersionRouteEnhancer constructor.
Chris@18:    *
Chris@18:    * @param \Drupal\jsonapi\Revisions\VersionNegotiator $version_negotiator_manager
Chris@18:    *   The version negotiator.
Chris@18:    */
Chris@18:   public function __construct(VersionNegotiator $version_negotiator_manager) {
Chris@18:     $this->versionNegotiator = $version_negotiator_manager;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * {@inheritdoc}
Chris@18:    */
Chris@18:   public function enhance(array $defaults, Request $request) {
Chris@18:     if (!Routes::isJsonApiRequest($defaults) || !($resource_type = Routes::getResourceTypeNameFromParameters($defaults))) {
Chris@18:       return $defaults;
Chris@18:     }
Chris@18: 
Chris@18:     $has_version_param = $request->query->has(static::RESOURCE_VERSION_QUERY_PARAMETER);
Chris@18: 
Chris@18:     // If the resource type is not versionable, then nothing needs to be
Chris@18:     // enhanced.
Chris@18:     if (!$resource_type->isVersionable()) {
Chris@18:       // If the query parameter was provided but the resource type is not
Chris@18:       // versionable, provide a helpful error.
Chris@18:       if ($has_version_param) {
Chris@18:         // Until Drupal core has a generic revision access API, it is only safe
Chris@18:         // to support the `node` and `media` entity types because they are the
Chris@18:         // only // entity types that have revision access checks for forward
Chris@18:         // revisions that are not the default and not the latest revision.
Chris@18:         $cacheability = (new CacheableMetadata())->addCacheContexts(['url.path', static::CACHE_CONTEXT]);
Chris@18:         /* Uncomment the next line and remove the following one when https://www.drupal.org/project/drupal/issues/3002352 lands in core. */
Chris@18:         /* throw new CacheableHttpException($cacheability, 501, 'Resource versioning is not yet supported for this resource type.'); */
Chris@18:         $message = 'JSON:API does not yet support resource versioning for this resource type.';
Chris@18:         $message .= ' For context, see https://www.drupal.org/project/jsonapi/issues/2992833#comment-12818258.';
Chris@18:         $message .= ' To contribute, see https://www.drupal.org/project/drupal/issues/2350939 and https://www.drupal.org/project/drupal/issues/2809177.';
Chris@18:         throw new CacheableHttpException($cacheability, 501, $message, NULL, []);
Chris@18:       }
Chris@18:       return $defaults;
Chris@18:     }
Chris@18: 
Chris@18:     // Since the resource type is versionable, responses must always vary by the
Chris@18:     // requested version, without regard for whether a version query parameter
Chris@18:     // was provided or not.
Chris@18:     if (isset($defaults['entity'])) {
Chris@18:       assert($defaults['entity'] instanceof EntityInterface);
Chris@18:       $defaults['entity']->addCacheContexts([static::CACHE_CONTEXT]);
Chris@18:     }
Chris@18: 
Chris@18:     // If no version was specified, nothing is left to enhance.
Chris@18:     if (!$has_version_param) {
Chris@18:       return $defaults;
Chris@18:     }
Chris@18: 
Chris@18:     // Provide a helpful error when a version is specified with an unsafe
Chris@18:     // method.
Chris@18:     if (!$request->isMethodCacheable()) {
Chris@18:       throw new BadRequestHttpException(sprintf('%s requests with a `%s` query parameter are not supported.', $request->getMethod(), static::RESOURCE_VERSION_QUERY_PARAMETER));
Chris@18:     }
Chris@18: 
Chris@18:     $resource_version_identifier = $request->query->get(static::RESOURCE_VERSION_QUERY_PARAMETER);
Chris@18: 
Chris@18:     if (!static::isValidVersionIdentifier($resource_version_identifier)) {
Chris@18:       $cacheability = (new CacheableMetadata())->addCacheContexts([static::CACHE_CONTEXT]);
Chris@18:       $message = sprintf('A resource version identifier was provided in an invalid format: `%s`', $resource_version_identifier);
Chris@18:       throw new CacheableBadRequestHttpException($cacheability, $message);
Chris@18:     }
Chris@18: 
Chris@18:     // Determine if the request is for a collection resource.
Chris@18:     if ($defaults[RouteObjectInterface::CONTROLLER_NAME] === Routes::CONTROLLER_SERVICE_NAME . ':getCollection') {
Chris@18:       $latest_version_identifier = 'rel' . VersionNegotiator::SEPARATOR . 'latest-version';
Chris@18:       $working_copy_identifier = 'rel' . VersionNegotiator::SEPARATOR . 'working-copy';
Chris@18:       // Until Drupal core has a revision access API that works on entity
Chris@18:       // queries, filtering is not permitted on non-default revisions.
Chris@18:       if ($request->query->has('filter') && $resource_version_identifier !== $latest_version_identifier) {
Chris@18:         $cache_contexts = [
Chris@18:           'url.path',
Chris@18:           static::CACHE_CONTEXT,
Chris@18:           'url.query_args:filter',
Chris@18:         ];
Chris@18:         $cacheability = (new CacheableMetadata())->addCacheContexts($cache_contexts);
Chris@18:         $message = 'JSON:API does not support filtering on revisions other than the latest version because a secure Drupal core API does not yet exist to do so.';
Chris@18:         throw new CacheableHttpException($cacheability, 501, $message, NULL, []);
Chris@18:       }
Chris@18:       // 'latest-version' and 'working-copy' are the only acceptable version
Chris@18:       // identifiers for a collection resource.
Chris@18:       if (!in_array($resource_version_identifier, [$latest_version_identifier, $working_copy_identifier])) {
Chris@18:         $cacheability = (new CacheableMetadata())->addCacheContexts(['url.path', static::CACHE_CONTEXT]);
Chris@18:         $message = sprintf('Collection resources only support the following resource version identifiers: %s', implode(', ', [
Chris@18:           $latest_version_identifier,
Chris@18:           $working_copy_identifier,
Chris@18:         ]));
Chris@18:         throw new CacheableBadRequestHttpException($cacheability, $message);
Chris@18:       }
Chris@18:       // Whether the collection to be loaded should include only working copies.
Chris@18:       $defaults[static::WORKING_COPIES_REQUESTED] = $resource_version_identifier === $working_copy_identifier;
Chris@18:       return $defaults;
Chris@18:     }
Chris@18: 
Chris@18:     /** @var \Drupal\Core\Entity\EntityInterface $entity */
Chris@18:     $entity = $defaults['entity'];
Chris@18: 
Chris@18:     /** @var \Drupal\jsonapi\Revisions\VersionNegotiatorInterface $negotiator */
Chris@18:     $resolved_revision = $this->versionNegotiator->getRevision($entity, $resource_version_identifier);
Chris@18:     // Ensure none of the original entity cacheability is lost, especially the
Chris@18:     // query argument's cache context.
Chris@18:     $resolved_revision->addCacheableDependency($entity);
Chris@18:     return ['entity' => $resolved_revision] + $defaults;
Chris@18:   }
Chris@18: 
Chris@18:   /**
Chris@18:    * Validates the user input.
Chris@18:    *
Chris@18:    * @param string $resource_version
Chris@18:    *   The requested resource version identifier.
Chris@18:    *
Chris@18:    * @return bool
Chris@18:    *   TRUE if the received resource version value is valid, FALSE otherwise.
Chris@18:    */
Chris@18:   protected static function isValidVersionIdentifier($resource_version) {
Chris@18:     return preg_match(static::VERSION_IDENTIFIER_VALIDATOR, $resource_version) === 1;
Chris@18:   }
Chris@18: 
Chris@18: }