EntityRevisionParamConverter.php

<?php

namespace Drupal\Core\ParamConverter;

use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\EntityRepositoryInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Entity\TranslatableInterface;
use Symfony\Component\Routing\Route;

/**
 * Parameter converter for upcasting entity revision IDs to full objects.
 *
 * This is useful for pages which want to show a specific revision, like
 * "/entity_example/{entity_example}/revision/{entity_example_revision}".
 *
 *
 * In order to use it you should specify some additional options in your route:
 * @code
 * example.route:
 *   path: /foo/{entity_example_revision}
 *   options:
 *     parameters:
 *       entity_example_revision:
 *         type: entity_revision:entity_example
 * @endcode
 */
class EntityRevisionParamConverter implements ParamConverterInterface {
    use DynamicEntityTypeParamConverterTrait;
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * The entity repository.
     *
     * @var \Drupal\Core\Entity\EntityRepositoryInterface
     */
    protected $entityRepository;
    
    /**
     * Creates a new EntityRevisionParamConverter instance.
     *
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager.
     * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
     *   The entity repository.
     */
    public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityRepositoryInterface $entity_repository) {
        $this->entityTypeManager = $entity_type_manager;
        $this->entityRepository = $entity_repository;
    }
    
    /**
     * {@inheritdoc}
     */
    public function convert($value, $definition, $name, array $defaults) {
        $entity_type_id = $this->getEntityTypeFromDefaults($definition, $name, $defaults);
        $entity = $this->entityTypeManager
            ->getStorage($entity_type_id)
            ->loadRevision($value);
        // If the entity type is translatable, ensure we return the proper
        // translation object for the current context.
        if ($entity instanceof EntityInterface && $entity instanceof TranslatableInterface) {
            $entity = $this->entityRepository
                ->getTranslationFromContext($entity, NULL, [
                'operation' => 'entity_upcast',
            ]);
        }
        return $entity;
    }
    
    /**
     * {@inheritdoc}
     */
    public function applies($definition, $name, Route $route) {
        return isset($definition['type']) && strpos($definition['type'], 'entity_revision:') !== FALSE;
    }

}