EntityBundleRouteEnhancer.php

<?php

namespace Drupal\Core\Entity\Enhancer;

use Drupal\Core\Routing\EnhancerInterface;
use Drupal\Core\Routing\RouteObjectInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Route;

/**
 * Sets the bundle parameter for routes with the _field_ui option.
 */
class EntityBundleRouteEnhancer implements EnhancerInterface {
  
  /**
   * The entity type manager service.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;
  
  /**
   * Constructs a EntityBundleRouteEnhancer object.
   *
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager service.
   */
  public function __construct(EntityTypeManagerInterface $entity_type_manager) {
    $this->entityTypeManager = $entity_type_manager;
  }
  
  /**
   * {@inheritdoc}
   */
  public function enhance(array $defaults, Request $request) {
    if (!$this->applies($defaults[RouteObjectInterface::ROUTE_OBJECT])) {
      return $defaults;
    }
    if (($bundle = $this->entityTypeManager
      ->getDefinition($defaults['entity_type_id'])
      ->getBundleEntityType()) && isset($defaults[$bundle])) {
      // Field UI forms only need the actual name of the bundle they're dealing
      // with, not an upcasted entity object, so provide a simple way for them
      // to get it.
      $defaults['bundle'] = $defaults['_raw_variables']->get($bundle);
    }
    return $defaults;
  }
  
  /**
   * {@inheritdoc}
   */
  protected function applies(Route $route) {
    return $route->hasOption('_field_ui');
  }

}