NodePreviewController.php

<?php

namespace Drupal\node\Controller;

use Drupal\Core\Entity\Controller\EntityViewController;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\EntityRepositoryInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Render\RendererInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Defines a controller to render a single node in preview.
 */
class NodePreviewController extends EntityViewController {
  
  /**
   * The entity repository service.
   *
   * @var \Drupal\Core\Entity\EntityRepositoryInterface
   */
  protected $entityRepository;
  
  /**
   * Creates a NodeViewController object.
   *
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager.
   * @param \Drupal\Core\Render\RendererInterface $renderer
   *   The renderer service.
   * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
   *   The entity repository.
   */
  public function __construct(EntityTypeManagerInterface $entity_type_manager, RendererInterface $renderer, EntityRepositoryInterface $entity_repository) {
    parent::__construct($entity_type_manager, $renderer);
    $this->entityRepository = $entity_repository;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static($container->get('entity_type.manager'), $container->get('renderer'), $container->get('entity.repository'));
  }
  
  /**
   * {@inheritdoc}
   */
  public function view(EntityInterface $node_preview, $view_mode_id = 'full', $langcode = NULL) {
    $node_preview->preview_view_mode = $view_mode_id;
    $build = parent::view($node_preview, $view_mode_id);
    $build['#attached']['library'][] = 'node/drupal.node.preview';
    // Don't render cache previews.
    unset($build['#cache']);
    return $build;
  }
  
  /**
   * The _title_callback for the page that renders a single node in preview.
   *
   * @param \Drupal\Core\Entity\EntityInterface $node_preview
   *   The current node.
   *
   * @return string
   *   The page title.
   *
   * @deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. There is no
   * replacement.
   * @see https://www.drupal.org/node/3518065
   */
  public function title(EntityInterface $node_preview) {
    @trigger_error(__METHOD__ . ' is deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. There is no replacement. See https://www.drupal.org/node/3518065', E_USER_DEPRECATED);
    return $this->entityRepository
      ->getTranslationFromContext($node_preview)
      ->label();
  }

}