MetatagEnhancer.php

<?php

declare(strict_types = 1);

namespace Drupal\module_name\Plugin\jsonapi\FieldEnhancer;

use Drupal\Component\Render\PlainTextOutput;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\Core\Utility\Token;
use Drupal\jsonapi_extras\Plugin\ResourceFieldEnhancerBase;
use Drupal\metatag\MetatagManagerInterface;
use Shaper\Util\Context;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Prepare metatag value.
 *
 * @ResourceFieldEnhancer(
 *   id = "metatag",
 *   label = @Translation("Metatag (Metatag field only)"),
 *   description = @Translation("Add metatag values."),
 *   dependencies = {"metatag"}
 * )
 */
class MetatagEnhancer extends ResourceFieldEnhancerBase implements ContainerFactoryPluginInterface {

  /**
   * The metatag manager.
   *
   * @var \Drupal\metatag\MetatagManagerInterface
   */
  protected $metatagManager;

  /**
   * The token service.
   *
   * @var \Drupal\Core\Utility\Token
   */
  protected $token;

  /**
   * {@inheritdoc}
   */
  public function __construct(
    array $configuration,
    $plugin_id,
    array $plugin_definition,
    MetatagManagerInterface $metatag_manager,
    Token $token
  ) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->metatagManager = $metatag_manager;
    $this->token = $token;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->get('metatag.manager'),
      $container->get('token')
    );
  }

  /**
   * {@inheritdoc}
   */
  protected function doUndoTransform($data, Context $context) {
    $field_item = $context['field_item_object'];
    $entity = $field_item->getEntity();
    $metatags_for_entity = $this->metatagManager->tagsFromEntityWithDefaults($entity);
    $token_replacements = [$entity->getEntityTypeId() => $entity];
    $replacements_options['clear'] = TRUE;
    $data = [];
    foreach ($metatags_for_entity as $metatag_key => $metatag_for_entity) {
      $data[$metatag_key] = PlainTextOutput::renderFromHtml(htmlspecialchars_decode($this->token->replace($metatag_for_entity, $token_replacements, $replacements_options)));

      if (empty($data[$metatag_key])) {
        unset($data[$metatag_key]);
      }
    }

    return [
      'value' => $data,
    ];
  }

  /**
   * {@inheritdoc}
   */
  protected function doTransform($value, Context $context) {
    return $value;
  }

  /**
   * {@inheritdoc}
   */
  public function getOutputJsonSchema() {
    return [
      'type' => 'object',
    ];
  }

}