function content_translation_page_attachments

Implements hook_page_attachments().

File

core/modules/content_translation/content_translation.module, line 668

Allows entities to be translated into different languages.

Code

function content_translation_page_attachments(&$page) {
  $cache = CacheableMetadata::createFromRenderArray($page);
  $route_match = \Drupal::routeMatch();

  // If the current route has no parameters, return.
  if (!($route = $route_match
    ->getRouteObject()) || !($parameters = $route
    ->getOption('parameters'))) {
    return;
  }
  $is_front = \Drupal::service('path.matcher')
    ->isFrontPage();

  // Determine if the current route represents an entity.
  foreach ($parameters as $name => $options) {
    if (!isset($options['type']) || !str_starts_with($options['type'], 'entity:')) {
      continue;
    }
    $entity = $route_match
      ->getParameter($name);
    if ($entity instanceof ContentEntityInterface && $entity
      ->hasLinkTemplate('canonical')) {

      // Current route represents a content entity. Build hreflang links.
      foreach ($entity
        ->getTranslationLanguages() as $language) {

        // Skip any translation that cannot be viewed.
        $translation = $entity
          ->getTranslation($language
          ->getId());
        $access = $translation
          ->access('view', NULL, TRUE);
        $cache
          ->addCacheableDependency($access);
        if (!$access
          ->isAllowed()) {
          continue;
        }
        if ($is_front) {

          // If the current page is front page, do not create hreflang links
          // from the entity route, just add the languages to root path.
          $url = Url::fromRoute('<front>', [], [
            'absolute' => TRUE,
            'language' => $language,
          ])
            ->toString();
        }
        else {
          $url = $entity
            ->toUrl('canonical')
            ->setOption('language', $language)
            ->setAbsolute()
            ->toString();
        }
        $page['#attached']['html_head_link'][] = [
          [
            'rel' => 'alternate',
            'hreflang' => $language
              ->getId(),
            'href' => $url,
          ],
        ];
      }
    }

    // Since entity was found, no need to iterate further.
    break;
  }

  // Apply updated caching information.
  $cache
    ->applyTo($page);
}