function taxonomy_page_attachments_alter in Drupal 8

Implements hook_page_attachments_alter().

File

core/modules/taxonomy/taxonomy.module, line 105

Enables the organization of content into categories.

Code

function taxonomy_page_attachments_alter(array &$page) {
  $route_match = \Drupal::routeMatch();
  if ($route_match
    ->getRouteName() == 'entity.taxonomy_term.canonical' && ($term = $route_match
    ->getParameter('taxonomy_term')) && $term instanceof TermInterface) {
    foreach ($term
      ->uriRelationships() as $rel) {

      // Set the URI relationships, like canonical.
      $page['#attached']['html_head_link'][] = [
        [
          'rel' => $rel,
          'href' => $term
            ->toUrl($rel)
            ->toString(),
        ],
        TRUE,
      ];

      // Set the term path as the canonical URL to prevent duplicate content.
      if ($rel == 'canonical') {

        // Set the non-aliased canonical path as a default shortlink.
        $page['#attached']['html_head_link'][] = [
          [
            'rel' => 'shortlink',
            'href' => $term
              ->toUrl($rel, [
              'alias' => TRUE,
            ])
              ->toString(),
          ],
          TRUE,
        ];
      }
    }
  }
}