You are here

Home » API reference » Smart Paging 7 » smart_paging.module

function smart_paging_html_head_alter in Smart Paging 7

Same name and namespace in other branches
  1. 7.2 smart_paging.module \smart_paging_html_head_alter()

Implements hook_html_head_alter(). Smart Paging as better SEO friendly targeting meta tags

File

./smart_paging.module, line 1094
Provides smart paging capability to Drupal contents.

Code

function smart_paging_html_head_alter(&$head_elements) {
  global $base_root;
  if (isset($head_elements['smart_paging_link_canonical'])) {

    // Process the canonical.
    $smart_paging_canonical['smart_paging_link_canonical'] = $head_elements['smart_paging_link_canonical'];
    unset($head_elements['smart_paging_link_canonical']);
    $current_alias = function_exists('path_alias_xt_get_path_alias') ? path_alias_xt_get_path_alias($_GET['q']) : drupal_get_path_alias($_GET['q']);
    $current_absolute_alias = url($_GET['q'], array(
      'absolute' => TRUE,
    ));
    $override_canonical = array();

    // Collect other existing canonical element(s)
    foreach ($head_elements as $head_element_key => $head_element) {
      $canonical_tag = isset($head_element['#tag']) && $head_element['#tag'] == 'link' && isset($head_element['#attributes']) && $head_element['#attributes']['rel'] == 'canonical';
      $canonical_metatag = $head_element_key == 'metatag_canonical';

      // Drupal standard canonical link style plus metatag edge case - does not overwrite standard drupal
      if (strpos($head_element_key, 'drupal_add_html_head_link:canonical') === 0 || $canonical_tag || $canonical_metatag) {

        // If other canonicals are different from the base url (page1), collect them.
        // Check absolute url alias for page as well, this should allow Domain Source, or other absolute, provided canonical to be authoratative.
        if ($canonical_tag && $head_element['#attributes']['href'] != $current_alias && $head_element['#attributes']['href'] != $current_absolute_alias || $canonical_metatag && $head_element['#value'] != $current_alias && $head_element['#value'] != $current_absolute_alias) {
          $override_canonical[$head_element_key] = $head_element;
        }
        unset($head_elements[$head_element_key]);
      }
    }

    // If there are existing canonicals that don't match the base url, use them
    // We are erring on the side that if another module is specifying a canonical different from this page's root (page1) then we shouldn't change it.
    if (!empty($override_canonical)) {
      $head_elements = array_merge($head_elements, $override_canonical);
    }
    else {

      // Otherwise use the smart_paging canonical
      $head_elements = array_merge($head_elements, $smart_paging_canonical);

      // Remove any other canonicals already in the http response
      // Here we are assuming that if the canonicals in the <head> element are ok to override, so is the http header
      $http_header_link = drupal_get_http_header('Link');
      $http_header_link = explode(',', $http_header_link);
      foreach ($http_header_link as $key => $link) {
        if (preg_match('#rel="canonical"#i', $link)) {
          unset($http_header_link[$key]);
        }
      }
      drupal_add_http_header('Link', implode(',', $http_header_link));
    }
  }
  if (isset($head_elements['smart_paging_seo'])) {
    $smart_paging_seo = json_decode($head_elements['smart_paging_seo']['#attributes']['content']);
    $tags = array();
    if (!empty($smart_paging_seo)) {
      foreach ($smart_paging_seo as $tag => $tag_content) {
        $target_tag = explode('_', $tag);
        if (isset($target_tag[0]) && isset($target_tag[1]) && isset($target_tag[2]) && isset($target_tag[3])) {
          $tags[$target_tag[2]] = array(
            'attr_name' => $target_tag[1],
            'tag' => $target_tag[0],
            'content_attr' => $target_tag[3],
            'content' => $tag_content,
          );
        }
      }
    }
    if (!empty($tags)) {
      foreach ($head_elements as $head_element_key => $head_element) {
        foreach ($tags as $target_name => $attr) {
          if ($head_element['#tag'] == $attr['tag'] && (isset($head_element['#attributes'][$attr['attr_name']]) && $head_element['#attributes'][$attr['attr_name']] == $target_name)) {
            if (!empty($attr['content'])) {
              $head_elements[$head_element_key]['#attributes'][$attr['content_attr']] = $attr['content'];
            }
            else {
              unset($head_elements[$head_element_key]);
            }
            unset($tags[$target_name]);
          }
        }
      }
    }
    unset($head_elements['smart_paging_seo']);
    if (!empty($tags)) {
      foreach ($tags as $target_name => $attr) {
        $head_elements["smart_paging_{$target_name}"] = array(
          '#type' => 'html_tag',
          '#tag' => $attr['tag'],
          '#attributes' => array(
            $attr['attr_name'] => $target_name,
            $attr['content_attr'] => $attr['content'],
          ),
        );
        unset($tags[$target_name]);
      }
    }
  }
}