function hook_html_head_alter

Alter XHTML HEAD tags before they are rendered by backdrop_get_html_head().

Elements available to be altered are only those added using backdrop_add_html_head_link() or backdrop_add_html_head(). CSS and JS files are handled using backdrop_add_css() and backdrop_add_js(), so the head links for those files will not appear in the $head_elements array.

Parameters

$head_elements: An array of renderable elements. Generally the values of the #attributes array will be the most likely target for changes.

Related topics

File

core/modules/system/system.api.php, line 3453

Hooks provided by Backdrop core and the System module.

Code

function hook_html_head_alter(&$head_elements) {
  foreach ($head_elements as $key => $element) {
    if (isset($element['#attributes']['rel']) && $element['#attributes']['rel'] == 'canonical') {
      // I want a custom canonical URL.
      $head_elements[$key]['#attributes']['href'] = my_module_canonical_url();
    }
  }
}