--- /dev/null
+/**
+ * Implements hook_html_head_alter().
+ */
+function {{ machine_name }}_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'] = mymodule_canonical_url();
+ }
+ }
+}