function _toolbar_initialize_page_cache

Use Drupal's page cache for toolbar/subtrees/*, even for authenticated users.

This gets invoked after full bootstrap, so must duplicate some of what's done by _drupal_bootstrap_page_cache().

@todo Replace this hack with something better integrated with DrupalKernel once Drupal's page caching itself is properly integrated.

File

drupal/core/modules/toolbar/toolbar.module, line 95

Administration toolbar for quick access to top level administration items.

Code

function _toolbar_initialize_page_cache() {
  $GLOBALS['conf']['system.performance']['cache']['page']['enabled'] = TRUE;
  drupal_page_is_cacheable(TRUE);

  // If we have a cache, serve it.
  // @see _drupal_bootstrap_page_cache()
  $cache = drupal_page_get_cache();
  if (is_object($cache)) {
    header('X-Drupal-Cache: HIT');

    // Restore the metadata cached with the page.
    $_GET['q'] = $cache->data['path'];
    date_default_timezone_set(drupal_get_user_timezone());
    drupal_serve_page_from_cache($cache);

    // We are done.
    exit;
  }

  // Otherwise, create a new page response (that will be cached).
  header('X-Drupal-Cache: MISS');

  // The Expires HTTP header is the heart of the client-side HTTP caching. The
  // additional server-side page cache only takes effect when the client
  // accesses the callback URL again (e.g., after clearing the browser cache or
  // when force-reloading a Drupal page).
  $max_age = 3600 * 24 * 365;
  drupal_add_http_header('Expires', gmdate(DATE_RFC1123, REQUEST_TIME + $max_age));
  drupal_add_http_header('Cache-Control', 'private, max-age=' . $max_age);
}