function drupal_render_cid_parts

Returns cache ID parts for building a cache ID.


$granularity: One or more cache granularity constants. For example, to cache separately for each user, use DRUPAL_CACHE_PER_USER. To cache separately for each page and role, use the expression:


Return value

An array of cache ID parts, always containing the active theme. If the locale module is enabled it also contains the active language. If $granularity was passed in, more parts are added.

3 calls to drupal_render_cid_parts()
drupal_render_cache_by_query in drupal/includes/
Prepares an element for caching based on a query.
drupal_render_cid_create in drupal/includes/
Creates the cache ID for a renderable element.
_block_get_cache_id in drupal/modules/block/block.module
Assemble the cache_id to use for a given block.


drupal/includes/, line 6390
Common functions that many Drupal modules will need to reference.


function drupal_render_cid_parts($granularity = NULL) {
  global $theme, $base_root, $user;
  $cid_parts[] = $theme;

  // If Locale is enabled but we have only one language we do not need it as cid
  // part.
  if (drupal_multilingual()) {
    foreach (language_types_configurable() as $language_type) {
      $cid_parts[] = $GLOBALS[$language_type]->language;
  if (!empty($granularity)) {
    $cache_per_role = $granularity & DRUPAL_CACHE_PER_ROLE;
    $cache_per_user = $granularity & DRUPAL_CACHE_PER_USER;

    // User 1 has special permissions outside of the role system, so when
    // caching per role is requested, it should cache per user instead.
    if ($user->uid == 1 && $cache_per_role) {
      $cache_per_user = TRUE;
      $cache_per_role = FALSE;

    // 'PER_ROLE' and 'PER_USER' are mutually exclusive. 'PER_USER' can be a
    // resource drag for sites with many users, so when a module is being
    // equivocal, we favor the less expensive 'PER_ROLE' pattern.
    if ($cache_per_role) {
      $cid_parts[] = 'r.' . implode(',', array_keys($user->roles));
    elseif ($cache_per_user) {
      $cid_parts[] = "u.{$user->uid}";
    if ($granularity & DRUPAL_CACHE_PER_PAGE) {
      $cid_parts[] = $base_root . request_uri();
  return $cid_parts;