Issue #1534490 by msonnabaum, bigjim, David_Rothstein, pounard, Dave Reid: Make block cache cids alterable

2 files changed, 26 insertions, 0 deletions

diff --git a/modules/block/block.api.php b/modules/block/block.api.php
index d7453b24b..e38f7d6ee 100644
--- a/modules/block/block.api.php
+++ b/modules/block/block.api.php
@@ -364,5 +364,30 @@ function hook_block_list_alter(&$blocks) {
 }
 
 /**
+ * Act on block cache ID (cid) parts before the cid is generated.
+ *
+ * This hook allows you to add, remove or modify the custom keys used to
+ * generate a block cache ID (by default, these keys are set to the block
+ * module and delta). These keys will be combined with the standard ones
+ * provided by drupal_render_cid_parts() to generate the final block cache ID.
+ *
+ * To change the cache granularity used by drupal_render_cid_parts(), this hook
+ * cannot be used; instead, set the 'cache' key in the block's definition in
+ * hook_block_info().
+ *
+ * @params $cid_parts
+ *   An array of elements used to build the cid.
+ * @param $block
+ *   The block object being acted on.
+ *
+ * @see _block_get_cache_id()
+ */
+function hook_block_cid_parts_alter(&$cid_parts, $block) {
+  global $user;
+  // This example shows how to cache a block based on the user's timezone.
+  $cid_parts[] = $user->timezone;
+}
+
+/**
  * @} End of "addtogroup hooks".
  */
diff --git a/modules/block/block.module b/modules/block/block.module
index 48c80d766..fe04e9902 100644
--- a/modules/block/block.module
+++ b/modules/block/block.module
@@ -967,6 +967,7 @@ function _block_get_cache_id($block) {
     // Start with common sub-patterns: block identification, theme, language.
     $cid_parts[] = $block->module;
     $cid_parts[] = $block->delta;
+    drupal_alter('block_cid_parts', $cid_parts, $block);
     $cid_parts = array_merge($cid_parts, drupal_render_cid_parts($block->cache));
 
     return implode(':', $cid_parts);