interface BackdropCacheInterface

Defines an interface for cache implementations.

All cache implementations have to implement this interface. BackdropDatabaseCache provides the default implementation, which can be consulted as an example.

To make Backdrop use your implementation for a certain cache bin, you have to set a value in settings.php with the name of the cache bin as its key and the name of your class as its value. For example, if your implementation of BackdropCacheInterface was called MyCustomCache, the following line in settings.php would make Backdrop use it for the 'cache_page' bin:

 $settings['cache_class_cache_page'] = 'MyCustomCache';

Additionally, you can register your cache implementation to be used by default for all cache bins by setting the $settings['cache_default_class'] to the name of your implementation of the BackdropCacheInterface, e.g.

 $settings['cache_default_class'] = 'MyCustomCache';

To implement a completely custom cache bin, use the same format:

 $settings['cache_class_custom_bin'] = 'MyCustomCache';

To access your custom cache bin, specify the name of the bin when storing or retrieving cached data:

 cache('custom_bin')->set($cid, $data, $expire);
 cache('custom_bin')->get($cid, 'custom_bin');

Implemented by

Hierarchy

interface BackdropCacheInterface

Expanded class hierarchy of BackdropCacheInterface

File

core/includes/cache.inc, line 248: Functions and interfaces for cache handling.

View source

interface BackdropCacheInterface {

  /**
   * Returns data from the persistent cache.
   *
   * Data may be stored as either plain text or as serialized data.
   * cache()->get() will automatically return unserialized objects and arrays.
   *
   * @param string $cid
   *   The cache ID of the data to retrieve.
   *
   * @return
   *   The cache or FALSE on failure.
   */
  function get($cid);

  /**
   * Returns data from the persistent cache when given an array of cache IDs.
   *
   * @param array $cids
   *   An array of cache IDs for the data to retrieve. This is passed by
   *   reference, and will have the IDs successfully returned from cache
   *   removed.
   *
   * @return
   *   An array of the items successfully returned from cache indexed by cid.
   */
  function getMultiple(array &$cids);

  /**
   * Stores data in the persistent cache.
   *
   * @param string $cid
   *   The cache ID of the data to store.
   * @param mixed $data
   *   The data to store in the cache. Complex data types will be automatically
   *   serialized before insertion. Strings will be stored as plain text and not
   *   serialized. Some storage engines only allow objects up to a maximum of
   *   1MB in size to be stored by default. When caching large arrays or
   *   similar, take care to ensure $data does not exceed this size.
   * @param int $expire
   *   (optional) Controls the maximum lifetime of this cache entry. Note that
   *   caches might be subject to clearing at any time, so this setting does not
   *   guarantee a minimum lifetime. With this in mind, the cache should not be
   *   used for data that must be kept during a cache clear, like sessions.
   *
   *   Use one of the following values:
   *   - CACHE_PERMANENT: Indicates that the item should never be removed unless
   *     explicitly told to using cache_clear_all() with a cache ID.
   *   - CACHE_TEMPORARY: Indicates that the item should be removed at the next
   *     general cache wipe.
   *   - A Unix timestamp: Indicates that the item should be kept at least until
   *     the given time, after which it behaves like CACHE_TEMPORARY.
   */
  function set($cid, $data, $expire = CACHE_PERMANENT);

  /**
   * Deletes an item from the cache.
   *
   * @param string $cid
   *    The cache ID to delete.
   */
  function delete($cid);

  /**
   * Deletes multiple items from the cache.
   *
   * @param $cids
   *   An array of $cids to delete.
   */
  function deleteMultiple(Array $cids);

  /**
   * Deletes items from the cache using a wildcard prefix.
   *
   * @param string $prefix
   *   A wildcard prefix.
   */
  function deletePrefix($prefix);

  /**
   * Flushes all cache items in a bin.
   */
  function flush();

  /**
   * Performs garbage collection on a cache bin. Removing expired items.
   */
  function garbageCollection();

  /**
   * Checks if a cache bin is empty.
   *
   * A cache bin is considered empty if it does not contain any valid data for
   * any cache ID.
   *
   * @return
   *   TRUE if the cache bin specified is empty.
   */
  function isEmpty();
}

Members

Name	Type	Description
BackdropCacheInterface::delete	function	Deletes an item from the cache.
BackdropCacheInterface::deleteMultiple	function	Deletes multiple items from the cache.
BackdropCacheInterface::deletePrefix	function	Deletes items from the cache using a wildcard prefix.
BackdropCacheInterface::flush	function	Flushes all cache items in a bin.
BackdropCacheInterface::garbageCollection	function	Performs garbage collection on a cache bin. Removing expired items.
BackdropCacheInterface::get	function	Returns data from the persistent cache.
BackdropCacheInterface::getMultiple	function	Returns data from the persistent cache when given an array of cache IDs.
BackdropCacheInterface::isEmpty	function	Checks if a cache bin is empty.
BackdropCacheInterface::set	function	Stores data in the persistent cache.

interface BackdropCacheInterface

Implemented by

Hierarchy

See also

File

Members