Class **Phalcon\\Cache\\Backend\\Libmemcached**
===============================================

*extends* abstract class :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

*implements* :doc:`Phalcon\\Cache\\BackendInterface <Phalcon_Cache_BackendInterface>`

.. role:: raw-html(raw)
   :format: html

:raw-html:`<a href="https://github.com/phalcon/cphalcon/blob/master/phalcon/cache/backend/libmemcached.zep" class="btn btn-default btn-sm">Source on GitHub</a>`

Allows to cache output fragments, PHP data or raw data to a libmemcached backend.
Per default persistent memcached connection pools are used.

.. code-block:: php

    <?php

    use Phalcon\Cache\Backend\Libmemcached;
    use Phalcon\Cache\Frontend\Data as FrontData;

    // Cache data for 2 days
    $frontCache = new FrontData(
        [
            "lifetime" => 172800,
        ]
    );

    // Create the Cache setting memcached connection options
    $cache = new Libmemcached(
        $frontCache,
        [
            "servers" => [
                [
                    "host"   => "127.0.0.1",
                    "port"   => 11211,
                    "weight" => 1,
                ],
            ],
            "client" => [
                \Memcached::OPT_HASH       => \Memcached::HASH_MD5,
                \Memcached::OPT_PREFIX_KEY => "prefix.",
            ],
        ]
    );

    // Cache arbitrary data
    $cache->save("my-data", [1, 2, 3, 4, 5]);

    // Get data
    $data = $cache->get("my-data");



Methods
-------

public  **__construct** (:doc:`Phalcon\\Cache\\FrontendInterface <Phalcon_Cache_FrontendInterface>` $frontend, [*array* $options])

Phalcon\\Cache\\Backend\\Memcache constructor



public  **_connect** ()

Create internal connection to memcached



public  **get** (*mixed* $keyName, [*mixed* $lifetime])

Returns a cached content



public  **save** ([*int* | *string* $keyName], [*string* $content], [*int* $lifetime], [*boolean* $stopBuffer])

Stores cached content into the file backend and stops the frontend



public *boolean* **delete** (*int* | *string* $keyName)

Deletes a value from the cache by its key



public  **queryKeys** ([*mixed* $prefix])

Query the existing cached keys.

.. code-block:: php

    <?php

    $cache->save("users-ids", [1, 2, 3]);
    $cache->save("projects-ids", [4, 5, 6]);

    var_dump($cache->queryKeys("users")); // ["users-ids"]




public  **exists** ([*string* $keyName], [*int* $lifetime])

Checks if cache exists and it isn't expired



public  **increment** ([*string* $keyName], [*mixed* $value])

Increment of given $keyName by $value



public  **decrement** ([*string* $keyName], [*mixed* $value])

Decrement of $keyName by given $value



public  **flush** ()

Immediately invalidates all existing items.
Memcached does not support flush() per default. If you require flush() support, set $config["statsKey"].
All modified keys are stored in "statsKey". Note: statsKey has a negative performance impact.

.. code-block:: php

    <?php

    $cache = new \Phalcon\Cache\Backend\Libmemcached(
        $frontCache,
        [
            "statsKey" => "_PHCM",
        ]
    );

    $cache->save("my-data", [1, 2, 3, 4, 5]);

    // 'my-data' and all other used keys are deleted
    $cache->flush();




public  **getFrontend** () inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

...


public  **setFrontend** (*mixed* $frontend) inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

...


public  **getOptions** () inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

...


public  **setOptions** (*mixed* $options) inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

...


public  **getLastKey** () inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

...


public  **setLastKey** (*mixed* $lastKey) inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

...


public *mixed* **start** (*int* | *string* $keyName, [*int* $lifetime]) inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

Starts a cache. The keyname allows to identify the created fragment



public  **stop** ([*mixed* $stopBuffer]) inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

Stops the frontend without store any cached content



public  **isFresh** () inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

Checks whether the last cache is fresh or cached



public  **isStarted** () inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

Checks whether the cache has starting buffering or not



public *int* **getLifetime** () inherited from :doc:`Phalcon\\Cache\\Backend <Phalcon_Cache_Backend>`

Gets the last lifetime set