Libmemcached.php

Go to the documentation of this file.

<?php
#require_once 'Zend/Cache/Backend/ExtendedInterface.php';

#require_once 'Zend/Cache/Backend.php';


class Zend_Cache_Backend_Libmemcached extends Zend_Cache_Backend implements Zend_Cache_Backend_ExtendedInterface
{
    const DEFAULT_HOST = '127.0.0.1';
    const DEFAULT_PORT =  11211;
    const DEFAULT_WEIGHT  = 1;

    const TAGS_UNSUPPORTED_BY_CLEAN_OF_LIBMEMCACHED_BACKEND = 'Zend_Cache_Backend_Libmemcached::clean() : tags are unsupported by the Libmemcached backend';
    const TAGS_UNSUPPORTED_BY_SAVE_OF_LIBMEMCACHED_BACKEND =  'Zend_Cache_Backend_Libmemcached::save() : tags are unsupported by the Libmemcached backend';

    protected $_options = array(
        'servers' => array(array(
            'host'   => self::DEFAULT_HOST,
            'port'   => self::DEFAULT_PORT,
            'weight' => self::DEFAULT_WEIGHT,
        )),
        'client' => array()
    );

    protected $_memcache = null;

    public function __construct(array $options = array())
    {
        if (!extension_loaded('memcached')) {
            Zend_Cache::throwException('The memcached extension must be loaded for using this backend !');
        }

        // override default client options
        $this->_options['client'] = array(
            Memcached::OPT_DISTRIBUTION         => Memcached::DISTRIBUTION_CONSISTENT,
            Memcached::OPT_HASH                 => Memcached::HASH_MD5,
            Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
        );

        parent::__construct($options);

        if (isset($this->_options['servers'])) {
            $value = $this->_options['servers'];
            if (isset($value['host'])) {
                // in this case, $value seems to be a simple associative array (one server only)
                $value = array(0 => $value); // let's transform it into a classical array of associative arrays
            }
            $this->setOption('servers', $value);
        }
        $this->_memcache = new Memcached;

        // setup memcached client options
        foreach ($this->_options['client'] as $name => $value) {
            $optId = null;
            if (is_int($name)) {
                $optId = $name;
            } else {
                $optConst = 'Memcached::OPT_' . strtoupper($name);
                if (defined($optConst)) {
                    $optId = constant($optConst);
                } else {
                    $this->_log("Unknown memcached client option '{$name}' ({$optConst})");
                }
            }
            if (null !== $optId) {
                if (!$this->_memcache->setOption($optId, $value)) {
                    $this->_log("Setting memcached client option '{$optId}' failed");
                }
            }
        }

        // setup memcached servers
        $servers = array();
        foreach ($this->_options['servers'] as $server) {
            if (!array_key_exists('port', $server)) {
                $server['port'] = self::DEFAULT_PORT;
            }
            if (!array_key_exists('weight', $server)) {
                $server['weight'] = self::DEFAULT_WEIGHT;
            }

            $servers[] = array($server['host'], $server['port'], $server['weight']);
        }
        $this->_memcache->addServers($servers);
    }

    public function load($id, $doNotTestCacheValidity = false)
    {
        $tmp = $this->_memcache->get($id);
        if (isset($tmp[0])) {
            return $tmp[0];
        }
        return false;
    }

    public function test($id)
    {
        $tmp = $this->_memcache->get($id);
        if (isset($tmp[0], $tmp[1])) {
            return (int)$tmp[1];
        }
        return false;
    }

    public function save($data, $id, $tags = array(), $specificLifetime = false)
    {
        $lifetime = $this->getLifetime($specificLifetime);

        // ZF-8856: using set because add needs a second request if item already exists
        $result = @$this->_memcache->set($id, array($data, time(), $lifetime), $lifetime);
        if ($result === false) {
            $rsCode = $this->_memcache->getResultCode();
            $rsMsg  = $this->_memcache->getResultMessage();
            $this->_log("Memcached::set() failed: [{$rsCode}] {$rsMsg}");
        }

        if (count($tags) > 0) {
            $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_LIBMEMCACHED_BACKEND);
        }

        return $result;
    }

    public function remove($id)
    {
        return $this->_memcache->delete($id);
    }

    public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
    {
        switch ($mode) {
            case Zend_Cache::CLEANING_MODE_ALL:
                return $this->_memcache->flush();
                break;
            case Zend_Cache::CLEANING_MODE_OLD:
                $this->_log("Zend_Cache_Backend_Libmemcached::clean() : CLEANING_MODE_OLD is unsupported by the Libmemcached backend");
                break;
            case Zend_Cache::CLEANING_MODE_MATCHING_TAG:
            case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG:
            case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG:
                $this->_log(self::TAGS_UNSUPPORTED_BY_CLEAN_OF_LIBMEMCACHED_BACKEND);
                break;
               default:
                Zend_Cache::throwException('Invalid mode for clean() method');
                   break;
        }
    }

    public function isAutomaticCleaningAvailable()
    {
        return false;
    }

    public function setDirectives($directives)
    {
        parent::setDirectives($directives);
        $lifetime = $this->getLifetime(false);
        if ($lifetime > 2592000) {
            // #ZF-3490 : For the memcached backend, there is a lifetime limit of 30 days (2592000 seconds)
            $this->_log('memcached backend has a limit of 30 days (2592000 seconds) for the lifetime');
        }
        if ($lifetime === null) {
            // #ZF-4614 : we tranform null to zero to get the maximal lifetime
            parent::setDirectives(array('lifetime' => 0));
        }
    }

    public function getIds()
    {
        $this->_log("Zend_Cache_Backend_Libmemcached::save() : getting the list of cache ids is unsupported by the Libmemcached backend");
        return array();
    }

    public function getTags()
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_LIBMEMCACHED_BACKEND);
        return array();
    }

    public function getIdsMatchingTags($tags = array())
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_LIBMEMCACHED_BACKEND);
        return array();
    }

    public function getIdsNotMatchingTags($tags = array())
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_LIBMEMCACHED_BACKEND);
        return array();
    }

    public function getIdsMatchingAnyTags($tags = array())
    {
        $this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_LIBMEMCACHED_BACKEND);
        return array();
    }

    public function getFillingPercentage()
    {
        $mems = $this->_memcache->getStats();
        if ($mems === false) {
            return 0;
        }

        $memSize = null;
        $memUsed = null;
        foreach ($mems as $key => $mem) {
            if ($mem === false) {
                $this->_log('can\'t get stat from ' . $key);
                continue;
            }

            $eachSize = $mem['limit_maxbytes'];
            $eachUsed = $mem['bytes'];
            if ($eachUsed > $eachSize) {
                $eachUsed = $eachSize;
            }

            $memSize += $eachSize;
            $memUsed += $eachUsed;
        }

        if ($memSize === null || $memUsed === null) {
            Zend_Cache::throwException('Can\'t get filling percentage');
        }

        return ((int) (100. * ($memUsed / $memSize)));
    }

    public function getMetadatas($id)
    {
        $tmp = $this->_memcache->get($id);
        if (isset($tmp[0], $tmp[1], $tmp[2])) {
            $data     = $tmp[0];
            $mtime    = $tmp[1];
            $lifetime = $tmp[2];
            return array(
                'expire' => $mtime + $lifetime,
                'tags' => array(),
                'mtime' => $mtime
            );
        }

        return false;
    }

    public function touch($id, $extraLifetime)
    {
        $tmp = $this->_memcache->get($id);
        if (isset($tmp[0], $tmp[1], $tmp[2])) {
            $data     = $tmp[0];
            $mtime    = $tmp[1];
            $lifetime = $tmp[2];
            $newLifetime = $lifetime - (time() - $mtime) + $extraLifetime;
            if ($newLifetime <=0) {
                return false;
            }
            // #ZF-5702 : we try replace() first becase set() seems to be slower
            if (!($result = $this->_memcache->replace($id, array($data, time(), $newLifetime), $newLifetime))) {
                $result = $this->_memcache->set($id, array($data, time(), $newLifetime), $newLifetime);
                if ($result === false) {
                    $rsCode = $this->_memcache->getResultCode();
                    $rsMsg  = $this->_memcache->getResultMessage();
                    $this->_log("Memcached::set() failed: [{$rsCode}] {$rsMsg}");
                }
            }
            return $result;
        }
        return false;
    }

    public function getCapabilities()
    {
        return array(
            'automatic_cleaning' => false,
            'tags' => false,
            'expired_read' => false,
            'priority' => false,
            'infinite_lifetime' => false,
            'get_list' => false
        );
    }

}