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firewizard/Zend_Cache_Backend_Memcached.php

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Zend_Cache_Backend_Memcached.php
<?php
/**
* Zend Framework
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package Zend_Cache
* @subpackage Zend_Cache_Backend
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: Memcached.php 22207 2010-05-20 16:47:16Z mabe $
*/
/**
* @see Zend_Cache_Backend_Interface
*/
#require_once 'Zend/Cache/Backend/ExtendedInterface.php';
/**
* @see Zend_Cache_Backend
*/
#require_once 'Zend/Cache/Backend.php';
/**
* @package Zend_Cache
* @subpackage Zend_Cache_Backend
* @copyright Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Cache_Backend_Memcached extends Zend_Cache_Backend implements Zend_Cache_Backend_ExtendedInterface
{
/**
* Default Values
*/
const DEFAULT_HOST = '127.0.0.1';
const DEFAULT_PORT = 11211;
const DEFAULT_PERSISTENT = true;
const DEFAULT_WEIGHT = 1;
const DEFAULT_TIMEOUT = 1;
const DEFAULT_RETRY_INTERVAL = 15;
const DEFAULT_STATUS = true;
const DEFAULT_FAILURE_CALLBACK = null;
/**
* Log message
*/
const TAGS_UNSUPPORTED_BY_CLEAN_OF_MEMCACHED_BACKEND = 'Zend_Cache_Backend_Memcached::clean() : tags are unsupported by the Memcached backend';
const TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND = 'Zend_Cache_Backend_Memcached::save() : tags are unsupported by the Memcached backend';
/**
* Available options
*
* =====> (array) servers :
* an array of memcached server ; each memcached server is described by an associative array :
* 'host' => (string) : the name of the memcached server
* 'port' => (int) : the port of the memcached server
* 'persistent' => (bool) : use or not persistent connections to this memcached server
* 'weight' => (int) : number of buckets to create for this server which in turn control its
* probability of it being selected. The probability is relative to the total
* weight of all servers.
* 'timeout' => (int) : value in seconds which will be used for connecting to the daemon. Think twice
* before changing the default value of 1 second - you can lose all the
* advantages of caching if your connection is too slow.
* 'retry_interval' => (int) : controls how often a failed server will be retried, the default value
* is 15 seconds. Setting this parameter to -1 disables automatic retry.
* 'status' => (bool) : controls if the server should be flagged as online.
* 'failure_callback' => (callback) : Allows the user to specify a callback function to run upon
* encountering an error. The callback is run before failover
* is attempted. The function takes two parameters, the hostname
* and port of the failed server.
*
* =====> (boolean) compression :
* true if you want to use on-the-fly compression
*
* =====> (boolean) compatibility :
* true if you use old memcache server or extension
*
* @var array available options
*/
protected $_options = array(
'servers' => array(array(
'host' => self::DEFAULT_HOST,
'port' => self::DEFAULT_PORT,
'persistent' => self::DEFAULT_PERSISTENT,
'weight' => self::DEFAULT_WEIGHT,
'timeout' => self::DEFAULT_TIMEOUT,
'retry_interval' => self::DEFAULT_RETRY_INTERVAL,
'status' => self::DEFAULT_STATUS,
'failure_callback' => self::DEFAULT_FAILURE_CALLBACK
)),
'compression' => false,
'compatibility' => false,
);
/**
* Memcache object
*
* @var mixed memcache object
*/
protected $_memcache = null;
/**
* Constructor
*
* @param array $options associative array of options
* @throws Zend_Cache_Exception
* @return void
*/
public function __construct(array $options = array())
{
if (!extension_loaded('memcache')) {
Zend_Cache::throwException('The memcache extension must be loaded for using this backend !');
}
parent::__construct($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);
}
$this->_memcache = new Memcache;
foreach ($this->_options['servers'] as $server) {
if (!array_key_exists('port', $server)) {
$server['port'] = self::DEFAULT_PORT;
}
if (!array_key_exists('persistent', $server)) {
$server['persistent'] = self::DEFAULT_PERSISTENT;
}
if (!array_key_exists('weight', $server)) {
$server['weight'] = self::DEFAULT_WEIGHT;
}
if (!array_key_exists('timeout', $server)) {
$server['timeout'] = self::DEFAULT_TIMEOUT;
}
if (!array_key_exists('retry_interval', $server)) {
$server['retry_interval'] = self::DEFAULT_RETRY_INTERVAL;
}
if (!array_key_exists('status', $server)) {
$server['status'] = self::DEFAULT_STATUS;
}
if (!array_key_exists('failure_callback', $server)) {
$server['failure_callback'] = self::DEFAULT_FAILURE_CALLBACK;
}
if ($this->_options['compatibility']) {
// No status for compatibility mode (#ZF-5887)
$this->_memcache->addServer($server['host'], $server['port'], $server['persistent'],
$server['weight'], $server['timeout'],
$server['retry_interval']);
} else {
$this->_memcache->addServer($server['host'], $server['port'], $server['persistent'],
$server['weight'], $server['timeout'],
$server['retry_interval'],
$server['status'], $server['failure_callback']);
}
}
}
/**
* Test if a cache is available for the given id and (if yes) return it (false else)
*
* @param string $id Cache id
* @param boolean $doNotTestCacheValidity If set to true, the cache validity won't be tested
* @return string|false cached datas
*/
public function load($id, $doNotTestCacheValidity = false)
{
$tmp = $this->_memcache->get($id);
if (is_array($tmp) && isset($tmp[0])) {
return $tmp[0];
}
return false;
}
/**
* Test if a cache is available or not (for the given id)
*
* @param string $id Cache id
* @return mixed|false (a cache is not available) or "last modified" timestamp (int) of the available cache record
*/
public function test($id)
{
$tmp = $this->_memcache->get($id);
if (is_array($tmp)) {
return $tmp[1];
}
return false;
}
/**
* Save some string datas into a cache record
*
* Note : $data is always "string" (serialization is done by the
* core not by the backend)
*
* @param string $data Datas to cache
* @param string $id Cache id
* @param array $tags Array of strings, the cache record will be tagged by each string entry
* @param int $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime)
* @return boolean True if no problem
*/
public function save($data, $id, $tags = array(), $specificLifetime = false)
{
$lifetime = $this->getLifetime($specificLifetime);
if ($this->_options['compression']) {
$flag = MEMCACHE_COMPRESSED;
} else {
$flag = 0;
}
// ZF-8856: using set because add needs a second request if item already exists
$result = @$this->_memcache->set($id, array($data, time(), $lifetime), $flag, $lifetime);
if (count($tags) > 0) {
$this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
}
return $result;
}
/**
* Remove a cache record
*
* @param string $id Cache id
* @return boolean True if no problem
*/
public function remove($id)
{
return $this->_memcache->delete($id, 0);
}
/**
* Clean some cache records
*
* Available modes are :
* 'all' (default) => remove all cache entries ($tags is not used)
* 'old' => unsupported
* 'matchingTag' => unsupported
* 'notMatchingTag' => unsupported
* 'matchingAnyTag' => unsupported
*
* @param string $mode Clean mode
* @param array $tags Array of tags
* @throws Zend_Cache_Exception
* @return boolean True if no problem
*/
public function clean($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_Memcached::clean() : CLEANING_MODE_OLD is unsupported by the Memcached 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_MEMCACHED_BACKEND);
break;
default:
Zend_Cache::throwException('Invalid mode for clean() method');
break;
}
}
/**
* Return true if the automatic cleaning is available for the backend
*
* @return boolean
*/
public function isAutomaticCleaningAvailable()
{
return false;
}
/**
* Set the frontend directives
*
* @param array $directives Assoc of directives
* @throws Zend_Cache_Exception
* @return void
*/
public function setDirectives($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));
}
}
/**
* Return an array of stored cache ids
*
* @return array array of stored cache ids (string)
*/
public function getIds()
{
$this->_log("Zend_Cache_Backend_Memcached::save() : getting the list of cache ids is unsupported by the Memcache backend");
return array();
}
/**
* Return an array of stored tags
*
* @return array array of stored tags (string)
*/
public function getTags()
{
$this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
return array();
}
/**
* Return an array of stored cache ids which match given tags
*
* In case of multiple tags, a logical AND is made between tags
*
* @param array $tags array of tags
* @return array array of matching cache ids (string)
*/
public function getIdsMatchingTags($tags = array())
{
$this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
return array();
}
/**
* Return an array of stored cache ids which don't match given tags
*
* In case of multiple tags, a logical OR is made between tags
*
* @param array $tags array of tags
* @return array array of not matching cache ids (string)
*/
public function getIdsNotMatchingTags($tags = array())
{
$this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
return array();
}
/**
* Return an array of stored cache ids which match any given tags
*
* In case of multiple tags, a logical AND is made between tags
*
* @param array $tags array of tags
* @return array array of any matching cache ids (string)
*/
public function getIdsMatchingAnyTags($tags = array())
{
$this->_log(self::TAGS_UNSUPPORTED_BY_SAVE_OF_MEMCACHED_BACKEND);
return array();
}
/**
* Return the filling percentage of the backend storage
*
* @throws Zend_Cache_Exception
* @return int integer between 0 and 100
*/
public function getFillingPercentage()
{
$mems = $this->_memcache->getExtendedStats();
$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) {
$mem = $this->_memcache->getstats();
if (isset($mem['limit_maxbytes']) && $mem['limit_maxbytes'] > 0) {
return ((int) (100 * ($mem['bytes'] / $mem['limit_maxbytes'])));
} else {
return 100;
}
//Zend_Cache::throwException('Can\'t get filling percentage');
}
return ((int) (100. * ($memUsed / $memSize)));
}
/**
* Return an array of metadatas for the given cache id
*
* The array must include these keys :
* - expire : the expire timestamp
* - tags : a string array of tags
* - mtime : timestamp of last modification time
*
* @param string $id cache id
* @return array array of metadatas (false if the cache id is not found)
*/
public function getMetadatas($id)
{
$tmp = $this->_memcache->get($id);
if (is_array($tmp)) {
$data = $tmp[0];
$mtime = $tmp[1];
if (!isset($tmp[2])) {
// because this record is only with 1.7 release
// if old cache records are still there...
return false;
}
$lifetime = $tmp[2];
return array(
'expire' => $mtime + $lifetime,
'tags' => array(),
'mtime' => $mtime
);
}
return false;
}
/**
* Give (if possible) an extra lifetime to the given cache id
*
* @param string $id cache id
* @param int $extraLifetime
* @return boolean true if ok
*/
public function touch($id, $extraLifetime)
{
if ($this->_options['compression']) {
$flag = MEMCACHE_COMPRESSED;
} else {
$flag = 0;
}
$tmp = $this->_memcache->get($id);
if (is_array($tmp)) {
$data = $tmp[0];
$mtime = $tmp[1];
if (!isset($tmp[2])) {
// because this record is only with 1.7 release
// if old cache records are still there...
return false;
}
$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), $flag, $newLifetime))) {
$result = $this->_memcache->set($id, array($data, time(), $newLifetime), $flag, $newLifetime);
}
return $result;
}
return false;
}
/**
* Return an associative array of capabilities (booleans) of the backend
*
* The array must include these keys :
* - automatic_cleaning (is automating cleaning necessary)
* - tags (are tags supported)
* - expired_read (is it possible to read expired cache records
* (for doNotTestCacheValidity option for example))
* - priority does the backend deal with priority when saving
* - infinite_lifetime (is infinite lifetime can work with this backend)
* - get_list (is it possible to get the list of cache ids and the complete list of tags)
*
* @return array associative of with capabilities
*/
public function getCapabilities()
{
return array(
'automatic_cleaning' => false,
'tags' => false,
'expired_read' => false,
'priority' => false,
'infinite_lifetime' => false,
'get_list' => false
);
}
}
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