<?php /** * TMemCache class file * * @author Qiang Xue <qiang.xue@gmail.com> * @author Carl G. Mathisen <carlgmathisen@gmail.com> * @link http://www.pradosoft.com/ * @copyright Copyright © 2005-2008 PradoSoft * @license http://www.pradosoft.com/license/ * @version $Id$ * @package System.Caching */ /** * TMemCache class * * TMemCache implements a cache application module based on {@link http://www.danga.com/memcached/ memcached}. * * TMemCache can be configured with the Host and Port properties, which * specify the host and port of the memcache server to be used. * By default, they take the value 'localhost' and 11211, respectively. * These properties must be set before {@link init} is invoked. * * The following basic cache operations are implemented: * - {@link get} : retrieve the value with a key (if any) from cache * - {@link set} : store the value with a key into cache * - {@link add} : store the value only if cache does not have this key * - {@link delete} : delete the value with the specified key from cache * - {@link flush} : delete all values from cache * * Each value is associated with an expiration time. The {@link get} operation * ensures that any expired value will not be returned. The expiration time can * be specified by the number of seconds (maximum 60*60*24*30) * or a UNIX timestamp. A expiration time 0 represents never expire. * * By definition, cache does not ensure the existence of a value * even if it never expires. Cache is not meant to be an persistent storage. * * Also note, there is no security measure to protected data in memcache. * All data in memcache can be accessed by any process running in the system. * * To use this module, the memcache PHP extension must be loaded. * * Some usage examples of TMemCache are as follows, * <code> * $cache=new TMemCache; // TMemCache may also be loaded as a Prado application module * $cache->init(null); * $cache->add('object',$object); * $object2=$cache->get('object'); * </code> * * You can configure TMemCache two different ways. If you only need one memcache server * you may use the method as follows. * <code> * <module id="cache" class="System.Caching.TMemCache" Host="localhost" Port="11211" /> * </code> * * If you want a more complex configuration, you may use the method as follows. * <code> * <module id="cache" classs="System.Caching.TMemCache"> * <server Host="localhost" Port="11211" Weight="1" Timeout="300" RetryInterval="15" /> * <server Host="anotherhost" Port="11211" Weight="1" Timeout="300" RetryInterval="15" /> * </module> * </code> * * If loaded, TMemCache will register itself with {@link TApplication} as the * cache module. It can be accessed via {@link TApplication::getCache()}. * * TMemCache may be configured in application configuration file as follows * <code> * <module id="cache" class="System.Caching.TMemCache" Host="localhost" Port="11211" /> * </code> * where {@link getHost Host} and {@link getPort Port} are configurable properties * of TMemCache. * * Automatic compression of values may be used (using zlib extension) by setting {@link getThreshold Threshold} and {@link getMinSavings MinSavings} properties. * NB : MemCache server(s) must be restarted to apply settings. Require (PECL memcache >= 2.0.0). * * @author Qiang Xue <qiang.xue@gmail.com> * @version $Id$ * @package System.Caching * @since 3.0 */ class TMemCache extends TCache { /** * @var boolean if the module is initialized */ private $_initialized=false; /** * @var Memcache the Memcache instance */ private $_cache=null; /** * @var string a unique prefix used to identify this cache instance from the others */ private $_prefix=null; /** * @var string host name of the memcache server */ private $_host='localhost'; /** * @var integer the port number of the memcache server */ private $_port=11211; /** * @var boolean controls the use of a persistent connection. Default to true. */ private $_persistence = true; /** * @var integer 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. */ private $_weight = 1; private $_timeout = 360; private $_retryInterval = 15; /** * @var integer Controls the minimum value length before attempting to compress automatically. */ private $_threshold=0; /** * @var float Specifies the minimum amount of savings to actually store the value compressed. The supplied value must be between 0 and 1. Default value is 0.2 giving a minimum 20% compression savings. */ private $_minSavings=0.0; private $_status = true; private $_failureCallback = null; /** * @var array list of servers available */ private $_servers=array(); /** * Destructor. * Disconnect the memcache server. */ public function __destruct() { if($this->_cache!==null) $this->_cache->close(); } /** * Initializes this module. * This method is required by the IModule interface. It makes sure that * UniquePrefix has been set, creates a Memcache instance and connects * to the memcache server. * @param TApplication Prado application, can be null * @param TXmlElement configuration for this module, can be null * @throws TConfigurationException if memcache extension is not installed or memcache sever connection fails */ public function init($config) { if(!extension_loaded('memcache')) throw new TConfigurationException('memcache_extension_required'); $this->_cache=new Memcache; $this->loadConfig($config); if(count($this->_servers)) { foreach($this->_servers as $server) { Prado::trace('Adding server '.$server['Host'].' from serverlist', 'System.Caching.TMemCache'); if($this->_cache->addServer($server['Host'],$server['Port'],$server['Persistent'], $server['Weight'],$server['Timeout'],$server['RetryInterval'])===false) throw new TConfigurationException('memcache_connection_failed',$server['Host'],$server['Port']); } } else { Prado::trace('Adding server '.$this->_host, 'System.Caching.TMemCache'); if($this->_cache->addServer($this->_host,$this->_port)===false) throw new TConfigurationException('memcache_connection_failed',$this->_host,$this->_port); } if($this->_threshold!==0) $this->_cache->setCompressThreshold($this->_threshold,$this->_minSavings); $this->_initialized=true; parent::init($config); } /** * Loads configuration from an XML element * @param TXmlElement configuration node * @throws TConfigurationException if log route class or type is not specified */ private function loadConfig($xml) { if($xml instanceof TXmlElement) { foreach($xml->getElementsByTagName('server') as $serverConfig) { $properties=$serverConfig->getAttributes(); if(($host=$properties->remove('Host'))===null) throw new TConfigurationException('memcache_serverhost_required'); if(($port=$properties->remove('Port'))===null) throw new TConfigurationException('memcache_serverport_required'); if(!is_numeric($port)) throw new TConfigurationException('memcache_serverport_invalid'); $server = array('Host'=>$host,'Port'=>$port,'Weight'=>1,'Timeout'=>1800,'RetryInterval'=>15,'Persistent'=>true); $checks = array( 'Weight'=>'memcache_serverweight_invalid', 'Timeout'=>'memcache_servertimeout_invalid', 'RetryInterval'=>'memcach_serverretryinterval_invalid' ); foreach($checks as $property=>$exception) { $value=$properties->remove($property); if($value!==null && is_numeric($value)) $server[$property]=$value; else if($value!==null) throw new TConfigurationException($exception); } $server['Persistent']= TPropertyValue::ensureBoolean($properties->remove('Persistent')); $this->_servers[]=$server; } } } /** * @return string host name of the memcache server */ public function getHost() { return $this->_host; } /** * @param string host name of the memcache server * @throws TInvalidOperationException if the module is already initialized */ public function setHost($value) { if($this->_initialized) throw new TInvalidOperationException('memcache_host_unchangeable'); else $this->_host=$value; } /** * @return integer port number of the memcache server */ public function getPort() { return $this->_port; } /** * @param integer port number of the memcache server * @throws TInvalidOperationException if the module is already initialized */ public function setPort($value) { if($this->_initialized) throw new TInvalidOperationException('memcache_port_unchangeable'); else $this->_port=TPropertyValue::ensureInteger($value); } /** * @return integer minimum value length before attempting to compress */ public function getThreshold() { return $this->_threshold; } /** * @param integer minimum value length before attempting to compress * @throws TInvalidOperationException if the module is already initialized */ public function setThreshold($value) { if($this->_initialized) throw new TInvalidOperationException('memcache_threshold_unchangeable'); else $this->_threshold=TPropertyValue::ensureInteger($value); } /** * @return float minimum amount of savings to actually store the value compressed */ public function getMinSavings() { return $this->_minSavings; } /** * @param float minimum amount of savings to actually store the value compressed * @throws TInvalidOperationException if the module is already initialized */ public function setMinSavings($value) { if($this->_initialized) throw new TInvalidOperationException('memcache_min_savings_unchangeable'); else $this->_minSavings=TPropertyValue::ensureFloat($value); } /** * Retrieves a value from cache with a specified key. * This is the implementation of the method declared in the parent class. * @param string a unique key identifying the cached value * @return string the value stored in cache, false if the value is not in the cache or expired. */ protected function getValue($key) { return $this->_cache->get($key); } /** * Stores a value identified by a key in cache. * This is the implementation of the method declared in the parent class. * * @param string the key identifying the value to be cached * @param string the value to be cached * @param integer the number of seconds in which the cached value will expire. 0 means never expire. * @return boolean true if the value is successfully stored into cache, false otherwise */ protected function setValue($key,$value,$expire) { return $this->_cache->set($key,$value,0,$expire); } /** * Stores a value identified by a key into cache if the cache does not contain this key. * This is the implementation of the method declared in the parent class. * * @param string the key identifying the value to be cached * @param string the value to be cached * @param integer the number of seconds in which the cached value will expire. 0 means never expire. * @return boolean true if the value is successfully stored into cache, false otherwise */ protected function addValue($key,$value,$expire) { return $this->_cache->add($key,$value,0,$expire); } /** * Deletes a value with the specified key from cache * This is the implementation of the method declared in the parent class. * @param string the key of the value to be deleted * @return boolean if no error happens during deletion */ protected function deleteValue($key) { return $this->_cache->delete($key); } /** * Deletes all values from cache. * Be careful of performing this operation if the cache is shared by multiple applications. */ public function flush() { return $this->_cache->flush(); } }