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Diffstat (limited to 'framework/Data/TMemCache.php')
| -rw-r--r-- | framework/Data/TMemCache.php | 268 |
1 files changed, 268 insertions, 0 deletions
diff --git a/framework/Data/TMemCache.php b/framework/Data/TMemCache.php new file mode 100644 index 00000000..73eec99f --- /dev/null +++ b/framework/Data/TMemCache.php @@ -0,0 +1,268 @@ +<?php
+/**
+ * TMemCache class file
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright © 2005 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Revision: $ $Date: $
+ * @package System.Data
+ */
+
+/**
+ * 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 replace} : store the value only if cache has 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>
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $ $Date: $
+ * @package System.Data
+ * @since 3.0
+ */
+class TMemCache extends TComponent implements IModule, ICache
+{
+ /**
+ * @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 string ID of this module
+ */
+ private $_id='';
+
+ /**
+ * Destructor.
+ * Disconnect the memcache server.
+ */
+ public function __destruct()
+ {
+ if($this->_cache!==null)
+ $this->_cache->close();
+ parent::__destruct();
+ }
+
+ /**
+ * Initializes this module.
+ * This method is required by the IModule interface. It makes sure that
+ * UniquePrefix has been set, creates a Memcache instance and connects
+ * to the memcache server.
+ * @param IApplication Prado application, can be null
+ * @param TXmlElement configuration for this module, can be null
+ * @throws TConfigurationException if memcache extension is not installed or memcache sever connection fails
+ */
+ public function init($application,$config)
+ {
+ if(!extension_loaded('memcache'))
+ throw new TConfigurationException('memcache_extension_required');
+ $this->_cache=new Memcache;
+ if($this->_cache->connect($this->_host,$this->_port)===false)
+ throw new TInvalidConfigurationException('memcache_connection_failed');
+ if($application instanceof IApplication)
+ $this->_prefix=$application->getUniqueID();
+ $this->_initialized=true;
+ }
+
+ /**
+ * @return string id of this module
+ */
+ public function getID()
+ {
+ return $this->_id;
+ }
+
+ /**
+ * @param string id of this module
+ */
+ public function setID($value)
+ {
+ $this->_id=$value;
+ }
+
+ /**
+ * @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);
+ }
+
+ /**
+ * Retrieves a value from cache with a specified key.
+ * @return mixed the value stored in cache, false if the value is not in the cache or expired.
+ */
+ public function get($key)
+ {
+ return $this->_cache->get($this->generateUniqueKey($key));
+ }
+
+ /**
+ * Stores a value identified by a key into cache.
+ * If the cache already contains such a key, the existing value and
+ * expiration time will be replaced with the new ones.
+ *
+ * Note, avoid using this method whenever possible. Database insertion is
+ * very expensive. Try using {@link add} instead, which will not store the value
+ * if the key is already in cache.
+ *
+ * @param string the key identifying the value to be cached
+ * @param mixed the value to be cached
+ * @param integer the expiration time of the value,
+ * 0 means never expire,
+ * a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+ * a number greater than 60 means a UNIX timestamp after which the value will expire.
+ * @return boolean true if the value is successfully stored into cache, false otherwise
+ */
+ public function set($key,$value,$expire=0)
+ {
+ return $this->_cache->set($this->generateUniqueKey($key),$value,0,$expire);
+ }
+
+ /**
+ * Stores a value identified by a key into cache if the cache does not contain this key.
+ * Nothing will be done if the cache already contains the key.
+ * @param string the key identifying the value to be cached
+ * @param mixed the value to be cached
+ * @param integer the expiration time of the value,
+ * 0 means never expire,
+ * a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+ * a number greater than 60 means a UNIX timestamp after which the value will expire.
+ * @return boolean true if the value is successfully stored into cache, false otherwise
+ */
+ public function add($key,$value,$expiry=0)
+ {
+ return $this->_cache->add($this->generateUniqueKey($key),$value,0,$expire);
+ }
+
+ /**
+ * Stores a value identified by a key into cache only if the cache contains this key.
+ * The existing value and expiration time will be overwritten with the new ones.
+ * @param string the key identifying the value to be cached
+ * @param mixed the value to be cached
+ * @param integer the expiration time of the value,
+ * 0 means never expire,
+ * a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+ * a number greater than 60 means a UNIX timestamp after which the value will expire.
+ * @return boolean true if the value is successfully stored into cache, false otherwise
+ */
+ public function replace($key,$value,$expiry=0)
+ {
+ return $this->_cache->replace($this->generateUniqueKey($key),$value,0,$expire);
+ }
+
+ /**
+ * Deletes a value with the specified key from cache
+ * @param string the key of the value to be deleted
+ * @return boolean if no error happens during deletion
+ */
+ public function delete($key)
+ {
+ return $this->_cache->delete($this->generateUniqueKey($key));
+ }
+
+ /**
+ * Deletes all values from cache.
+ * Be careful of performing this operation if the cache is shared by multiple applications.
+ */
+ public function flush()
+ {
+ return $this->_cache->flush();
+ }
+
+ /**
+ * Generates a unique key based on a given user key.
+ * This method generates a unique key with the memcache.
+ * The key is made unique by prefixing with a unique string that is supposed
+ * to be unique among applications using the same memcache.
+ * @param string user key
+ * @param string a unique key
+ */
+ protected function generateUniqueKey($key)
+ {
+ return md5($this->_prefix.$key);
+ }
+}
+
+?>
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