Initial import of prado framework

1 files changed, 268 insertions, 0 deletions

diff --git a/framework/Data/TMemCache.php b/framework/Data/TMemCache.php
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+<?php

+/**

+ * TMemCache class file

+ *

+ * @author Qiang Xue <qiang.xue@gmail.com>

+ * @link http://www.pradosoft.com/

+ * @copyright Copyright &copy; 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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