1 files changed, 323 insertions, 0 deletions
diff --git a/framework/Caching/TDbCache.php b/framework/Caching/TDbCache.php
new file mode 100644
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+++ b/framework/Caching/TDbCache.php
@@ -0,0 +1,323 @@
+<?php
+/**
+ * TDbCache class file
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright &copy; 2005-2007 PradoSoft
+ * @license http://www.pradosoft.com/license/
+ * @version $Id$
+ * @package System.Caching
+ */
+
+Prado::using('System.Data.TDbConnection');
+
+/**
+ * TDbCache class
+ *
+ * TDbCache implements a cache application module by storing cached data in a database.
+ *
+ * TDbCache relies on {@link http://www.php.net/manual/en/ref.pdo.php PDO} to retrieve
+ * data from databases. In order to use TDbCache, you need to enable the PDO extension
+ * as well as the corresponding PDO DB driver. For example, to use SQLite database
+ * to store cached data, you need both php_pdo and php_pdo_sqlite extensions.
+ *
+ * By default, TDbCache creates and uses an SQLite database under the application
+ * runtime directory. You may change this default setting by specifying the following
+ * properties:
+ * - {@link setConnectionString ConnectionString}
+ * - {@link setUsername Username}
+ * - {@link setPassword Pasword}
+ *
+ * The cached data is stored in a table in the specified database.
+ * By default, the name of the table is called 'pradocache'. If the table does not
+ * exist in the database, it will be automatically created with the following structure:
+ * (key CHAR(128) PRIMARY KEY, value BLOB, expire INT)
+ *
+ * If you want to change the cache table name, or if you want to create the table by yourself,
+ * you may set {@link setCacheTableName CacheTableName} and {@link setAutoCreateCacheTable AutoCreateCacheTableName} properties.
+ *
+ * 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 by
+ * the number of seconds. 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.
+ *
+ * Do not use the same database file for multiple applications using TDbCache.
+ * Also note, cache is shared by all user sessions of an application.
+ *
+ * To use this module, the sqlite PHP extension must be loaded. Note, Sqlite extension
+ * is no longer loaded by default since PHP 5.1.
+ *
+ * Some usage examples of TDbCache are as follows,
+ * <code>
+ * $cache=new TDbCache;  // TDbCache may also be loaded as a Prado application module
+ * $cache->init(null);
+ * $cache->add('object',$object);
+ * $object2=$cache->get('object');
+ * </code>
+ *
+ * If loaded, TDbCache will register itself with {@link TApplication} as the
+ * cache module. It can be accessed via {@link TApplication::getCache()}.
+ *
+ * TDbCache may be configured in application configuration file as follows
+ * <code>
+ * <module id="cache" class="System.Caching.TDbCache" />
+ * </code>
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Id$
+ * @package System.Caching
+ * @since 3.1.0
+ */
+class TDbCache extends TCache
+{
+	/**
+	 * @var TDbConnection the DB connection instance
+	 */
+	private $_db;
+	/**
+	 * @var string name of the DB cache table
+	 */
+	private $_cacheTable='pradocache';
+	/**
+	 * @var boolean whether the cache DB table should be created automatically
+	 */
+	private $_autoCreate=true;
+
+	/**
+	 * Destructor.
+	 * Disconnect the db connection.
+	 */
+	public function __destruct()
+	{
+		if($this->_db!==null)
+			$this->_db->setActive(false);
+	}
+
+	/**
+	 * Initializes this module.
+	 * This method is required by the IModule interface. It checks if the DbFile
+	 * property is set, and creates a SQLiteDatabase instance for it.
+	 * The database or the cache table does not exist, they will be created.
+	 * Expired values are also deleted.
+	 * @param TXmlElement configuration for this module, can be null
+	 * @throws TConfigurationException if sqlite extension is not installed,
+	 *         DbFile is set invalid, or any error happens during creating database or cache table.
+	 */
+	public function init($config)
+	{
+		$db=$this->getDbConnection();
+		if($db->getConnectionString()==='')
+		{
+			// default to SQLite3 database
+			$dbFile=$this->getApplication()->getRuntimePath().'/sqlite3.cache';
+			$db->setConnectionString('sqlite:'.$dbFile);
+		}
+
+		$db->setActive(true);
+
+		$sql='DELETE FROM '.$this->_cacheTable.' WHERE expire<>0 AND expire<'.time();
+		try
+		{
+			$db->createCommand($sql)->execute();
+		}
+		catch(Exception $e)
+		{
+			// DB table not exists
+			if($this->_autoCreate)
+			{
+				$sql='CREATE TABLE '.$this->_cacheTable.' (key CHAR(128) PRIMARY KEY, value BLOB, expire INT)';
+				$db->createCommand($sql)->execute();
+			}
+			else
+				throw TConfigurationException('pdocache_cachetable_inexistent',$this->_cacheTable);
+		}
+
+		parent::init($config);
+	}
+
+	/**
+	 * @return TDbConnection the DB connection instance
+	 */
+	public function getDbConnection()
+	{
+		if($this->_db===null)
+			$this->_db=new TDbConnection;
+		return $this->_db;
+	}
+
+	/**
+	 * @return string The Data Source Name, or DSN, contains the information required to connect to the database.
+	 */
+	public function getConnectionString()
+	{
+		return $this->getDbConnection()->getConnectionString();
+	}
+
+	/**
+	 * @param string The Data Source Name, or DSN, contains the information required to connect to the database.
+	 * @see http://www.php.net/manual/en/function.pdo-construct.php
+	 */
+	public function setConnectionString($value)
+	{
+		$this->getDbConnection()->getConnectionString($value);
+	}
+
+	/**
+	 * @return string the username for establishing DB connection. Defaults to empty string.
+	 */
+	public function getUsername()
+	{
+		return $this->getDbConnection()->getUsername();
+	}
+
+	/**
+	 * @param string the username for establishing DB connection
+	 */
+	public function setUsername($value)
+	{
+		$this->getDbConnection()->setUsername($value);
+	}
+
+	/**
+	 * @return string the password for establishing DB connection. Defaults to empty string.
+	 */
+	public function getPassword()
+	{
+		return $this->getDbConnection()->getPassword();
+	}
+
+	/**
+	 * @param string the password for establishing DB connection
+	 */
+	public function setPassword($value)
+	{
+		$this->getDbConnection()->setPassword($value);
+	}
+
+	/**
+	 * @return string the name of the DB table to store cache content. Defaults to 'pradocache'.
+	 * @see setAutoCreateCacheTable
+	 */
+	public function getCacheTableName()
+	{
+		return $this->_cacheTable;
+	}
+
+	/**
+	 * Sets the name of the DB table to store cache content.
+	 * Note, if {@link setAutoCreateCacheTable AutoCreateCacheTable} is false
+	 * and you want to create the DB table manually by yourself,
+	 * you need to make sure the DB table is of the following structure:
+	 * (key CHAR(128) PRIMARY KEY, value BLOB, expire INT)
+	 * @param string the name of the DB table to store cache content
+	 * @see setAutoCreateCacheTable
+	 */
+	public function setCacheTableName($value)
+	{
+		$this->_cacheTable=$value;
+	}
+
+	/**
+	 * @return boolean whether the cache DB table should be automatically created if not exists. Defaults to true.
+	 * @see setAutoCreateCacheTable
+	 */
+	public function getAutoCreateCacheTable()
+	{
+		return $this->_autoCreate;
+	}
+
+	/**
+	 * @param boolean whether the cache DB table should be automatically created if not exists.
+	 * @see setCacheTableName
+	 */
+	public function setAutoCreateCacheTable($value)
+	{
+		$this->_autoCreate=TPropertyValue::ensureBoolean($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)
+	{
+		$sql='SELECT value FROM '.$this->_cacheTable.' WHERE key=\''.$key.'\' AND (expire=0 OR expire>'.time().')';
+		return $this->_db->createCommand($sql)->queryScalar();
+	}
+
+	/**
+	 * 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)
+	{
+		$this->deleteValue($key);
+		return $this->addValue($key,$value,$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)
+	{
+		$sql="INSERT INTO {$this->_cacheTable} (key,value,expire) VALUES('$key',:value,$expire)";
+		try
+		{
+			$command=$this->_db->createCommand($sql);
+			$command->bindValue(':value',$value,PDO::PARAM_LOB);
+			$command->execute();
+			return true;
+		}
+		catch(Exception $e)
+		{
+			return false;
+		}
+	}
+
+	/**
+	 * Deletes a value with the specified key from cache
+	 * This is the implementation of the method declared in the parent class.
+	 * @param string the key of the value to be deleted
+	 * @return boolean if no error happens during deletion
+	 */
+	protected function deleteValue($key)
+	{
+		$this->_db->createCommand("DELETE FROM {$this->_cacheTable} WHERE key='$key'")->execute();
+		return true;
+	}
+
+	/**
+	 * Deletes all values from cache.
+	 * Be careful of performing this operation if the cache is shared by multiple applications.
+	 */
+	public function flush()
+	{
+		$this->_db->createCommand("DELETE FROM {$this->_cacheTable}")->execute();
+		return true;
+	}
+}
+
+?>
+\ No newline at end of file