1 files changed, 265 insertions, 0 deletions
diff --git a/framework/Caching/TSqliteCache.php b/framework/Caching/TSqliteCache.php
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+++ b/framework/Caching/TSqliteCache.php
@@ -0,0 +1,265 @@
+<?php
+/**
+ * TSqliteCache 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.Caching
+ */
+
+/**
+ * TSqliteCache class
+ *
+ * TSqliteCache implements a cache application module based on SQLite database.
+ *
+ * The database file is specified by the {@link setDbFile DbFile} property.
+ * If not set, the database file will be created under the system state path.
+ * If the specified database file does not exist, it will be created automatically.
+ * Make sure the directory containing the specified DB file and the file itself is
+ * writable by the Web server process.
+ *
+ * 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.
+ *
+ * Do not use the same database file for multiple applications using TSqliteCache.
+ * Also note, cache is shared by all user sessions of an application.
+ *
+ * To use this module, the sqlite PHP extension must be loaded. Sqlite extension
+ * is no longer loaded by default since PHP 5.1.
+ *
+ * Some usage examples of TSqliteCache are as follows,
+ * <code>
+ * $cache=new TSqliteCache;  // TSqliteCache may also be loaded as a Prado application module
+ * $cache->setDbFile($dbFilePath);
+ * $cache->init(null);
+ * $cache->add('object',$object);
+ * $object2=$cache->get('object');
+ * </code>
+ *
+ * If loaded, TSqliteCache 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
+ * <module id="cache" type="System.Data.TSqliteCache" DbFile="Application.Data.site" />
+ * where {@link getDbFile DbFile} is a property specifying the location of the
+ * SQLite DB file (in the namespace format).
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @version $Revision: $  $Date: $
+ * @package System.Caching
+ * @since 3.0
+ */
+class TSqliteCache extends TModule implements ICache
+{
+	/**
+	 * name of the table storing cache data
+	 */
+	const CACHE_TABLE='cache';
+	/**
+	 * extension of the db file name
+	 */
+	const DB_FILE_EXT='.db';
+	/**
+	 * maximum number of seconds specified as expire
+	 */
+	const EXPIRE_LIMIT=2592000;  // 30 days
+
+	/**
+	 * @var boolean if the module has been initialized
+	 */
+	private $_initialized=false;
+	/**
+	 * @var SQLiteDatabase the sqlite database instance
+	 */
+	private $_db=null;
+	/**
+	 * @var string the database file name
+	 */
+	private $_file=null;
+
+	/**
+	 * Destructor.
+	 * Disconnect the db connection.
+	 */
+	public function __destruct()
+	{
+		$this->_db=null;
+	}
+
+	/**
+	 * Initializes this module.
+	 * This method is required by the IModule interface. It checks if the DbFile
+	 * property is set, and creates a SQLiteDatabase instance for it.
+	 * The database or the cache table does not exist, they will be created.
+	 * Expired values are also deleted.
+	 * @param TXmlElement configuration for this module, can be null
+	 * @throws TConfigurationException if sqlite extension is not installed,
+	 *         DbFile is set invalid, or any error happens during creating database or cache table.
+	 */
+	public function init($config)
+	{
+		if(!function_exists('sqlite_open'))
+			throw new TConfigurationException('sqlitecache_extension_required');
+		if($this->_file===null)
+			$this->_file=$this->getApplication()->getRuntimePath().'/sqlite.cache';
+		$error='';
+		if(($this->_db=new SQLiteDatabase($this->_file,0666,$error))===false)
+			throw new TConfigurationException('sqlitecache_connection_failed',$error);
+		if(($res=$this->_db->query('SELECT * FROM sqlite_master WHERE tbl_name=\''.self::CACHE_TABLE.'\' AND type=\'table\''))!=false)
+		{
+			if($res->numRows()===0)
+			{
+				if($this->_db->query('CREATE TABLE '.self::CACHE_TABLE.' (key CHAR(128) PRIMARY KEY, value BLOB, serialized INT, expire INT)')===false)
+					throw new TConfigurationException('sqlitecache_table_creation_failed',sqlite_error_string(sqlite_last_error()));
+			}
+		}
+		else
+			throw new TConfigurationException('sqlitecache_table_creation_failed',sqlite_error_string(sqlite_last_error()));
+		$this->_db->query('DELETE FROM '.self::CACHE_TABLE.' WHERE expire<>0 AND expire<'.time());
+		$this->_initialized=true;
+		$this->getApplication()->setCache($this);
+	}
+
+	/**
+	 * @return string database file path (in namespace form)
+	 */
+	public function getDbFile()
+	{
+		return $this->_file;
+	}
+
+	/**
+	 * @param string database file path (in namespace form)
+	 * @throws TInvalidOperationException if the module is already initialized
+	 * @throws TConfigurationException if the file is not in proper namespace format
+	 */
+	public function setDbFile($value)
+	{
+		if($this->_initialized)
+			throw new TInvalidOperationException('sqlitecache_dbfile_unchangeable');
+		else if(($this->_file=Prado::getPathOfNamespace($value,self::DB_FILE_EXT))===null)
+			throw new TConfigurationException('sqlitecache_dbfile_invalid',$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)
+	{
+		$sql='SELECT serialized,value FROM '.self::CACHE_TABLE.' WHERE key=\''.md5($key).'\' AND (expire=0 OR expire>'.time().')';
+		if(($ret=$this->_db->query($sql))!=false && ($row=$ret->fetch(SQLITE_ASSOC))!==false)
+			return $row['serialized']?Prado::unserialize($row['value']):$row['value'];
+		else
+			return false;
+	}
+
+	/**
+	 * Stores a value identified by a key into cache.
+	 * If the cache already contains such a key, the existing value and
+	 * expiration time will be replaced with the new ones.
+	 *
+	 * Note, avoid using this method whenever possible. Database insertion is
+	 * very expensive. Try using {@link add} instead, which will not store the value
+	 * if the key is already in cache.
+	 *
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60*60*24*30 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function set($key,$value,$expire=0)
+	{
+		$serialized=is_string($value)?0:1;
+		$value1=sqlite_escape_string($serialized?Prado::serialize($value):$value);
+		if($expire && $expire<=self::EXPIRE_LIMIT)
+			$expire=time()+$expire;
+		$sql='REPLACE INTO '.self::CACHE_TABLE.' VALUES(\''.md5($key).'\',\''.$value1.'\','.$serialized.','.$expire.')';
+		return $this->_db->query($sql)!==false;
+	}
+
+	/**
+	 * 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*60*24*30 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,$expire=0)
+	{
+		$serialized=is_string($value)?0:1;
+		$value1=sqlite_escape_string($serialized?Prado::serialize($value):$value);
+		if($expire && $expire<=self::EXPIRE_LIMIT)
+			$expire=time()+$expire;
+		$sql='INSERT INTO '.self::CACHE_TABLE.' VALUES(\''.md5($key).'\',\''.$value1.'\','.$serialized.','.$expire.')';
+		return @$this->_db->query($sql)!==false;
+	}
+
+	/**
+	 * Stores a value identified by a key into cache only if the cache contains this key.
+	 * The existing value and expiration time will be overwritten with the new ones.
+	 * @param string the key identifying the value to be cached
+	 * @param mixed the value to be cached
+	 * @param integer the expiration time of the value,
+	 *        0 means never expire,
+	 *        a number less or equal than 60*60*24*30 means the number of seconds that the value will remain valid.
+	 *        a number greater than 60*60*24*30 means a UNIX timestamp after which the value will expire.
+	 * @return boolean true if the value is successfully stored into cache, false otherwise
+	 */
+	public function replace($key,$value,$expire=0)
+	{
+		$serialized=is_string($value)?0:1;
+		$value1=sqlite_escape_string($serialized?Prado::serialize($value):$value);
+		if($expire && $expire<=self::EXPIRE_LIMIT)
+			$expire=time()+$expire;
+		$sql='UPDATE '.self::CACHE_TABLE.' SET value=\''.$value1.'\', serialized='.$serialized.',expire='.$expire.' WHERE key=\''.md5($key).'\'';
+		$this->_db->query($sql);
+		$ret=$this->_db->query('SELECT serialized FROM '.self::CACHE_TABLE.' WHERE key=\''.md5($key).'\'');
+		return ($ret!=false && $ret->numRows()>0);
+	}
+
+	/**
+	 * Deletes a value with the specified key from cache
+	 * @param string the key of the value to be deleted
+	 * @return boolean if no error happens during deletion
+	 */
+	public function delete($key)
+	{
+		$sql='DELETE FROM '.self::CACHE_TABLE.' WHERE key=\''.md5($key).'\'';
+		return $this->_db->query($sql)!==false;
+	}
+
+	/**
+	 * Deletes all values from cache.
+	 * Be careful of performing this operation if the cache is shared by multiple applications.
+	 */
+	public function flush()
+	{
+		return $this->_db->query('DELETE FROM '.self::CACHE_TABLE)!==false;
+	}
+}
+
+?>
+\ No newline at end of file