From 0aa6313662914dcead8adacf68bec3398c2e0dc7 Mon Sep 17 00:00:00 2001
From: xue <>
Date: Fri, 23 Feb 2007 14:36:02 +0000
Subject: Added TDbCache.
---
framework/Caching/TPdoCache.php | 323 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 323 insertions(+)
create mode 100644 framework/Caching/TPdoCache.php
(limited to 'framework/Caching/TPdoCache.php')
diff --git a/framework/Caching/TPdoCache.php b/framework/Caching/TPdoCache.php
new file mode 100644
index 00000000..78fc6849
--- /dev/null
+++ b/framework/Caching/TPdoCache.php
@@ -0,0 +1,323 @@
+
+ * @link http://www.pradosoft.com/
+ * @copyright Copyright © 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,
+ *
+ * $cache=new TDbCache; // TDbCache may also be loaded as a Prado application module
+ * $cache->init(null);
+ * $cache->add('object',$object);
+ * $object2=$cache->get('object');
+ *
+ *
+ * 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
+ *
+ *
+ *
+ *
+ * @author Qiang Xue
+ * @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
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