Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

315 lines (295 sloc) 9.774 kb
<?php
/**
* CDbCache class file
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @link http://www.yiiframework.com/
* @copyright Copyright &copy; 2008-2011 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CDbCache implements a cache application component by storing cached data in a database.
*
* CDbCache stores cache data in a DB table named {@link cacheTableName}.
* If the table does not exist, it will be automatically created.
* By setting {@link autoCreateCacheTable} to false, you can also manually create the DB table.
*
* CDbCache relies on {@link http://www.php.net/manual/en/ref.pdo.php PDO} to access database.
* By default, it will use a SQLite3 database under the application runtime directory.
* You can also specify {@link connectionID} so that it makes use of
* a DB application component to access database.
*
* See {@link CCache} manual for common cache operations that are supported by CDbCache.
*
* @property integer $gCProbability The probability (parts per million) that garbage collection (GC) should be performed
* when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
* @property CDbConnection $dbConnection The DB connection instance.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @version $Id$
* @package system.caching
* @since 1.0
*/
class CDbCache extends CCache
{
/**
* @var string the ID of the {@link CDbConnection} application component. If not set,
* a SQLite3 database will be automatically created and used. The SQLite database file
* is <code>protected/runtime/cache-YiiVersion.db</code>.
*/
public $connectionID;
/**
* @var string name of the DB table to store cache content. Defaults to 'YiiCache'.
* Note, if {@link 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:
* <pre>
* (id CHAR(128) PRIMARY KEY, expire INTEGER, value BLOB)
* </pre>
* Note, some DBMS might not support BLOB type. In this case, replace 'BLOB' with a suitable
* binary data type (e.g. LONGBLOB in MySQL, BYTEA in PostgreSQL.)
* @see autoCreateCacheTable
*/
public $cacheTableName='YiiCache';
/**
* @var boolean whether the cache DB table should be created automatically if it does not exist. Defaults to true.
* If you already have the table created, it is recommended you set this property to be false to improve performance.
* @see cacheTableName
*/
public $autoCreateCacheTable=true;
/**
* @var CDbConnection the DB connection instance
*/
private $_db;
private $_gcProbability=100;
private $_gced=false;
/**
* Initializes this application component.
*
* This method is required by the {@link IApplicationComponent} interface.
* It ensures the existence of the cache DB table.
* It also removes expired data items from the cache.
*/
public function init()
{
parent::init();
$db=$this->getDbConnection();
$db->setActive(true);
if($this->autoCreateCacheTable)
{
$sql="DELETE FROM {$this->cacheTableName} WHERE expire>0 AND expire<".time();
try
{
$db->createCommand($sql)->execute();
}
catch(Exception $e)
{
$this->createCacheTable($db,$this->cacheTableName);
}
}
}
/**
* @return integer the probability (parts per million) that garbage collection (GC) should be performed
* when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
*/
public function getGCProbability()
{
return $this->_gcProbability;
}
/**
* @param integer $value the probability (parts per million) that garbage collection (GC) should be performed
* when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
* This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all.
*/
public function setGCProbability($value)
{
$value=(int)$value;
if($value<0)
$value=0;
if($value>1000000)
$value=1000000;
$this->_gcProbability=$value;
}
/**
* Creates the cache DB table.
* @param CDbConnection $db the database connection
* @param string $tableName the name of the table to be created
*/
protected function createCacheTable($db,$tableName)
{
$driver=$db->getDriverName();
if($driver==='mysql')
$blob='LONGBLOB';
else if($driver==='pgsql')
$blob='BYTEA';
else
$blob='BLOB';
$sql=<<<EOD
CREATE TABLE $tableName
(
id CHAR(128) PRIMARY KEY,
expire INTEGER,
value $blob
)
EOD;
$db->createCommand($sql)->execute();
}
/**
* @return CDbConnection the DB connection instance
* @throws CException if {@link connectionID} does not point to a valid application component.
*/
public function getDbConnection()
{
if($this->_db!==null)
return $this->_db;
else if(($id=$this->connectionID)!==null)
{
if(($this->_db=Yii::app()->getComponent($id)) instanceof CDbConnection)
return $this->_db;
else
throw new CException(Yii::t('yii','CDbCache.connectionID "{id}" is invalid. Please make sure it refers to the ID of a CDbConnection application component.',
array('{id}'=>$id)));
}
else
{
$dbFile=Yii::app()->getRuntimePath().DIRECTORY_SEPARATOR.'cache-'.Yii::getVersion().'.db';
return $this->_db=new CDbConnection('sqlite:'.$dbFile);
}
}
/**
* Sets the DB connection used by the cache component.
* @param CDbConnection $value the DB connection instance
* @since 1.1.5
*/
public function setDbConnection($value)
{
$this->_db=$value;
}
/**
* Retrieves a value from cache with a specified key.
* This is the implementation of the method declared in the parent class.
* @param string $key a unique key identifying the cached value
* @return string the value stored in cache, false if the value is not in the cache or expired.
*/
protected function getValue($key)
{
$time=time();
$sql="SELECT value FROM {$this->cacheTableName} WHERE id='$key' AND (expire=0 OR expire>$time)";
$db=$this->getDbConnection();
if($db->queryCachingDuration>0)
{
$duration=$db->queryCachingDuration;
$db->queryCachingDuration=0;
$result=$db->createCommand($sql)->queryScalar();
$db->queryCachingDuration=$duration;
return $result;
}
else
return $db->createCommand($sql)->queryScalar();
}
/**
* Retrieves multiple values from cache with the specified keys.
* @param array $keys a list of keys identifying the cached values
* @return array a list of cached values indexed by the keys
*/
protected function getValues($keys)
{
if(empty($keys))
return array();
$ids=implode("','",$keys);
$time=time();
$sql="SELECT id, value FROM {$this->cacheTableName} WHERE id IN ('$ids') AND (expire=0 OR expire>$time)";
$db=$this->getDbConnection();
if($db->queryCachingDuration>0)
{
$duration=$db->queryCachingDuration;
$db->queryCachingDuration=0;
$rows=$db->createCommand($sql)->queryAll();
$db->queryCachingDuration=$duration;
}
else
$rows=$db->createCommand($sql)->queryAll();
$results=array();
foreach($keys as $key)
$results[$key]=false;
foreach($rows as $row)
$results[$row['id']]=$row['value'];
return $results;
}
/**
* Stores a value identified by a key in cache.
* This is the implementation of the method declared in the parent class.
*
* @param string $key the key identifying the value to be cached
* @param string $value the value to be cached
* @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
* @return boolean true if the value is successfully stored into cache, false otherwise
*/
protected function setValue($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 $key the key identifying the value to be cached
* @param string $value the value to be cached
* @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
* @return boolean true if the value is successfully stored into cache, false otherwise
*/
protected function addValue($key,$value,$expire)
{
if(!$this->_gced && mt_rand(0,1000000)<$this->_gcProbability)
{
$this->gc();
$this->_gced=true;
}
if($expire>0)
$expire+=time();
else
$expire=0;
$sql="INSERT INTO {$this->cacheTableName} (id,expire,value) VALUES ('$key',$expire,:value)";
try
{
$command=$this->getDbConnection()->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 $key the key of the value to be deleted
* @return boolean if no error happens during deletion
*/
protected function deleteValue($key)
{
$sql="DELETE FROM {$this->cacheTableName} WHERE id='$key'";
$this->getDbConnection()->createCommand($sql)->execute();
return true;
}
/**
* Removes the expired data values.
*/
protected function gc()
{
$this->getDbConnection()->createCommand("DELETE FROM {$this->cacheTableName} WHERE expire>0 AND expire<".time())->execute();
}
/**
* Deletes all values from cache.
* This is the implementation of the method declared in the parent class.
* @return boolean whether the flush operation was successful.
* @since 1.1.5
*/
protected function flushValues()
{
$this->getDbConnection()->createCommand("DELETE FROM {$this->cacheTableName}")->execute();
return true;
}
}
Jump to Line
Something went wrong with that request. Please try again.