* @link http://www.yiiframework.com/
* @copyright 2008-2013 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CStatePersister implements a file-based persistent data storage.
*
* It can be used to keep data available through multiple requests and sessions.
*
* By default, CStatePersister stores data in a file named 'state.bin' that is located
* under the application {@link CApplication::getRuntimePath runtime path}.
* You may change the location by setting the {@link stateFile} property.
*
* To retrieve the data from CStatePersister, call {@link load()}. To save the data,
* call {@link save()}.
*
* Comparison among state persister, session and cache is as follows:
*
* - session: data persisting within a single user session.
* - state persister: data persisting through all requests/sessions (e.g. hit counter).
* - cache: volatile and fast storage. It may be used as storage medium for session or state persister.
*
*
* Since server resource is often limited, be cautious if you plan to use CStatePersister
* to store large amount of data. You should also consider using database-based persister
* to improve the throughput.
*
* CStatePersister is a core application component used to store global application state.
* It may be accessed via {@link CApplication::getStatePersister()}.
* page state persistent method based on cache.
*
* @author Qiang Xue
* @package system.base
* @since 1.0
*/
class CStatePersister extends CApplicationComponent implements IStatePersister
{
/**
* @var string the file path storing the state data. Make sure the directory containing
* the file exists and is writable by the Web server process. If using relative path, also
* make sure the path is correct.
*/
public $stateFile;
/**
* @var string the ID of the cache application component that is used to cache the state values.
* Defaults to 'cache' which refers to the primary cache application component.
* Set this property to false if you want to disable caching state values.
*/
public $cacheID='cache';
/**
* Initializes the component.
* This method overrides the parent implementation by making sure {@link stateFile}
* contains valid value.
*/
public function init()
{
parent::init();
if($this->stateFile===null)
$this->stateFile=Yii::app()->getRuntimePath().DIRECTORY_SEPARATOR.'state.bin';
$dir=dirname($this->stateFile);
if(!is_dir($dir) || !is_writable($dir))
throw new CException(Yii::t('yii','Unable to create application state file "{file}". Make sure the directory containing the file exists and is writable by the Web server process.',
array('{file}'=>$this->stateFile)));
}
/**
* Loads state data from persistent storage.
* @return mixed state data. Null if no state data available.
*/
public function load()
{
$stateFile=$this->stateFile;
if($this->cacheID!==false && ($cache=Yii::app()->getComponent($this->cacheID))!==null)
{
$cacheKey='Yii.CStatePersister.'.$stateFile;
if(($value=$cache->get($cacheKey))!==false)
return unserialize($value);
elseif(($content=@file_get_contents($stateFile))!==false)
{
$cache->set($cacheKey,$content,0,new CFileCacheDependency($stateFile));
return unserialize($content);
}
else
return null;
}
elseif(($content=@file_get_contents($stateFile))!==false)
return unserialize($content);
else
return null;
}
/**
* Saves application state in persistent storage.
* @param mixed $state state data (must be serializable).
*/
public function save($state)
{
file_put_contents($this->stateFile,serialize($state),LOCK_EX);
}
}