CStatePersister
| Package | system.base |
|---|---|
| Inheritance | class CStatePersister » CApplicationComponent » CComponent |
| Implements | IApplicationComponent, IStatePersister |
| Since | 1.0 |
| Version | $Id: CStatePersister.php 3515 2011-12-28 12:29:24Z mdomba $ |
| Source Code | framework/base/CStatePersister.php |
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 runtime path. You may change the location by setting the stateFile property.
To retrieve the data from CStatePersister, call load(). To save the data, call save().
Comparison among state persister, session and cache is as follows:
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 CApplication::getStatePersister(). page state persistent method based on cache.
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 runtime path. You may change the location by setting the stateFile property.
To retrieve the data from CStatePersister, call load(). To save the data, call 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 CApplication::getStatePersister(). page state persistent method based on cache.
Public Properties
| Property | Type | Description | Defined By |
|---|---|---|---|
| behaviors | array | the behaviors that should be attached to this component. | CApplicationComponent |
| cacheID | string | the ID of the cache application component that is used to cache the state values. | CStatePersister |
| isInitialized | boolean | Checks if this application component bas been initialized. | CApplicationComponent |
| stateFile | string | the file path storing the state data. | CStatePersister |
Public Methods
| Method | Description | Defined By |
|---|---|---|
| __call() | Calls the named method which is not a class method. | CComponent |
| __get() | Returns a property value, an event handler list or a behavior based on its name. | CComponent |
| __isset() | Checks if a property value is null. | CComponent |
| __set() | Sets value of a component property. | CComponent |
| __unset() | Sets a component property to be null. | CComponent |
| asa() | Returns the named behavior object. | CComponent |
| attachBehavior() | Attaches a behavior to this component. | CComponent |
| attachBehaviors() | Attaches a list of behaviors to the component. | CComponent |
| attachEventHandler() | Attaches an event handler to an event. | CComponent |
| canGetProperty() | Determines whether a property can be read. | CComponent |
| canSetProperty() | Determines whether a property can be set. | CComponent |
| detachBehavior() | Detaches a behavior from the component. | CComponent |
| detachBehaviors() | Detaches all behaviors from the component. | CComponent |
| detachEventHandler() | Detaches an existing event handler. | CComponent |
| disableBehavior() | Disables an attached behavior. | CComponent |
| disableBehaviors() | Disables all behaviors attached to this component. | CComponent |
| enableBehavior() | Enables an attached behavior. | CComponent |
| enableBehaviors() | Enables all behaviors attached to this component. | CComponent |
| evaluateExpression() | Evaluates a PHP expression or callback under the context of this component. | CComponent |
| getEventHandlers() | Returns the list of attached event handlers for an event. | CComponent |
| getIsInitialized() | Checks if this application component bas been initialized. | CApplicationComponent |
| hasEvent() | Determines whether an event is defined. | CComponent |
| hasEventHandler() | Checks whether the named event has attached handlers. | CComponent |
| hasProperty() | Determines whether a property is defined. | CComponent |
| init() | Initializes the component. | CStatePersister |
| load() | Loads state data from persistent storage. | CStatePersister |
| raiseEvent() | Raises an event. | CComponent |
| save() | Saves application state in persistent storage. | CStatePersister |
Property Details
cacheID
property
public string $cacheID;
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.
stateFile
property
public string $stateFile;
the file path storing the state data. Make sure the directory containing the file exists and is writable by the Web server process. If using relative path, also make sure the path is correct.
Method Details
init()
method
|
public void init()
|
Source Code: framework/base/CStatePersister.php#63 (show)
public function init()
{
parent::init();
if($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)));
}
Initializes the component. This method overrides the parent implementation by making sure stateFile contains valid value.
load()
method
|
public mixed load()
| ||
| {return} | mixed | state data. Null if no state data available. |
Source Code: framework/base/CStatePersister.php#78 (show)
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);
else if(($content=@file_get_contents($stateFile))!==false)
{
$cache->set($cacheKey,$content,0,new CFileCacheDependency($stateFile));
return unserialize($content);
}
else
return null;
}
else if(($content=@file_get_contents($stateFile))!==false)
return unserialize($content);
else
return null;
}
Loads state data from persistent storage.
save()
method
|
public void save(mixed $state)
| ||
| $state | mixed | state data (must be serializable). |
Source Code: framework/base/CStatePersister.php#104 (show)
public function save($state)
{
file_put_contents($this->stateFile,serialize($state),LOCK_EX);
}
Saves application state in persistent storage.