CController.php

<?php
/**
 * CController 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/
 */


/**
 * CController manages a set of actions which deal with the corresponding user requests.
 *
 * Through the actions, CController coordinates the data flow between models and views.
 *
 * When a user requests an action 'XYZ', CController will do one of the following:
 * 1. Method-based action: call method 'actionXYZ' if it exists;
 * 2. Class-based action: create an instance of class 'XYZ' if the class is found in the action class map
 *    (specified via {@link actions()}, and execute the action;
 * 3. Call {@link missingAction()}, which by default will raise a 404 HTTP exception.
 *
 * If the user does not specify an action, CController will run the action specified by
 * {@link defaultAction}, instead.
 *
 * CController may be configured to execute filters before and after running actions.
 * Filters preprocess/postprocess the user request/response and may quit executing actions
 * if needed. They are executed in the order they are specified. If during the execution,
 * any of the filters returns true, the rest filters and the action will no longer get executed.
 *
 * Filters can be individual objects, or methods defined in the controller class.
 * They are specified by overriding {@link filters()} method. The following is an example
 * of the filter specification:
 * <pre>
 * array(
 *     'accessControl - login',
 *     'ajaxOnly + search',
 *     array(
 *         'COutputCache + list',
 *         'duration'=>300,
 *     ),
 * )
 * </pre>
 * The above example declares three filters: accessControl, ajaxOnly, COutputCache. The first two
 * are method-based filters (defined in CController), which refer to filtering methods in the controller class;
 * while the last refers to a object-based filter whose class is 'system.web.widgets.COutputCache' and
 * the 'duration' property is initialized as 300 (s).
 *
 * For method-based filters, a method named 'filterXYZ($filterChain)' in the controller class
 * will be executed, where 'XYZ' stands for the filter name as specified in {@link filters()}.
 * Note, inside the filter method, you must call <code>$filterChain->run()</code> if the action should
 * be executed. Otherwise, the filtering process would stop at this filter.
 *
 * Filters can be specified so that they are executed only when running certain actions.
 * For method-based filters, this is done by using '+' and '-' operators in the filter specification.
 * The '+' operator means the filter runs only when the specified actions are requested;
 * while the '-' operator means the filter runs only when the requested action is not among those actions.
 * For object-based filters, the '+' and '-' operators are following the class name.
 *
 * @property array $actionParams The request parameters to be used for action parameter binding.
 * @property CAction $action The action currently being executed, null if no active action.
 * @property string $id ID of the controller.
 * @property string $uniqueId The controller ID that is prefixed with the module ID (if any).
 * @property string $route The route (module ID, controller ID and action ID) of the current request.
 * @property CWebModule $module The module that this controller belongs to. It returns null
 * if the controller does not belong to any module.
 * @property string $viewPath The directory containing the view files for this controller. Defaults to 'protected/views/ControllerID'.
 * @property CMap $clips The list of clips.
 * @property string $pageTitle The page title. Defaults to the controller name and the action name.
 * @property CStack $cachingStack Stack of {@link COutputCache} objects.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id$
 * @package system.web
 * @since 1.0
 */
class CController extends CBaseController
{
	/**
	 * Name of the hidden field storing persistent page states.
	 */
	const STATE_INPUT_NAME='YII_PAGE_STATE';

	/**
	 * @var mixed the name of the layout to be applied to this controller's views.
	 * Defaults to null, meaning the {@link CWebApplication::layout application layout}
	 * is used. If it is false, no layout will be applied.
	 * Since version 1.0.3, the {@link CWebModule::layout module layout} will be used
	 * if the controller belongs to a module and this layout property is null.
	 */
	public $layout;
	/**
	 * @var string the name of the default action. Defaults to 'index'.
	 */
	public $defaultAction='index';

	private $_id;
	private $_action;
	private $_pageTitle;
	private $_cachingStack;
	private $_clips;
	private $_dynamicOutput;
	private $_pageStates;
	private $_module;


	/**
	 * @param string $id id of this controller
	 * @param CWebModule $module the module that this controller belongs to. This parameter
	 * has been available since version 1.0.3.
	 */
	public function __construct($id,$module=null)
	{
		$this->_id=$id;
		$this->_module=$module;
		$this->attachBehaviors($this->behaviors());
	}

	/**
	 * Initializes the controller.
	 * This method is called by the application before the controller starts to execute.
	 * You may override this method to perform the needed initialization for the controller.
	 * @since 1.0.1
	 */
	public function init()
	{
	}

	/**
	 * Returns the filter configurations.
	 *
	 * By overriding this method, child classes can specify filters to be applied to actions.
	 *
	 * This method returns an array of filter specifications. Each array element specify a single filter.
	 *
	 * For a method-based filter (called inline filter), it is specified as 'FilterName[ +|- Action1, Action2, ...]',
	 * where the '+' ('-') operators describe which actions should be (should not be) applied with the filter.
	 *
	 * For a class-based filter, it is specified as an array like the following:
	 * <pre>
	 * array(
	 *     'FilterClass[ +|- Action1, Action2, ...]',
	 *     'name1'=>'value1',
	 *     'name2'=>'value2',
	 *     ...
	 * )
	 * </pre>
	 * where the name-value pairs will be used to initialize the properties of the filter.
	 *
	 * Note, in order to inherit filters defined in the parent class, a child class needs to
	 * merge the parent filters with child filters using functions like array_merge().
	 *
	 * @return array a list of filter configurations.
	 * @see CFilter
	 */
	public function filters()
	{
		return array();
	}

	/**
	 * Returns a list of external action classes.
	 * Array keys are action IDs, and array values are the corresponding
	 * action class in dot syntax (e.g. 'edit'=>'application.controllers.article.EditArticle')
	 * or arrays representing the configuration of the actions, such as the following,
	 * <pre>
	 * return array(
	 *     'action1'=>'path.to.Action1Class',
	 *     'action2'=>array(
	 *         'class'=>'path.to.Action2Class',
	 *         'property1'=>'value1',
	 *         'property2'=>'value2',
	 *     ),
	 * );
	 * </pre>
	 * Derived classes may override this method to declare external actions.
	 *
	 * Note, in order to inherit actions defined in the parent class, a child class needs to
	 * merge the parent actions with child actions using functions like array_merge().
	 *
	 * Since version 1.0.1, you may import actions from an action provider
	 * (such as a widget, see {@link CWidget::actions}), like the following:
	 * <pre>
	 * return array(
	 *     ...other actions...
	 *     // import actions declared in ProviderClass::actions()
	 *     // the action IDs will be prefixed with 'pro.'
	 *     'pro.'=>'path.to.ProviderClass',
	 *     // similar as above except that the imported actions are
	 *     // configured with the specified initial property values
	 *     'pro2.'=>array(
	 *         'class'=>'path.to.ProviderClass',
	 *         'action1'=>array(
	 *             'property1'=>'value1',
	 *         ),
	 *         'action2'=>array(
	 *             'property2'=>'value2',
	 *         ),
	 *     ),
	 * )
	 * </pre>
	 *
	 * In the above, we differentiate action providers from other action
	 * declarations by the array keys. For action providers, the array keys
	 * must contain a dot. As a result, an action ID 'pro2.action1' will
	 * be resolved as the 'action1' action declared in the 'ProviderClass'.
	 *
	 * @return array list of external action classes
	 * @see createAction
	 */
	public function actions()
	{
		return array();
	}

	/**
	 * Returns a list of behaviors that this controller should behave as.
	 * The return value should be an array of behavior configurations indexed by
	 * behavior names. Each behavior configuration can be either a string specifying
	 * the behavior class or an array of the following structure:
	 * <pre>
	 * 'behaviorName'=>array(
	 *     'class'=>'path.to.BehaviorClass',
	 *     'property1'=>'value1',
	 *     'property2'=>'value2',
	 * )
	 * </pre>
	 *
	 * Note, the behavior classes must implement {@link IBehavior} or extend from
	 * {@link CBehavior}. Behaviors declared in this method will be attached
	 * to the controller when it is instantiated.
	 *
	 * For more details about behaviors, see {@link CComponent}.
	 * @return array the behavior configurations (behavior name=>behavior configuration)
	 * @since 1.0.6
	 */
	public function behaviors()
	{
		return array();
	}

	/**
	 * Returns the access rules for this controller.
	 * Override this method if you use the {@link filterAccessControl accessControl} filter.
	 * @return array list of access rules. See {@link CAccessControlFilter} for details about rule specification.
	 */
	public function accessRules()
	{
		return array();
	}

	/**
	 * Runs the named action.
	 * Filters specified via {@link filters()} will be applied.
	 * @param string $actionID action ID
	 * @throws CHttpException if the action does not exist or the action name is not proper.
	 * @see filters
	 * @see createAction
	 * @see runAction
	 */
	public function run($actionID)
	{
		if(($action=$this->createAction($actionID))!==null)
		{
			if(($parent=$this->getModule())===null)
				$parent=Yii::app();
			if($parent->beforeControllerAction($this,$action))
			{
				$this->runActionWithFilters($action,$this->filters());
				$parent->afterControllerAction($this,$action);
			}
		}
		else
			$this->missingAction($actionID);
	}

	/**
	 * Runs an action with the specified filters.
	 * A filter chain will be created based on the specified filters
	 * and the action will be executed then.
	 * @param CAction $action the action to be executed.
	 * @param array $filters list of filters to be applied to the action.
	 * @see filters
	 * @see createAction
	 * @see runAction
	 */
	public function runActionWithFilters($action,$filters)
	{
		if(empty($filters))
			$this->runAction($action);
		else
		{
			$priorAction=$this->_action;
			$this->_action=$action;
			CFilterChain::create($this,$action,$filters)->run();
			$this->_action=$priorAction;
		}
	}

	/**
	 * Runs the action after passing through all filters.
	 * This method is invoked by {@link runActionWithFilters} after all possible filters have been executed
	 * and the action starts to run.
	 * @param CAction $action action to run
	 */
	public function runAction($action)
	{
		$priorAction=$this->_action;
		$this->_action=$action;
		if($this->beforeAction($action))
		{
			if($action->runWithParams($this->getActionParams())===false)
				$this->invalidActionParams($action);
			else
				$this->afterAction($action);
		}
		$this->_action=$priorAction;
	}

	/**
	 * Returns the request parameters that will be used for action parameter binding.
	 * By default, this method will return $_GET. You may override this method if you
	 * want to use other request parameters (e.g. $_GET+$_POST).
	 * @return array the request parameters to be used for action parameter binding
	 * @since 1.1.7
	 */
	public function getActionParams()
	{
		return $_GET;
	}

	/**
	 * This method is invoked when the request parameters do not satisfy the requirement of the specified action.
	 * The default implementation will throw a 400 HTTP exception.
	 * @param CAction $action the action being executed
	 * @since 1.1.7
	 */
	public function invalidActionParams($action)
	{
		throw new CHttpException(400,Yii::t('yii','Your request is invalid.'));
	}

	/**
	 * Postprocesses the output generated by {@link render()}.
	 * This method is invoked at the end of {@link render()} and {@link renderText()}.
	 * If there are registered client scripts, this method will insert them into the output
	 * at appropriate places. If there are dynamic contents, they will also be inserted.
	 * This method may also save the persistent page states in hidden fields of
	 * stateful forms in the page.
	 * @param string $output the output generated by the current action
	 * @return string the output that has been processed.
	 */
	public function processOutput($output)
	{
		Yii::app()->getClientScript()->render($output);

		// if using page caching, we should delay dynamic output replacement
		if($this->_dynamicOutput!==null && $this->isCachingStackEmpty())
		{
			$output=$this->processDynamicOutput($output);
			$this->_dynamicOutput=null;
		}

		if($this->_pageStates===null)
			$this->_pageStates=$this->loadPageStates();
		if(!empty($this->_pageStates))
			$this->savePageStates($this->_pageStates,$output);

		return $output;
	}

	/**
	 * Postprocesses the dynamic output.
	 * This method is internally used. Do not call this method directly.
	 * @param string $output output to be processed
	 * @return string the processed output
	 * @since 1.0.4
	 */
	public function processDynamicOutput($output)
	{
		if($this->_dynamicOutput)
		{
			$output=preg_replace_callback('/<###dynamic-(\d+)###>/',array($this,'replaceDynamicOutput'),$output);
		}
		return $output;
	}

	/**
	 * Replaces the dynamic content placeholders with actual content.
	 * This is a callback function used internally.
	 * @param array $matches matches
	 * @return string the replacement
	 * @see processOutput
	 */
	protected function replaceDynamicOutput($matches)
	{
		$content=$matches[0];
		if(isset($this->_dynamicOutput[$matches[1]]))
		{
			$content=$this->_dynamicOutput[$matches[1]];
			$this->_dynamicOutput[$matches[1]]=null;
		}
		return $content;
	}

	/**
	 * Creates the action instance based on the action name.
	 * The action can be either an inline action or an object.
	 * The latter is created by looking up the action map specified in {@link actions}.
	 * @param string $actionID ID of the action. If empty, the {@link defaultAction default action} will be used.
	 * @return CAction the action instance, null if the action does not exist.
	 * @see actions
	 */
	public function createAction($actionID)
	{
		if($actionID==='')
			$actionID=$this->defaultAction;
		if(method_exists($this,'action'.$actionID) && strcasecmp($actionID,'s')) // we have actions method
			return new CInlineAction($this,$actionID);
		else
		{
			$action=$this->createActionFromMap($this->actions(),$actionID,$actionID);
			if($action!==null && !method_exists($action,'run'))
				throw new CException(Yii::t('yii', 'Action class {class} must implement the "run" method.', array('{class}'=>get_class($action))));
			return $action;
		}
	}

	/**
	 * Creates the action instance based on the action map.
	 * This method will check to see if the action ID appears in the given
	 * action map. If so, the corresponding configuration will be used to
	 * create the action instance.
	 * @param array $actionMap the action map
	 * @param string $actionID the action ID that has its prefix stripped off
	 * @param string $requestActionID the originally requested action ID
	 * @param array $config the action configuration that should be applied on top of the configuration specified in the map
	 * @return CAction the action instance, null if the action does not exist.
	 * @since 1.0.1
	 */
	protected function createActionFromMap($actionMap,$actionID,$requestActionID,$config=array())
	{
		if(($pos=strpos($actionID,'.'))===false && isset($actionMap[$actionID]))
		{
			$baseConfig=is_array($actionMap[$actionID]) ? $actionMap[$actionID] : array('class'=>$actionMap[$actionID]);
			return Yii::createComponent(empty($config)?$baseConfig:array_merge($baseConfig,$config),$this,$requestActionID);
		}
		else if($pos===false)
			return null;

		// the action is defined in a provider
		$prefix=substr($actionID,0,$pos+1);
		if(!isset($actionMap[$prefix]))
			return null;
		$actionID=(string)substr($actionID,$pos+1);

		$provider=$actionMap[$prefix];
		if(is_string($provider))
			$providerType=$provider;
		else if(is_array($provider) && isset($provider['class']))
		{
			$providerType=$provider['class'];
			if(isset($provider[$actionID]))
			{
				if(is_string($provider[$actionID]))
					$config=array_merge(array('class'=>$provider[$actionID]),$config);
				else
					$config=array_merge($provider[$actionID],$config);
			}
		}
		else
			throw new CException(Yii::t('yii','Object configuration must be an array containing a "class" element.'));

		$class=Yii::import($providerType,true);
		$map=call_user_func(array($class,'actions'));

		return $this->createActionFromMap($map,$actionID,$requestActionID,$config);
	}

	/**
	 * Handles the request whose action is not recognized.
	 * This method is invoked when the controller cannot find the requested action.
	 * The default implementation simply throws an exception.
	 * @param string $actionID the missing action name
	 * @throws CHttpException whenever this method is invoked
	 */
	public function missingAction($actionID)
	{
		throw new CHttpException(404,Yii::t('yii','The system is unable to find the requested action "{action}".',
			array('{action}'=>$actionID==''?$this->defaultAction:$actionID)));
	}

	/**
	 * @return CAction the action currently being executed, null if no active action.
	 */
	public function getAction()
	{
		return $this->_action;
	}

	/**
	 * @param CAction $value the action currently being executed.
	 */
	public function setAction($value)
	{
		$this->_action=$value;
	}

	/**
	 * @return string ID of the controller
	 */
	public function getId()
	{
		return $this->_id;
	}

	/**
	 * @return string the controller ID that is prefixed with the module ID (if any).
	 * @since 1.0.3
	 */
	public function getUniqueId()
	{
		return $this->_module ? $this->_module->getId().'/'.$this->_id : $this->_id;
	}

	/**
	 * @return string the route (module ID, controller ID and action ID) of the current request.
	 * @since 1.1.0
	 */
	public function getRoute()
	{
		if(($action=$this->getAction())!==null)
			return $this->getUniqueId().'/'.$action->getId();
		else
			return $this->getUniqueId();
	}

	/**
	 * @return CWebModule the module that this controller belongs to. It returns null
	 * if the controller does not belong to any module
	 * @since 1.0.3
	 */
	public function getModule()
	{
		return $this->_module;
	}

	/**
	 * Returns the directory containing view files for this controller.
	 * The default implementation returns 'protected/views/ControllerID'.
	 * Child classes may override this method to use customized view path.
	 * If the controller belongs to a module (since version 1.0.3), the default view path
	 * is the {@link CWebModule::getViewPath module view path} appended with the controller ID.
	 * @return string the directory containing the view files for this controller. Defaults to 'protected/views/ControllerID'.
	 */
	public function getViewPath()
	{
		if(($module=$this->getModule())===null)
			$module=Yii::app();
		return $module->getViewPath().DIRECTORY_SEPARATOR.$this->getId();
	}

	/**
	 * Looks for the view file according to the given view name.
	 *
	 * When a theme is currently active, this method will call {@link CTheme::getViewFile} to determine
	 * which view file should be returned.
	 *
	 * Otherwise, this method will return the corresponding view file based on the following criteria:
	 * <ul>
	 * <li>absolute view within a module: the view name starts with a single slash '/'.
	 * In this case, the view will be searched for under the currently active module's view path.
	 * If there is no active module, the view will be searched for under the application's view path.</li>
	 * <li>absolute view within the application: the view name starts with double slashes '//'.
	 * In this case, the view will be searched for under the application's view path.
	 * This syntax has been available since version 1.1.3.</li>
	 * <li>aliased view: the view name contains dots and refers to a path alias.
	 * The view file is determined by calling {@link YiiBase::getPathOfAlias()}. Note that aliased views
	 * cannot be themed because they can refer to a view file located at arbitrary places.</li>
	 * <li>relative view: otherwise. Relative views will be searched for under the currently active
	 * controller's view path.</li>
	 * </ul>
	 *
	 * After the view file is identified, this method may further call {@link CApplication::findLocalizedFile}
	 * to find its localized version if internationalization is needed.
	 *
	 * @param string $viewName view name
	 * @return string the view file path, false if the view file does not exist
	 * @see resolveViewFile
	 * @see CApplication::findLocalizedFile
	 */
	public function getViewFile($viewName)
	{
		if(($theme=Yii::app()->getTheme())!==null && ($viewFile=$theme->getViewFile($this,$viewName))!==false)
			return $viewFile;
		$moduleViewPath=$basePath=Yii::app()->getViewPath();
		if(($module=$this->getModule())!==null)
			$moduleViewPath=$module->getViewPath();
		return $this->resolveViewFile($viewName,$this->getViewPath(),$basePath,$moduleViewPath);
	}

	/**
	 * Looks for the layout view script based on the layout name.
	 *
	 * The layout name can be specified in one of the following ways:
	 *
	 * <ul>
	 * <li>layout is false: returns false, meaning no layout.</li>
	 * <li>layout is null: the currently active module's layout will be used. If there is no active module,
	 * the application's layout will be used.</li>
	 * <li>a regular view name.</li>
	 * </ul>
	 *
	 * The resolution of the view file based on the layout view is similar to that in {@link getViewFile}.
	 * In particular, the following rules are followed:
	 *
	 * Otherwise, this method will return the corresponding view file based on the following criteria:
	 * <ul>
	 * <li>When a theme is currently active, this method will call {@link CTheme::getLayoutFile} to determine
	 * which view file should be returned.</li>
	 * <li>absolute view within a module: the view name starts with a single slash '/'.
	 * In this case, the view will be searched for under the currently active module's view path.
	 * If there is no active module, the view will be searched for under the application's view path.</li>
	 * <li>absolute view within the application: the view name starts with double slashes '//'.
	 * In this case, the view will be searched for under the application's view path.
	 * This syntax has been available since version 1.1.3.</li>
	 * <li>aliased view: the view name contains dots and refers to a path alias.
	 * The view file is determined by calling {@link YiiBase::getPathOfAlias()}. Note that aliased views
	 * cannot be themed because they can refer to a view file located at arbitrary places.</li>
	 * <li>relative view: otherwise. Relative views will be searched for under the currently active
	 * module's layout path. In case when there is no active module, the view will be searched for
	 * under the application's layout path.</li>
	 * </ul>
	 *
	 * After the view file is identified, this method may further call {@link CApplication::findLocalizedFile}
	 * to find its localized version if internationalization is needed.
	 *
	 * @param mixed $layoutName layout name
	 * @return string the view file for the layout. False if the view file cannot be found
	 */
	public function getLayoutFile($layoutName)
	{
		if($layoutName===false)
			return false;
		if(($theme=Yii::app()->getTheme())!==null && ($layoutFile=$theme->getLayoutFile($this,$layoutName))!==false)
			return $layoutFile;

		if(empty($layoutName))
		{
			$module=$this->getModule();
			while($module!==null)
			{
				if($module->layout===false)
					return false;
				if(!empty($module->layout))
					break;
				$module=$module->getParentModule();
			}
			if($module===null)
				$module=Yii::app();
			$layoutName=$module->layout;
		}
		else if(($module=$this->getModule())===null)
			$module=Yii::app();

		return $this->resolveViewFile($layoutName,$module->getLayoutPath(),Yii::app()->getViewPath(),$module->getViewPath());
	}

	/**
	 * Finds a view file based on its name.
	 * The view name can be in one of the following formats:
	 * <ul>
	 * <li>absolute view within a module: the view name starts with a single slash '/'.
	 * In this case, the view will be searched for under the currently active module's view path.
	 * If there is no active module, the view will be searched for under the application's view path.</li>
	 * <li>absolute view within the application: the view name starts with double slashes '//'.
	 * In this case, the view will be searched for under the application's view path.
	 * This syntax has been available since version 1.1.3.</li>
	 * <li>aliased view: the view name contains dots and refers to a path alias.
	 * The view file is determined by calling {@link YiiBase::getPathOfAlias()}. Note that aliased views
	 * cannot be themed because they can refer to a view file located at arbitrary places.</li>
	 * <li>relative view: otherwise. Relative views will be searched for under the currently active
	 * controller's view path.</li>
	 * </ul>
	 * For absolute view and relative view, the corresponding view file is a PHP file
	 * whose name is the same as the view name. The file is located under a specified directory.
	 * This method will call {@link CApplication::findLocalizedFile} to search for a localized file, if any.
	 * @param string $viewName the view name
	 * @param string $viewPath the directory that is used to search for a relative view name
	 * @param string $basePath the directory that is used to search for an absolute view name under the application
	 * @param string $moduleViewPath the directory that is used to search for an absolute view name under the current module.
	 * If this is not set, the application base view path will be used.
	 * @return mixed the view file path. False if the view file does not exist.
	 * @since 1.0.3
	 */
	public function resolveViewFile($viewName,$viewPath,$basePath,$moduleViewPath=null)
	{
		if(empty($viewName))
			return false;

		if($moduleViewPath===null)
			$moduleViewPath=$basePath;

		if(($renderer=Yii::app()->getViewRenderer())!==null)
			$extension=$renderer->fileExtension;
		else
			$extension='.php';
		if($viewName[0]==='/')
		{
			if(strncmp($viewName,'//',2)===0)
				$viewFile=$basePath.$viewName;
			else
				$viewFile=$moduleViewPath.$viewName;
		}
		else if(strpos($viewName,'.'))
			$viewFile=Yii::getPathOfAlias($viewName);
		else
			$viewFile=$viewPath.DIRECTORY_SEPARATOR.$viewName;

		if(is_file($viewFile.$extension))
			return Yii::app()->findLocalizedFile($viewFile.$extension);
		else if($extension!=='.php' && is_file($viewFile.'.php'))
			return Yii::app()->findLocalizedFile($viewFile.'.php');
		else
			return false;
	}

	/**
	 * Returns the list of clips.
	 * A clip is a named piece of rendering result that can be
	 * inserted at different places.
	 * @return CMap the list of clips
	 * @see CClipWidget
	 */
	public function getClips()
	{
		if($this->_clips!==null)
			return $this->_clips;
		else
			return $this->_clips=new CMap;
	}

	/**
	 * Processes the request using another controller action.
	 * This is like {@link redirect}, but the user browser's URL remains unchanged.
	 * In most cases, you should call {@link redirect} instead of this method.
	 * @param string $route the route of the new controller action. This can be an action ID, or a complete route
	 * with module ID (optional in the current module), controller ID and action ID. If the former, the action is assumed
	 * to be located within the current controller.
	 * @param boolean $exit whether to end the application after this call. Defaults to true.
	 * @since 1.1.0
	 */
	public function forward($route,$exit=true)
	{
		if(strpos($route,'/')===false)
			$this->run($route);
		else
		{
			if($route[0]!=='/' && ($module=$this->getModule())!==null)
				$route=$module->getId().'/'.$route;
			Yii::app()->runController($route);
		}
		if($exit)
			Yii::app()->end();
	}

	/**
	 * Renders a view with a layout.
	 *
	 * This method first calls {@link renderPartial} to render the view (called content view).
	 * It then renders the layout view which may embed the content view at appropriate place.
	 * In the layout view, the content view rendering result can be accessed via variable
	 * <code>$content</code>. At the end, it calls {@link processOutput} to insert scripts
	 * and dynamic contents if they are available.
	 *
	 * By default, the layout view script is "protected/views/layouts/main.php".
	 * This may be customized by changing {@link layout}.
	 *
	 * @param string $view name of the view to be rendered. See {@link getViewFile} for details
	 * about how the view script is resolved.
	 * @param array $data data to be extracted into PHP variables and made available to the view script
	 * @param boolean $return whether the rendering result should be returned instead of being displayed to end users.
	 * @return string the rendering result. Null if the rendering result is not required.
	 * @see renderPartial
	 * @see getLayoutFile
	 */
	public function render($view,$data=null,$return=false)
	{
		if($this->beforeRender($view))
		{
			$output=$this->renderPartial($view,$data,true);
			if(($layoutFile=$this->getLayoutFile($this->layout))!==false)
				$output=$this->renderFile($layoutFile,array('content'=>$output),true);

			$this->afterRender($view,$output);

			$output=$this->processOutput($output);

			if($return)
				return $output;
			else
				echo $output;
		}
	}

	/**
	 * This method is invoked at the beginning of {@link render()}.
	 * You may override this method to do some preprocessing when rendering a view.
	 * @param string $view the view to be rendered
	 * @return boolean whether the view should be rendered.
	 * @since 1.1.5
	 */
	protected function beforeRender($view)
	{
		return true;
	}

	/**
	 * This method is invoked after the specified is rendered by calling {@link render()}.
	 * Note that this method is invoked BEFORE {@link processOutput()}.
	 * You may override this method to do some postprocessing for the view rendering.
	 * @param string $view the view that has been rendered
	 * @param string $output the rendering result of the view. Note that this parameter is passed
	 * as a reference. That means you can modify it within this method.
	 * @since 1.1.5
	 */
	protected function afterRender($view, &$output)
	{
	}

	/**
	 * Renders a static text string.
	 * The string will be inserted in the current controller layout and returned back.
	 * @param string $text the static text string
	 * @param boolean $return whether the rendering result should be returned instead of being displayed to end users.
	 * @return string the rendering result. Null if the rendering result is not required.
	 * @see getLayoutFile
	 */
	public function renderText($text,$return=false)
	{
		if(($layoutFile=$this->getLayoutFile($this->layout))!==false)
			$text=$this->renderFile($layoutFile,array('content'=>$text),true);

		$text=$this->processOutput($text);

		if($return)
			return $text;
		else
			echo $text;
	}

	/**
	 * Renders a view.
	 *
	 * The named view refers to a PHP script (resolved via {@link getViewFile})
	 * that is included by this method. If $data is an associative array,
	 * it will be extracted as PHP variables and made available to the script.
	 *
	 * This method differs from {@link render()} in that it does not
	 * apply a layout to the rendered result. It is thus mostly used
	 * in rendering a partial view, or an AJAX response.
	 *
	 * @param string $view name of the view to be rendered. See {@link getViewFile} for details
	 * about how the view script is resolved.
	 * @param array $data data to be extracted into PHP variables and made available to the view script
	 * @param boolean $return whether the rendering result should be returned instead of being displayed to end users
	 * @param boolean $processOutput whether the rendering result should be postprocessed using {@link processOutput}.
	 * @return string the rendering result. Null if the rendering result is not required.
	 * @throws CException if the view does not exist
	 * @see getViewFile
	 * @see processOutput
	 * @see render
	 */
	public function renderPartial($view,$data=null,$return=false,$processOutput=false)
	{
		if(($viewFile=$this->getViewFile($view))!==false)
		{
			$output=$this->renderFile($viewFile,$data,true);
			if($processOutput)
				$output=$this->processOutput($output);
			if($return)
				return $output;
			else
				echo $output;
		}
		else
			throw new CException(Yii::t('yii','{controller} cannot find the requested view "{view}".',
				array('{controller}'=>get_class($this), '{view}'=>$view)));
	}

	/**
	 * Renders a named clip with the supplied parameters.
	 * This is similar to directly accessing the {@link clips} property.
	 * The main difference is that it can take an array of named parameters
	 * which will replace the corresponding placeholders in the clip.
	 * @param string $name the name of the clip
	 * @param array $params an array of named parameters (name=>value) that should replace
	 * their corresponding placeholders in the clip
	 * @param boolean $return whether to return the clip content or echo it.
	 * @return mixed either the clip content or null
	 * @since 1.1.8
	 */
	public function renderClip($name,$params=array(),$return=false)
	{
		$text=isset($this->clips[$name]) ? strtr($this->clips[$name], $params) : '';

		if($return)
			return $text;
		else
			echo $text;
	}

	/**
	 * Renders dynamic content returned by the specified callback.
	 * This method is used together with {@link COutputCache}. Dynamic contents
	 * will always show as their latest state even if the content surrounding them is being cached.
	 * This is especially useful when caching pages that are mostly static but contain some small
	 * dynamic regions, such as username or current time.
	 * We can use this method to render these dynamic regions to ensure they are always up-to-date.
	 *
	 * The first parameter to this method should be a valid PHP callback, while the rest parameters
	 * will be passed to the callback.
	 *
	 * Note, the callback and its parameter values will be serialized and saved in cache.
	 * Make sure they are serializable.
	 *
	 * @param callback $callback a PHP callback which returns the needed dynamic content.
	 * When the callback is specified as a string, it will be first assumed to be a method of the current
	 * controller class. If the method does not exist, it is assumed to be a global PHP function.
	 * Note, the callback should return the dynamic content instead of echoing it.
	 */
	public function renderDynamic($callback)
	{
		$n=count($this->_dynamicOutput);
		echo "<###dynamic-$n###>";
		$params=func_get_args();
		array_shift($params);
		$this->renderDynamicInternal($callback,$params);
	}

	/**
	 * This method is internally used.
	 * @param callback $callback a PHP callback which returns the needed dynamic content.
	 * @param array $params parameters passed to the PHP callback
	 * @see renderDynamic
	 */
	public function renderDynamicInternal($callback,$params)
	{
		$this->recordCachingAction('','renderDynamicInternal',array($callback,$params));
		if(is_string($callback) && method_exists($this,$callback))
			$callback=array($this,$callback);
		$this->_dynamicOutput[]=call_user_func_array($callback,$params);
	}

	/**
	 * Creates a relative URL for the specified action defined in this controller.
	 * @param string $route the URL route. This should be in the format of 'ControllerID/ActionID'.
	 * If the ControllerID is not present, the current controller ID will be prefixed to the route.
	 * If the route is empty, it is assumed to be the current action.
	 * Since version 1.0.3, if the controller belongs to a module, the {@link CWebModule::getId module ID}
	 * will be prefixed to the route. (If you do not want the module ID prefix, the route should start with a slash '/'.)
	 * @param array $params additional GET parameters (name=>value). Both the name and value will be URL-encoded.
	 * If the name is '#', the corresponding value will be treated as an anchor
	 * and will be appended at the end of the URL. This anchor feature has been available since version 1.0.1.
	 * @param string $ampersand the token separating name-value pairs in the URL.
	 * @return string the constructed URL
	 */
	public function createUrl($route,$params=array(),$ampersand='&')
	{
		if($route==='')
			$route=$this->getId().'/'.$this->getAction()->getId();
		else if(strpos($route,'/')===false)
			$route=$this->getId().'/'.$route;
		if($route[0]!=='/' && ($module=$this->getModule())!==null)
			$route=$module->getId().'/'.$route;
		return Yii::app()->createUrl(trim($route,'/'),$params,$ampersand);
	}

	/**
	 * Creates an absolute URL for the specified action defined in this controller.
	 * @param string $route the URL route. This should be in the format of 'ControllerID/ActionID'.
	 * If the ControllerPath is not present, the current controller ID will be prefixed to the route.
	 * If the route is empty, it is assumed to be the current action.
	 * @param array $params additional GET parameters (name=>value). Both the name and value will be URL-encoded.
	 * @param string $schema schema to use (e.g. http, https). If empty, the schema used for the current request will be used.
	 * @param string $ampersand the token separating name-value pairs in the URL.
	 * @return string the constructed URL
	 */
	public function createAbsoluteUrl($route,$params=array(),$schema='',$ampersand='&')
	{
		$url=$this->createUrl($route,$params,$ampersand);
		if(strpos($url,'http')===0)
			return $url;
		else
			return Yii::app()->getRequest()->getHostInfo($schema).$url;
	}

	/**
	 * @return string the page title. Defaults to the controller name and the action name.
	 */
	public function getPageTitle()
	{
		if($this->_pageTitle!==null)
			return $this->_pageTitle;
		else
		{
			$name=ucfirst(basename($this->getId()));
			if($this->getAction()!==null && strcasecmp($this->getAction()->getId(),$this->defaultAction))
				return $this->_pageTitle=Yii::app()->name.' - '.ucfirst($this->getAction()->getId()).' '.$name;
			else
				return $this->_pageTitle=Yii::app()->name.' - '.$name;
		}
	}

	/**
	 * @param string $value the page title.
	 */
	public function setPageTitle($value)
	{
		$this->_pageTitle=$value;
	}

	/**
	 * Redirects the browser to the specified URL or route (controller/action).
	 * @param mixed $url the URL to be redirected to. If the parameter is an array,
	 * the first element must be a route to a controller action and the rest
	 * are GET parameters in name-value pairs.
	 * @param boolean $terminate whether to terminate the current application after calling this method
	 * @param integer $statusCode the HTTP status code. Defaults to 302. See {@link http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html}
	 * for details about HTTP status code. This parameter has been available since version 1.0.4.
	 */
	public function redirect($url,$terminate=true,$statusCode=302)
	{
		if(is_array($url))
		{
			$route=isset($url[0]) ? $url[0] : '';
			$url=$this->createUrl($route,array_splice($url,1));
		}
		Yii::app()->getRequest()->redirect($url,$terminate,$statusCode);
	}

	/**
	 * Refreshes the current page.
	 * The effect of this method call is the same as user pressing the
	 * refresh button on the browser (without post data).
	 * @param boolean $terminate whether to terminate the current application after calling this method
	 * @param string $anchor the anchor that should be appended to the redirection URL.
	 * Defaults to empty. Make sure the anchor starts with '#' if you want to specify it.
	 * The parameter has been available since version 1.0.7.
	 **/
	public function refresh($terminate=true,$anchor='')
	{
		$this->redirect(Yii::app()->getRequest()->getUrl().$anchor,$terminate);
	}

	/**
	 * Records a method call when an output cache is in effect.
	 * When the content is served from the output cache, the recorded
	 * method will be re-invoked.
	 * @param string $context a property name of the controller. It refers to an object
	 * whose method is being called. If empty it means the controller itself.
	 * @param string $method the method name
	 * @param array $params parameters passed to the method
	 * @see COutputCache
	 */
	public function recordCachingAction($context,$method,$params)
	{
		if($this->_cachingStack) // record only when there is an active output cache
		{
			foreach($this->_cachingStack as $cache)
				$cache->recordAction($context,$method,$params);
		}
	}

	/**
	 * @param boolean $createIfNull whether to create a stack if it does not exist yet. Defaults to true.
	 * @return CStack stack of {@link COutputCache} objects
	 */
	public function getCachingStack($createIfNull=true)
	{
		if(!$this->_cachingStack)
			$this->_cachingStack=new CStack;
		return $this->_cachingStack;
	}

	/**
	 * Returns whether the caching stack is empty.
	 * @return boolean whether the caching stack is empty. If not empty, it means currently there are
	 * some output cache in effect. Note, the return result of this method may change when it is
	 * called in different output regions, depending on the partition of output caches.
	 * @since 1.0.5
	 */
	public function isCachingStackEmpty()
	{
		return $this->_cachingStack===null || !$this->_cachingStack->getCount();
	}

	/**
	 * This method is invoked right before an action is to be executed (after all possible filters.)
	 * You may override this method to do last-minute preparation for the action.
	 * @param CAction $action the action to be executed.
	 * @return boolean whether the action should be executed.
	 */
	protected function beforeAction($action)
	{
		return true;
	}

	/**
	 * This method is invoked right after an action is executed.
	 * You may override this method to do some postprocessing for the action.
	 * @param CAction $action the action just executed.
	 */
	protected function afterAction($action)
	{
	}

	/**
	 * The filter method for 'postOnly' filter.
	 * This filter reports an error if the applied action is receiving a non-POST request.
	 * @param CFilterChain $filterChain the filter chain that the filter is on.
	 * @throws CHttpException if the current request is not a POST request
	 */
	public function filterPostOnly($filterChain)
	{
		if(Yii::app()->getRequest()->getIsPostRequest())
			$filterChain->run();
		else
			throw new CHttpException(400,Yii::t('yii','Your request is invalid.'));
	}

	/**
	 * The filter method for 'ajaxOnly' filter.
	 * This filter reports an error if the applied action is receiving a non-AJAX request.
	 * @param CFilterChain $filterChain the filter chain that the filter is on.
	 * @throws CHttpException if the current request is not an AJAX request.
	 */
	public function filterAjaxOnly($filterChain)
	{
		if(Yii::app()->getRequest()->getIsAjaxRequest())
			$filterChain->run();
		else
			throw new CHttpException(400,Yii::t('yii','Your request is invalid.'));
	}

	/**
	 * The filter method for 'accessControl' filter.
	 * This filter is a wrapper of {@link CAccessControlFilter}.
	 * To use this filter, you must override {@link accessRules} method.
	 * @param CFilterChain $filterChain the filter chain that the filter is on.
	 */
	public function filterAccessControl($filterChain)
	{
		$filter=new CAccessControlFilter;
		$filter->setRules($this->accessRules());
		$filter->filter($filterChain);
	}

	/**
	 * Returns a persistent page state value.
	 * A page state is a variable that is persistent across POST requests of the same page.
	 * In order to use persistent page states, the form(s) must be stateful
	 * which are generated using {@link CHtml::statefulForm}.
	 * @param string $name the state name
	 * @param mixed $defaultValue the value to be returned if the named state is not found
	 * @return mixed the page state value
	 * @see setPageState
	 * @see CHtml::statefulForm
	 */
	public function getPageState($name,$defaultValue=null)
	{
		if($this->_pageStates===null)
			$this->_pageStates=$this->loadPageStates();
		return isset($this->_pageStates[$name])?$this->_pageStates[$name]:$defaultValue;
	}

	/**
	 * Saves a persistent page state value.
	 * A page state is a variable that is persistent across POST requests of the same page.
	 * In order to use persistent page states, the form(s) must be stateful
	 * which are generated using {@link CHtml::statefulForm}.
	 * @param string $name the state name
	 * @param mixed $value the page state value
	 * @param mixed $defaultValue the default page state value. If this is the same as
	 * the given value, the state will be removed from persistent storage.
	 * @see getPageState
	 * @see CHtml::statefulForm
	 */
	public function setPageState($name,$value,$defaultValue=null)
	{
		if($this->_pageStates===null)
			$this->_pageStates=$this->loadPageStates();
		if($value===$defaultValue)
			unset($this->_pageStates[$name]);
		else
			$this->_pageStates[$name]=$value;

		$params=func_get_args();
		$this->recordCachingAction('','setPageState',$params);
	}

	/**
	 * Removes all page states.
	 */
	public function clearPageStates()
	{
		$this->_pageStates=array();
	}

	/**
	 * Loads page states from a hidden input.
	 * @return array the loaded page states
	 */
	protected function loadPageStates()
	{
		if(!empty($_POST[self::STATE_INPUT_NAME]))
		{
			if(($data=base64_decode($_POST[self::STATE_INPUT_NAME]))!==false)
			{
				if(extension_loaded('zlib'))
					$data=@gzuncompress($data);
				if(($data=Yii::app()->getSecurityManager()->validateData($data))!==false)
					return unserialize($data);
			}
		}
		return array();
	}

	/**
	 * Saves page states as a base64 string.
	 * @param array $states the states to be saved.
	 * @param string $output the output to be modified. Note, this is passed by reference.
	 */
	protected function savePageStates($states,&$output)
	{
		$data=Yii::app()->getSecurityManager()->hashData(serialize($states));
		if(extension_loaded('zlib'))
			$data=gzcompress($data);
		$value=base64_encode($data);
		$output=str_replace(CHtml::pageStateField(''),CHtml::pageStateField($value),$output);
	}
}