YII Framework的filter过滤器用法分析

public function filterAccessControl($filterChain)
{
  // 调用 $filterChain->run() 以继续后续过滤器与动作的执行。
}

class PerformanceFilter extends CFilter
{
  protected function preFilter($filterChain)
  {
    // 动作被执行之前应用的逻辑
    return true; // 如果动作不应被执行，此处返回 false
  }
  protected function postFilter($filterChain)
  {
    // 动作执行之后应用的逻辑
  }
}

class PostController extends CController
{
  ......
  public function filters()
  {
    return array(
      'postOnly   edit, create',
      array(
        'application.filters.PerformanceFilter - edit, create',
        'unit'=>'second',
      ),
    );
  }
}

public function filterAccessControl($filterChain)
{ 
echo "--->filterAccessControl";
  $filterChain->run();
}

<?php 
/** 
 * CFilter is the base class for all filters. 
 * 
 * A filter can be applied before and after an action is executed. 
 * It can modify the context that the action is to run or decorate the result that the 
 * action generates. 
 * 
 * Override {@link preFilter()} to specify the filtering logic that should be applied 
 * before the action, and {@link postFilter()} for filtering logic after the action. 
 * 
 * @author Qiang Xue <qiang.xue@gmail.com> 
 * @version $Id: CFilter.php 2799 2011-01-01 19:31:13Z qiang.xue $ 
 * @package system.web.filters 
 * @since 1.0 
 */ 
class CFilter extends CComponent implements IFilter 
{ 
  /** 
   * Performs the filtering. 
   * The default implementation is to invoke {@link preFilter} 
   * and {@link postFilter} which are meant to be overridden 
   * child classes. If a child class needs to override this method, 
   * make sure it calls <code>$filterChain->run()</code> 
   * if the action should be executed. 
   * @param CFilterChain $filterChain the filter chain that the filter is on. 
   */ 
  public function filter($filterChain) 
  { 
    if($this->preFilter($filterChain)) 
    { 
      $filterChain->run(); 
      $this->postFilter($filterChain); 
    } 
  } 
  /** 
   * Initializes the filter. 
   * This method is invoked after the filter properties are initialized 
   * and before {@link preFilter} is called. 
   * You may override this method to include some initialization logic. 
   * @since 1.1.4 
   */ 
  public function init() 
  { 
  } 
  /** 
   * Performs the pre-action filtering. 
   * @param CFilterChain $filterChain the filter chain that the filter is on. 
   * @return boolean whether the filtering process should continue and the action 
   * should be executed. 
   */ 
  protected function preFilter($filterChain) 
  { 
    return true; 
  } 
  /** 
   * Performs the post-action filtering. 
   * @param CFilterChain $filterChain the filter chain that the filter is on. 
   */ 
  protected function postFilter($filterChain) 
  { 
  } 
}

<?php 
class SiteController extends Controller 
{ 
  public function init() 
  { 
    //$this->layout='mylayout'; 
  } 
  public function filters() 
    { 
      return array( 
        'AccessControl - create', 
        array( 
          'application.filters.MyFilter   create', 
        ), 
      ); 
  } 
  public function filterAccessControl($filterChain) 
  {     
      echo "--->filterAccessControl"; 
      $filterChain->run(); 
  } 
  public function actionCreate() { 
    echo "--->create action"; 
  } 
  public function actionPrint() { 
    echo "--->print action"; 
  } 

<?php 
class MyFilter extends CFilter 
{ 
  protected function preFilter ($filterChain) 
  { 
    // logic being applied before the action is executed     
    echo "-->MyFilter-->pre"; 
    return true; // false if the action should not be executed 
  } 
  protected function postFilter ($filterChain) 
  { 
    echo "-->MyFilter-->post"; 
  } 
} 

public function filters()
{
  return array(
    'AccessControl - create',
    array(
      'application.filters.MyFilter   create,print',
    ),
  );
}