AuthFilter class from the Auth module for the Yii PHP framework.

AuthFilter.php

<?php
/**
 * AuthFilter class file.
 * @author Christoffer Niska <ChristofferNiska@gmail.com>
 * @copyright Copyright &copy; Christoffer Niska 2012-
 * @license http://www.opensource.org/licenses/bsd-license.php New BSD License
 * @package auth.components
 */

/**
 * Filter that automatically checks if the user has access to the current controller action.
 */
class AuthFilter extends CFilter
{
  /**
	 * @var array name-value pairs that would be passed to business rules associated
	 * with the tasks and roles assigned to the user.
	 */
	public $params = array();

	/**
	 * Performs the pre-action filtering.
	 * @param CFilterChain $filterChain the filter chain that the filter is on.
	 * @return boolean whether the filtering process should continue and the action should be executed.
	 * @throws CHttpException if the user is denied access.
	 */
	protected function preFilter($filterChain)
	{
		$itemName = '';
		$controller = $filterChain->controller;

		if (($module = $controller->getModule()) !== null)
			$itemName .= $module->getId() . '.';

		$itemName .= $controller->getId();

		/* @var $user CWebUser */
		$user = Yii::app()->getUser();

		if ($user->checkAccess($itemName . '.*'))
			return true;

		$itemName .= '.' . $controller->action->getId();
		if ($user->checkAccess($itemName, $this->params))
			return true;

		throw new CHttpException(401, Yii::t('AuthModule.main', 'Access denied.'));
	}
}