<?php
  /**
   * ownCloud - App Framework
   *
   * @author Bernhard Posselt

   * @copyright 2012 Bernhard Posselt <dev@bernhard-posselt.com>

   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
   * License as published by the Free Software Foundation; either
   * version 3 of the License, or any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU AFFERO GENERAL PUBLIC LICENSE for more details.
   *
   * You should have received a copy of the GNU Affero General Public
   * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
   *
   */
  
  /**
   * Public interface of ownCloud for apps to use.
   * AppFramework\Middleware class
   */
  
  namespace OCP\AppFramework;
  
  use OCP\AppFramework\Controller;
  use OCP\AppFramework\Http\Response;
  
  
  /**
   * Middleware is used to provide hooks before or after controller methods and
   * deal with possible exceptions raised in the controller methods.
   * They're modeled after Django's middleware system:
   * https://docs.djangoproject.com/en/dev/topics/http/middleware/
   */
  abstract class Middleware {
  
  
  	/**
  	 * This is being run in normal order before the controller is being
  	 * called which allows several modifications and checks
  	 *
  	 * @param Controller $controller the controller that is being called
  	 * @param string $methodName the name of the method that will be called on
  	 *                           the controller
  	 */
  	public function beforeController($controller, $methodName){
  
  	}
  
  
  	/**
  	 * This is being run when either the beforeController method or the
  	 * controller method itself is throwing an exception. The middleware is
  	 * asked in reverse order to handle the exception and to return a response.
  	 * If the response is null, it is assumed that the exception could not be
  	 * handled and the error will be thrown again
  	 *
  	 * @param Controller $controller the controller that is being called
  	 * @param string $methodName the name of the method that will be called on
  	 *                           the controller
  	 * @param \Exception $exception the thrown exception
  	 * @throws \Exception the passed in exception if it cant handle it
  	 * @return Response a Response object in case that the exception was handled
  	 */
  	public function afterException($controller, $methodName, \Exception $exception){
  		throw $exception;
  	}
  
  
  	/**
  	 * This is being run after a successful controllermethod call and allows
  	 * the manipulation of a Response object. The middleware is run in reverse order
  	 *
  	 * @param Controller $controller the controller that is being called
  	 * @param string $methodName the name of the method that will be called on
  	 *                           the controller
  	 * @param Response $response the generated response from the controller
  	 * @return Response a Response object
  	 */
  	public function afterController($controller, $methodName, Response $response){
  		return $response;
  	}
  
  
  	/**
  	 * This is being run after the response object has been rendered and
  	 * allows the manipulation of the output. The middleware is run in reverse order
  	 *
  	 * @param Controller $controller the controller that is being called
  	 * @param string $methodName the name of the method that will be called on
  	 *                           the controller
  	 * @param string $output the generated output from a response
  	 * @return string the output that should be printed
  	 */
  	public function beforeOutput($controller, $methodName, $output){
  		return $output;
  	}
  
  }