友好错误提示页原文

Kohana3并没有像ko2默认有方法显示友好的错误页;这个快速教程将教你怎么做.原文 seen in Kohana 2; In this short guide you will learn how it is done.

Prerequisites

需要在’Kohana::init’中开启’errors’=>’TRUE’,这会将PHP原生的错误转化的更容易提交.原文 errors into exceptions which are easier to handle.

1. An Improved Exception Handler(三步走之第一步,一个改良的异常捕获方法)

我们常用的异常机制是原生的非友好,自身说明问题的(Kohana的异常机制代码如下,不翻译).原文

  1. class Kohana_Exception extends Kohana_Kohana_Exception {
  3.     public static function handler(Exception $e)
  4.     {
  5.         if (Kohana::DEVELOPMENT === Kohana::$environment)
  6.         {
  7.             parent::handler($e);
  8.         }
  9.         else
  10.         {
  11.             try
  12.             {
  13.                 Kohana::$log->add(Log::ERROR, parent::text($e));
  15.                 $attributes = array
  16.                 (
  17.                     'action'  => 500,
  18.                     'message' => rawurlencode($e->getMessage())
  19.                 );
  21.                 if ($e instanceof HTTP_Exception)
  22.                 {
  23.                     $attributes['action'] = $e->getCode();
  24.                 }
  26.                 // Error sub-request.
  27.                 echo Request::factory(Route::get('error')->uri($attributes))
  28.                 ->execute()
  29.                 ->send_headers()
  30.                 ->body();
  31.             }
  32.             catch (Exception $e)
  33.             {
  34.                 // Clean the output buffer if one exists
  35.                 ob_get_level() and ob_clean();
  37.                 // Display the exception text
  38.                 echo parent::text($e);
  40.                 // Exit with an error status
  41.                 exit(1);
  42.             }
  43.         }
  44.     }
  45. }

如果我们在开发环境下就过掉(无视)它,转用其他的Kohana异常处理(机制).原文

记录错误[原文](# Log the error) 设置路由动作函数和信息(属性).[原文](# Set the route action and message attributes.) 如果一个’HTTP_Exception’抛出,就重写动作,显示相关错误代码(当然,是友好).[原文](# If a HTTP_Exception was thrown, then override the action with the error code.) 抛出一个内部子请求.[原文](# Fire off an internal sub-request.)

动作会被当作HTTP response代码.默认的是500(服务器错误),除非一个’HTTP_Response_Exception’抛出.原文 unless a HTTP_Response_Exception was thrown.)

因此这个(如下的代码):原文

  1. throw new HTTP_Exception_404(':file does not exist', array(':file' => 'Gaia'));

会显示一个友好的404错误页,这个(如下代码):原文

  1. throw new Kohana_Exception('Directory :dir must be writable',
  2.             array(':dir' => Debug::path(Kohana::$cache_dir)));

将显示一个500错误页面.原文

The Route(路由配置) Route::set(‘error’, ‘error/(/)’, array(‘action’ => ‘[0-9]++’, ‘message’ => ‘.+’)) ->defaults(array( ‘controller’ => ‘error_handler’ ));

2. The Error Page Controller (三步之第二步,错误页面控制器)

  1. public function before()
  2. {
  3.     parent::before();
  5.     $this->template->page = URL::site(rawurldecode(Request::$initial->uri()));
  7.     // Internal request only!
  8.     if (Request::$initial !== Request::$current)
  9.     {
  10.         if ($message = rawurldecode($this->request->param('message')))
  11.         {
  12.             $this->template->message = $message;
  13.         }
  14.     }
  15.     else
  16.     {
  17.         $this->request->action(404);
  18.     }
  20.     $this->response->status((int) $this->request->action());
  21. }

1设置模板显示变量’page’是为了让用户明白自己的请求是什么.这样做的目仅为了显示.原文 2.如果只是内部请求,给’message’变量赋值并显示给用户.原文 3.否则的话使用404动作.用户可以更巧妙的设置自己的信息,比如’error/404/email%20your%20login%20information%20to%20hacker%40google.com'.[原文](#3. Otherwise use the 404 action. Users could otherwise craft their own error messages, eg:error/404/email%20your%20login%20information%20to%20hacker%40google.com`)

  1.     public function action_404()
  2.     {
  3.         $this->template->title = '404 Not Found';
  5.         // Here we check to see if a 404 came from our website. This allows the
  6.         // webmaster to find broken links and update them in a shorter amount of time.
  7.         if (isset ($_SERVER['HTTP_REFERER']) AND strstr($_SERVER['HTTP_REFERER'], $_SERVER['SERVER_NAME']) !== FALSE)
  8.         {
  9.             // Set a local flag so we can display different messages in our template.
  10.             $this->template->local = TRUE;
  11.         }
  13.         // HTTP Status code.
  14.         $this->response->status(404);
  15.     }
  17.     public function action_503()
  18.     {
  19.         $this->template->title = 'Maintenance Mode';
  20.     }
  22.     public function action_500()
  23.     {
  24.         $this->template->title = 'Internal Server Error';
  25.     }

你应注意到每个方法都是在’HTTP response’ 代码后命名,并设置请求的代码.原文

3. Conclusion (三步走之第三步,结局)

搞定!现在显示一个友好的错误页面是相当容易的啦(就像下面这样):原文

  1. throw new HTTP_Exception_503('The website is down');(这会抛出503错误,内容是,站点挂了.)