Error Handling
Introduction
As you all (should) know error handling is a very important part in the development process. Not only does it show the user that the page he/she/it requested is not available, it's also a way to inform machines (browsers and such) about what’s going on by providing a HTTP error status.
Error 404
The 404 route is set in app/config/routes.php and must point to the controller/method that handles the 404 pages. Read more about it in the routing section.
Throwing a 404
There may be times when one needs to throw a 404 error, such as when handling the routing yourself. This is simply done by throwing a HttpNotFoundException. Fuel will exit for you once it has run the 404 page.
throw new HttpNotFoundException;
This exception is caught and processed in your applications index.php file. When caught, it will do a lookup for the defined 404 route, and if found, it will forge a new request using the route found as the URI for the request. As this is a normal request, the URI will be routed like any other request!
If you don't want this behaviour, change your index.php file to read
// Generate the request, execute it and send the output.
try
{
$response = Request::forge()->execute()->response();
}
catch (HttpNotFoundException $e)
{
$route = array_key_exists('_404_', Router::$routes) ? Router::$routes['_404_']->translation : Config::get('routes._404_');
if ($route)
{
// add 'false' to the forge request do disable the routing engine
$response = Request::forge($route, false)->execute()->response();
}
else
{
throw $e;
}
}
404 handling
When a request is made and after the router looked for possible matches and there is no match, the 404 handling comes into play. By default the _404_ route points to welcome/404, let's take a look at that method:
// Inside Controller_Welcome
/**
* The 404 action for the application.
*
* @access public
* @return void
*/
public function action_404()
{
$messages = array('Aw, crap!', 'Bloody Hell!', 'Uh Oh!', 'Nope, not here.', 'Huh?');
$data['title'] = $messages[array_rand($messages)];
// Set a HTTP 404 output header
return Response(View::forge('welcome/404', $data), 404);
}
Here you can see what's going on inside the 404 handler. As you can see it's a normal controller action. What's nice about this is that it allows you to show whatever content you like on the page. You can load your own views with data fetched from a database.
Note that Fuel doesn't set the 404 status, your response must set this. Return Response::forge(ViewModel::forge('welcome/404'), 404); in order to send the correct status header.
Catch all
Because Fuel doesn't set the 404 response status, you can use it as a catch all function. You might have have a page model that can fetch the page from a database by uri. Here is an example to illustrate the possibilities:
// Inside your 404 controller
public function action_my404()
{
$original_uri = \Input::uri();
$result = \DB::select()->from('pages')->where('uri', $original_uri)->execute();
if(count($result) === 1)
{
// display that page in whatever way you like
}
else
{
// display your general 404 page
$messages = array('Aw, crap!', 'Bloody Hell!', 'Uh Oh!', 'Nope, not here.', 'Huh?');
$data['title'] = $messages[array_rand($messages)];
return Response(View::forge('welcome/404', $data), 404);
}
}
Throwing a 500
There may be moments where your applications simply need to stop and show an error to indicate that something has gone wrong on the server. Normally this is a 500 Internal Server Error.
Similar to throwing a 404, one can throw a 500 error.
throw new HttpServerErrorException;