How to stop Symfony project execution from a filter

When you need to stop execution of your project from a Symfony filter, for example, when you’re checking all requests to your application for some correct GUID, you need to do one simple thing:

[php]
<?php
/**
* Checks the GUID and allow/deny the request
*/
class sfCheckGUIDFilter extends sfFilter
{

public function execute($filterChain)
{
$sfContext = $this->getContext();
if ($this->isGUIDCorrect($sfContext->getRequest()->getParameter(‘GUID’))) {
$filterChain->execute();
} else {
$response = $sfContext->getResponse();
$response->setStatusCode(403);
$response->setHttpHeader(‘Content-Type’, ‘text/plain’, true);
$response->setContent(‘Not allowed’);
$response->sendContent();
}
}

private function isGUIDCorrect($guid) {
// TODO: implement your GUID checker
}
}
[/php]

and in the filters.yml file of your application you just add this filter in a following way:

[php]
# You can find more information about this file on the symfony website:
# http://www.symfony-project.org/reference/1_4/en/12-Filters

rendering: ~
security: ~

# insert your own filters here
guid_checker:
class: sfCheckGUIDFilter

cache: ~
execution: ~
[/php]

In this case this filter is used for entire application. When you need to cover with checker only few actions please use other ways, like preExecute method of an Action.