Overriding Symfony 2 exceptions?

You should create a listener that listens on kernel.exception event. In onKernelException method of that listener you can check for your exception e.g

On exception listener class

  //namespace declarations  class YourExceptionListener  {      public function onKernelException(GetResponseForExceptionEvent $event)      {        $exception =  $event->getException();        if ($exception instanceof YourException) {            //create response, set status code etc.            $event->setResponse($response); //event will stop propagating here. Will not call other listeners.        }      }  }

The service declaration would be

 //services.yml kernel.listener.yourlisener:  class: FQCN\Of\YourExceptionListener  tags:    - { name: kernel.event_listener, event: kernel.exception, method: onKernelException }

Bellow is part of my AppKernel.php for disabling internal Exception catch by Symfony for JSON requests, (you can override handle method instead of creating second one)

use Symfony\Component\HttpFoundation\Request;use Symfony\Component\HttpKernel\HttpKernelInterface;use Symfony\Component\HttpKernel\Kernel;use Symfony\Component\Config\Loader\LoaderInterface;class AppKernel extends Kernel {  public function init() {    parent::init();    if ($this->debug) {      // workaround for nasty PHP BUG when E_STRICT errors are reported      error_reporting(E_ALL);    }  }  public function handleForJson(Request $request,                                $type = HttpKernelInterface::MASTER_REQUEST,                                $catch = true  ) {    return parent::handle($request, $type, false);  }  ...