Symfony2 Controller won't catch exception

This is the route handler for my delete action. It works well as long as the item does not have any associations.

public function projectDeleteAction()
{
    try {
        $request = $this->get('request');
        $my_id = $request->query->get('id');

        $em = $this->get('doctrine.orm.entity_manager');

        $item = $em->find('MyBundle:Main', $my_id);

        $em->remove($item);
        $em->flush();

        $info = $item->getName();
        $result = 0;
    }
    catch (Exception $e) {
        $info = toString($e);
        $result = -1;
    }

    return $this->render('MyBundle:Main:response.xml.twig',
            array('info' => $info, 'result' => $result ));
}

I have already solved the error of trying to delete an item with associations, but through this process, the "flush" was throwing PDOException. I tried various ways to catch it, but it appears to be getting caught inside Symfony2 and then it responds with a HTTP 500 error. Is there a way that I can have Symfony2 not catch this so that I can handle it? This is an XML response using AJAX and so I would rather just send a开发者_如何学运维n error code per above.

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Try to change Exception → \Exception if you didn't specified PDOException as Exception in a use statement. PHP tries to find \YourNamespaceWithController\Exception instead of \Exception (and it does not check the existence of such exception).

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It is better to catch the exception you really want to catch. In this example that is probably Doctrine/DBAL/DBALException and/or Doctrine/DBA/DBAException.

Thus

catch (Doctrine\DBAL\DBALException $e) {
  $result = -1;
};

I would recomment doing something like:

    } catch (\Exception $e) {
        switch (get_class($e)) {
            case 'Doctrine\DBAL\DBALException':
                echo "DBAL Exception<br />";
                break;
            case 'Doctrine\DBA\DBAException':
                echo "DBA Exception<br />";
                break;
            default:
                throw $e;
                break;
        }
    }

This actually catches the DB exceptions, and if for some reason some other exception occures, this is rethrown back into Symfony2.

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I had to do the following which might help for some users;

try{
    $this->doctrine->em->persist($user);
    $this->doctrine->em->flush();
}catch(Exception $e){
    if($e->getPrevious()->getCode() == 23505){
        //handle duplicate error, 23505 is for postgres, 23000 is mysql unique constraint.    
    }
}