php - How to disable redirection after login_check in Symfony 2

Question

I need to disable redirection after login check, because I need to get only that the login was success or not. After submission /login_check url give me the right data, but keep redirecting to /login (on failure).
/login is blank after that.
I am trying to set up login form using extjs 4 so I need to validate trough an ajax post request. login_check should authenticate, create user session and return whether it was success or failure, but no forwarding anywhere.

my login.html.twig looks like:

{% if is_granted("IS_AUTHENTICATED_REMEMBERED") %}
    { success:true }
{% else %}
    { success: false }
{% endif %}

and in security.yml:

firewalls:
    main:
        form_login:
            provider: fos_userbundle
            failure_path:  null
            failure_forward: false

Answer 1

Create an authentication handler:

namespace YourVendorUserBundleHandler;

// "use" statements here

class AuthenticationHandler
implements AuthenticationSuccessHandlerInterface,
           AuthenticationFailureHandlerInterface
{
    public function onAuthenticationSuccess(Request $request, TokenInterface $token)
    {
        if ($request->isXmlHttpRequest()) {
            $result = array('success' => true);
            return new Response(json_encode($result));
        } else {
            // Handle non XmlHttp request here
        }
    }

    public function onAuthenticationFailure(Request $request, AuthenticationException $exception)
    {
        if ($request->isXmlHttpRequest()) {
            $result = array('success' => false);
            return new Response(json_encode($result));
        } else {
            // Handle non XmlHttp request here
        }
    }
}

Register the handler as a service:

services:
    authentication_handler:
        class: YourVendorUserBundleHandlerAuthenticationHandler

Register the service in the firewall:

firewalls:
    main:
        form_login:
            success_handler: authentication_handler
            failure_handler: authentication_handler

This is a rough example to give you the general idea — you'll need to figure out the details by yourself. If you're stuck and need further clarifications, put your questions in the comments and I'll try to elaborate the example.