Service declaration in yml for http://marvelley.com/2012/12/20/symfony2-json-responses-for-xhr-errors-and-authentication-failures/

json.response.xhr.symfony

# http://marvelley.com/2012/12/20/symfony2-json-responses-for-xhr-errors-and-authentication-failures/
parameters:
     acme.demo.xhr_core_exception_listener.class: Acme\DemoBundle\Listener\XHRCoreExceptionListener
     acme.demo.xhr_authentication_success_handler.class: Acme\DemoBundle\Handler\XHRAuthenticationSuccessHandler
     acme.demo.xhr_authentication_failure_handler.class: Acme\DemoBundle\Handler\XHRAuthenticationFailureHandler
     options:
     
services:
    acme.demo.xhr_core_exception_listener:
        class: "%acme.demo.xhr_core_exception_listener.class%"
        tags:
            - {name: kernel.event_listener, event: kernel.exception, priority: 1000}

    acme.demo.xhr_authentication_success_handler:
        class: "%acme.demo.xhr_authentication_success_handler.class%"
        arguments: ['@security.http_utils', "%options%"]

    acme.demo.xhr_authentication_failure_handler:
        class: "%acme.demo.xhr_authentication_failure_handler.class%"
        arguments: ['@http_kernel','@security.http_utils', "%options%", '@?logger']