Flex : mixing autowiring and old-fashioned service way

Context

Symfony Flex incredibly reduces and simplifies day-to-day Symfony usage. Among other things, autowiring is one of the biggest. But what if you need to use some old-school service naming for further usage ?

Solution

For the CMS bundle I'm working on, I needed to refer to an handler for security (successful/failure authentication). Docs states I can use a service name in security.yaml :

admin:
    provider: db_provider # Use any declared provider above
    form_login:
        login_path: /admin/login
        check_path: /admin/login
        default_target_path: /admin
        username_parameter: login[username_or_email]
        password_parameter: login[password]

        success_handler:    app.security_handler
        failure_handler:    app.security_handler

The handler :

use Symfony\Component\HttpFoundation\RedirectResponse;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\RouterInterface;
use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
use Symfony\Component\Security\Core\Exception\AuthenticationException;
use Symfony\Component\Security\Http\Authentication\AuthenticationFailureHandlerInterface;
use Symfony\Component\Security\Http\Authentication\AuthenticationSuccessHandlerInterface;

class SecurityHandler implements AuthenticationSuccessHandlerInterface, AuthenticationFailureHandlerInterface
{

    private $router;

    public function __construct(RouterInterface $router)
    {
        $this->router = $router;
    }

    public function onAuthenticationSuccess(Request $request, TokenInterface $token)
    {
        // TODO make necessary check to ensure proper redirection after successful authentication   
        return new RedirectResponse($this->router->generate('index'));
    }

    public function onAuthenticationFailure(Request $request, AuthenticationException $exception)
    {
        // TODO make necessary check to ensure proper redirection after failure authen authentication
        return new RedirectResponse($this->router->generate('app_login'));
    }
}

But from a Flex point of view, the constructor with type-hinted arguments is enough.

The solution is in 2 steps

1. Define the service "old-fashioned" way

app.security_handler:
  class: App\Listener\Security\SecurityHandler

But doing so, to core will switch to old way to load service. Meaning that you would have to provide parameters/services for dependancy injection manually.

2. Define a service alias

App\Listener\Security\SecurityHandler: '@app.security_handler'

This very last step enable autowiring for your service. I can use the name in security.yaml as above.