inanzzz | Logging user's master and system's sub request with event listener

With the event listener below, we're going to see what actions cause master and sub requests throughout the system. I've listed some of them below but I guess this list can be extended more.

Request types

Master

External requests that directly come from the user action.

Refreshing the page.

All GET, POST, DELETE, PUT, PATCH etc. requests.

Redirecting with $this->redirect() and return new Symfony\Component\HttpFoundation\RedirectResponse() actions.

Returning normal response with return new Symfony\Component\HttpFoundation\Response() class or other classes/methods.

Sub

Internal requests that does not come from the user action.

Forwarding with controller's $this->forward() helper method.

Forwarding with HttpKernel's forward() method.

Using {% render ... %} in twig templates.

Rendering twig template with controller's return $this->render() helper method.

Parameters.yml

parameters:
    listener.log.file: '%kernel.logs_dir%/listener.log'

# football/app/logs/listener.log

Listeners.yml

services:
    application_backend.listener.user_controller:
        class: Application\BackendBundle\EventListener\UserControllerListener
        arguments:
            - %listener.log.file%
        tags:
            - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }

UserControllerListener.php

namespace Application\BackendBundle\EventListener;

use Symfony\Component\HttpKernel\Event\GetResponseEvent;

class UserControllerListener
{
    private $logFile;
    private $message = [
        true => 'Master request',
        false => 'Sub request'
    ];

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

    public function onKernelRequest(GetResponseEvent $event)
    {
        $this->logRequest(
            $this->message[$event->isMasterRequest()],
            $event->getRequest()->getMethod()
        );
    }

    private function logRequest($message, $method = null)
    {
        file_put_contents(
            $this->logFile,
            file_exists($this->logFile)
                ? file_get_contents($this->logFile) . "\n" . $method . ':' . $message
                : $method . ':' . $message
        );
    }
}

Listener.log

GET:Master request
GET:Sub request
GET:Master request
POST:Master request
GET:Master request
GET:Sub request
GET:Sub request
GET:Master request
GET:Master request
GET:Sub request
GET:Master request