通过 Symfony 中的路由在方法调用之前立即调用另一个方法

Question

I'm very new to Symfony framework and I'm trying to replicate what I usually do with other languages (still following the MVC pattern)

The target is to call InitializeSomething() everytime Fly() is called, immediately before. Here is my code:

<?php
// src/Controller/ExampleController.php
namespace App\Controller;

use App\Common\Utils;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class ExampleController extends BaseController
{
    public function __construct()
    {
      // Initialize vars and so on...
    }

    /**
     * @Route("/example/fly")
     */
    public function Fly()
    {
      // This method is obviously called via the route
    }

    private function InitializeSomething()
    {
      // I would like to call this before Fly() is executed
    }
...

of course the easiest way to reach the result is doing this:

...
    /**
     * @Route("/example/fly")
     */
    public function Fly()
    {
      $this->InitializeSomething();
      ...
    }
...

If there is no other elegant way to do that I will go for that solution, I just would like to avoid to spread all around my code the same method everywhere (the final home for the InitializeSomething method will be in the base class).

Usually with other languages I just call my InitializeSomething inside the constructor, because controller classes are instantiated every time a method is called, but here seems Symfony works in a different way and when constructor is called is too early to make my initialization.

Edit: Thank you for your advices. Here are few examples of what I'm going to do.

    private function InitializeSomething()
    {
      // Add the connection to a local variable, just to have a shortcut and avoid boilerplate
      $this->dbconnection = $this->getEntityManager()->getConnection();
      $this->dbengine = $this->getDoctrine();

      // Engine start
      if($engine==false) {
        SwitchOnEngine();
      }

      if($engine->rpm < 1000) {
        WaitEngineStart();
      }

      // Other things like logging the event and so on

    }

The point is if I forget to initalize the things, something wrong will happen and I want to minimize the errors by letting the machine to intialize the things automatically, once for every class.

Answer 1

Symfony has what we call Events. You can check the documentation but this specific event here is called right before the contoller gets executed: https://symfony.com/doc/current/reference/events.html#kernel-controller-arguments

Here you have the full documentation about the Symfony events component so you can understand how to implement what you need: https://symfony.com/doc/current/event_dispatcher.html

You would end up with something like:

class InitializerListener
{
    public function onKernelController(ControllerEvent $event)
    {
        [$controllerInstance, $actionName] = $this->getController();
        $controllerInstance->initializeSomething();
    }
}

And in your config:

# config/services.yaml
services:
    App\EventListener\InitializerListener:
        tags:
            - { name: kernel.event_listener, event: kernel.controller }

PS.: If your controller has more than one action method, getController returns an array in the format exemplified in the code above. See: https://symfony.com/doc/current/event_dispatcher/before_after_filters.html

Also, don't start your methods with uppercase letters in PHP: https://www.php-fig.org/psr/psr-12/