Symfony 4 setter injection in parent class - forms

Question

Just a quick question. I'm building some API. I was thinking about creating simple parent class that would deal with form requests.
So for example if you would like to easily handle form request you just extend this class and you get access to request object, request data extracted from that object and bunch of methods that do some things for you out of the box. It doesn't matter what and why exactly.
The problem is:
I send request through postman.
I try to use request object in class that extends parent class but instead of request I get null.
How do I set up the whole thing?:
Now in Symfony every controller is by default registered as a service so I override this definition like this:
#generic api form controller
App\Controller\Api\ApiFormController:
calls:
- [setDependencies, ['#request_stack', '#App\Service\Serialization\Serializer']]
So as you can see I am using setter injection.
I extend above class in my other class. Let's call it PostController. So:
<?php
namespace App\Controller\Api;
use Symfony\Component\HttpFoundation\RequestStack;
class ApiFormController
{
/**
* #var Request
*/
public $request;
/**
* #param RequestStack $requestStack
*/
public function setDependencies(
RequestStack $requestStack
) {
$this->request = $requestStack;
}
}
And now PostController:
public function get(int $post = null)
{
dump($this->request); exit;
}
I was expecting to get access like this and I think I understand why I don't have access to this object. I'm looking for some ideas how I could achieve this goal in cleanest possible way. I'm not expecting ready answers but hints.
I was thinking about using events to set it up in the background?
I also think it has something to do with the way I'm hooking up my controller as a service.

Answer 1

The core of it all: Symfony does not pick up service definition for subclasses. So if you define dependencies for a class and extend it in another class, you have to define the dependencies for this second class too.
The easiest way is to use the parent keyword for this, so your example would work in the following way:
App\Controller\Api\ApiFormController:
calls:
- [setDependencies, ['#request_stack', '#App\Service\Serialization\Serializer']]
PostController:
parent: App\Controller\Api\ApiFormController

Answer 2

If you are using autowiring, you can use #required to make Symfony call the setter automatically. https://symfony.com/doc/current/service_container/autowiring.html#autowiring-other-methods-e-g-setters
/**
* #param RequestStack $requestStack
* #required
*/
public function setDependencies(
RequestStack $requestStack
) {
$this->request = $requestStack;
}
This should do the trick.

Answer 3

I see several problems here.
If you want to inject dependencies in such a way you should define controller as service. You can read more here.
Routing should be something like this:
# config/routes.yaml
get_something:
path: /
defaults: { _controller: App\Controller\Api\PostController:get }
Also, you should define PostController as service, not ApiFormController.
You injected RequestStack but type hint for the attribute is Request.
Instead of:
$this->request = $requestStack;
You need to use:
$this->request = $requestStack->getMasterRequest();