Symfony, who knows how to map a value from a Request?

Question

symfony

Good evening!

services:
    # default configuration for services in *this* file
    _defaults:
        autowire: true      # Automatically injects dependencies in your services.
        autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.
        bind:
            $images_directory: '%app.images_directory%'
            $lang: '%blabalabla%' # Господа, обратите внимание!

Note that $lang will appear as an argument in the controller or service.
My question is how to map the value from Request to this variable?

method in the controller.

... 
  public function add(Request $request, EntityManagerInterface $manager, $lang)
  ...

Answer 1

In general, no way.
Workaround: via value object:

class Locale
{
    /**
     * @var string
     */
    private $value;

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

    public function __toString()
    {
        return $this->value;
    }
}

class LocaleFactory
{
    /**
     * @var RequestStack
     */
    private $requestStack;

    /**
     * @var string
     */
    private $default;

    public function __construct(RequestStack $requestStack, string $default)
    {
        $this->requestStack = $requestStack;
        $this->default = $default;
    }

    public function create(): Locale
    {
        if ($request = $this->requestStack->getMasterRequest()) {
            return new Locale($request->get('locale', $this->default));
        }

        return new Locale($this->default);
    }
}

services:
    App\Locale\Locale:
        factory: ['@App\Locale\LocaleFactory', 'create']

Accordingly, use not as a scalar value

public function add(Request $request, EntityManagerInterface $manager, Locale $lang)

Action Argument Resolver / ParamConverter is also an option, but will only work for controllers.