Symfony: Decorating a service when user has x role

Question

I have been looking for an answer to this question, but I can not seem to find it anywhere.

I have currently defined a decorator service that decorates the translator service. I however want to decorate the translator service only when the user has a certain role.

services.yml

services:
    app.my_translator_decorator:
        class: MyBundle\MyTranslatorDecorator
        decorates: translator
        arguments: ['@app.my_translator_decorator.inner']
        public:    false

MyTranslatorDecorator.php

class MyTranslatorDecorator {

    /**
     * @var TranslatorInterface
     */
    private $translator;

    /**
     * @param TranslatorInterface $translator
     */
    public function __construct(TranslatorInterface $translator)
    {
        $this->translator = $translator;
    }

    // more code...

}

Answer 1

The container is "compiled" before the runtime. You can't decorate a service depending of the context, it will always be decorated.

However, in your decorator, you can add a guard clause to not execute your custom code if not necessary.

Service definition:

services:
    app.my_translator_decorator:
        class:     AppBundle\MyTranslatorDecorator
        decorates: translator
        arguments: ['@app.my_translator_decorator.inner', '@security.authorization_checker']
        public:    false

Decorator:

<?php

namespace AppBundle;

use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
use Symfony\Component\Translation\TranslatorInterface;

class MyTranslatorDecorator implements TranslatorInterface
{
    private $translator;
    private $authorizationChecker;

    public function __construct(TranslatorInterface $translator, AuthorizationCheckerInterface $authorizationChecker)
    {
        $this->translator = $translator;
        $this->authorizationChecker = $authorizationChecker;
    }

    public function trans($id, array $parameters = [], $domain = null, $locale = null)
    {
        if (!$this->authorizationChecker->isGranted('ROLE_ADMIN')) {
            return $this->translator->trans($id, $parameters, $domain, $locale);
        }

        // return custom translation here
    }

    // implement other methods
}