php - Replacing the Translator service in Symfony 3

Question

In my Symfony 2.8 project I have an extension that adds some extra logic to the trans method:

parameters:
    translator.class: MyBundleTwigTranslationExtension

The class looks like this:

namespace MyBundleTwigTranslationExtension;

use SymfonyBundleFrameworkBundleTranslationTranslator as BaseTranslator;

class TranslationExtension extends BaseTranslator
{
    private $currentLocale;

    public function trans($id, array $parameters = array(), $domain = null, $locale = null)
    {
            $translation = parent::trans($id, $parameters, $domain, $locale);

            // Some extra logic here

            return $translation;
    }

    public function transChoice($id, $number, array $parameters = array(), $domain = null, $locale = null)
    {
        return parent::transChoice($id, $number, $parameters, $domain, $locale);
    }
}

Now, I'm migrating to Symfony 3, where those class parameters are deprecated, but how can I implement this by overwriting the translator service?

Answer 1

Instead of extending, it would be better to decorate the translator service. Right now you overriding the class name, which will also override other bundles that want to decorate the service. And I see you made it an extension because of Twig, the original Twig {{ trans() }} filter will use the decorated service too.

services:
  app.decorating_translator:
    class:     AppBundleDecoratingTranslator
    decorates: translator
    arguments: ['@app.decorating_translator.inner'] # original translator
    public:    false

See documentation about decorating here: http://symfony.com/doc/current/service_container/service_decoration.html