Symfony 4.2 - How to decorate the UrlGenerator

Question

I want to decorate the Symfony UrlGenerator class.

Symfony\\Component\\Routing\\Generator\\UrlGenerator: ~

my.url_generator:
    class: AppBund         


        

Answer 1

I believe the issue is that UrlGenerator service name is Symfony\Component\Routing\Generator\UrlGeneratorInterface, and not Symfony\Component\Routing\Generator\UrlGenerator (cf. this code).

Secondly, when you decorate a service, the decorator will take the service name. So you should not need to modify router.options.generator_class.

Try with this configuration:

my.url_generator:
    class: AppBundle\Service\UrlGenerator
    decorates: Symfony\Component\Routing\Generator\UrlGeneratorInterface
    arguments: ['@my.url_generator.inner']

Setting public to false is likely not needed, as on Symfony4/Flex it should be the default value.

Update for comments: decorated service may look like this:

class MyUrlGenerator implements UrlGeneratorInterface
{
    private $originalUrlGenerator;

    public function __construct(UrlGeneratorInterface $innerUrlGenerator)
    {
        $this->originalUrlGenerator = $innerUrlGenerator;
    }

    public function generate($name, $parameters = [], $referenceType = self::ABSOLUTE_PATH)
    {
        // Maybe add your custom logic here... 
        // or completely override base method

        return $this->originalUrlGenerator->generate($name, $parameters, $referenceType);
    }
}