I have a listener service. I want to read some config parameters inside it.
How can I access the service container within the listener class?
2 Answers
You can pass container parameters into your service by using the %your_param_name% notation:
services:
kernel.listener.locale_listener:
class: My\BundleName\Listener\LocaleListener
tags:
- { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }
arguments: [ @router, @service_container, %your_param_name% ]
which will present itself as (in this example) the 3rd argument in your service's constructor method:
public function __construct($router, $container, $paramValue)
{
// ...
}
3 Comments
Phill Pafford
Is there a little more documentation on this? I also have a Listener as a service. In my config.yml I have some settings I wish to access in the Listener, should I configure them as arguments?
Naroh
Please note that since Symfony 2.8 you have to quote those arguments: arguments: [ "@router", "@service_container", "%your_param_name%" ]
Thomas Urban
Doesn't work for me or at least with a FilterResolveEvent dispatched on behalf of kernel.response event in Symfony 4. The constructor is kept invoked with 0 arguments resulting in an exception. Searching the web doesn't give a clue but several outdated matches here at SO or in blogs just repeating that part of the truth that's in the official Symfony tutorial as well. Sorry, but this whole framework is a mess ... is there any official documentation page explaining all this "put arguments with % or @ in YAML so Event Listeners get an argument in constructor accordingly"?
Resolved: We need to pass the @service_container itself as an argument to the listener service
MyBundleName/Resources/services.yml:
services:
kernel.listener.locale_listener:
class: My\BundleName\Listener\LocaleListener
tags:
- { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }
arguments: [ @service_container ]
Listener Class:
class LocaleListener
{
protected $container;
public function __construct(\Symfony\Component\DependencyInjection\Container $container)
{
$this->container = $container;
}
..
public function Myfunction()
{
$languages = $this->container->getParameter('languages');
}
}
4 Comments
Elnur Abdurrakhimov
Passing the whole container in this case is a Bad Idea™.
Robin Barnes
@Elnur - Why is passing the whole container a bad idea?
Elnur Abdurrakhimov
@Robin, because dependencies should be explicit and easy mockable for testing. Also, making your classes aware of the DIC ties them to a particular of DIC. Not good, not good.
Mrquestion
Don't use FQDN!!