How to inject a service in another service in Symfony? - php

Question

I am trying to use the logging service in another service in order to trouble shoot that service.
My config.yml looks like this:
services:
userbundle_service:
class: Main\UserBundle\Controller\UserBundleService
arguments: [#security.context]
log_handler:
class: %monolog.handler.stream.class%
arguments: [ %kernel.logs_dir%/%kernel.environment%.jini.log ]
logger:
class: %monolog.logger.class%
arguments: [ jini ]
calls: [ [pushHandler, [#log_handler]] ]
This works fine in controllers etc. however I get no out put when I use it in other services.
Any tips?

Answer 1

You pass service id as argument to constructor or setter of a service.
Assuming your other service is the userbundle_service:
userbundle_service:
class: Main\UserBundle\Controller\UserBundleService
arguments: [#security.context, #logger]
Now Logger is passed to UserBundleService constructor provided you properly update it, e.G.
protected $securityContext;
protected $logger;
public function __construct(SecurityContextInterface $securityContext, Logger $logger)
{
$this->securityContext = $securityContext;
$this->logger = $logger;
}

Answer 2

For Symfony 3.3, 4.x, 5.x and above, the easiest solution is to use Dependency Injection
You can directly inject the service into another service, (say MainService)
// AppBundle/Services/MainService.php
// 'serviceName' is the service we want to inject
public function __construct(\AppBundle\Services\serviceName $injectedService) {
$this->injectedService = $injectedService;
}
Then simply, use the injected service in any method of the MainService as
// AppBundle/Services/MainService.php
public function mainServiceMethod() {
$this->injectedService->doSomething();
}
And viola! You can access any function of the Injected Service!
For older versions of Symfony where autowiring does not exist -
// services.yml
services:
\AppBundle\Services\MainService:
arguments: ['#injectedService']

Answer 3

More versatile option, is to once create a trait for the class you would want to be injected. For instance:
Traits/SomeServiceTrait.php
Trait SomeServiceTrait
{
protected SomeService $someService;
/**
* #param SomeService $someService
* #required
*/
public function setSomeService(SomeService $someService): void
{
$this->someService = $someService;
}
}
And where you need some service:
class AnyClassThatNeedsSomeService
{
use SomeServiceTrait;
public function getSomethingFromSomeService()
{
return $this->someService->something();
}
}
The class will autoload due to #required annotation. This generaly makes it much faster to implement when you want to inject services into numerous classes (like event handlers).