How do you call a Service outside of a Symfony3 controller? And queries from Repository - symfony-forms

Question

I have two questions today. This is detailed because too many other replies rely on assumptions and have not been detailed enough. I hope that this is detailed and will be able to help lots of developers.
1st. The code below points to the real question I have. How do you call a Service outside of the controller since the $this->get() method is inside of the controller only? This is not in any of the documentation or on KNP University's tutorial on Services.
2nd. From what I have read, according to some, not all, if you call to a Repository, from anywhere, it should automatically instantiate the Entity Repository. I don't think this is so. Tell me if I am right or wrong.
See the following below....
My Default Controller, it's straightforward call a class and let it do some work. As an example, I called it with a Service and a conventional OO method:
<?php
// src/AppBundle/Controller/DefaultController.php
// Here is where I am starting. There is a service
// and there is a conventional OO call.
// Both should invoke the same thing.
namespace AppBundle\Controller;
use AppBundle\Service;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;
class DefaultController extends Controller
{
/**
* #Route("/", name="homepage")
*/
public function indexAction(Request $request)
{
// Step 1.... Do a little of this.
// Step 2.... Do some of that.
// Step 3.... Call another class to do some logic and it will
// eventually call a query...
// Invoking my service
$obj_via_service = $this->get('app.services.process_question');
$result1 = $obj_via_service->submitQuestion();
// Invoking via Namespace and Call
$obj_via_new = new Service\ProcessQuestion();
$result2 = $obj_via_new->submitQuestion();
dump($result1);
dump($result2);
die();
}
}
My Service.yml File.
# src/app/config/services.yml
parameters:
services:
app.services.process_question:
class: AppBundle\Service\ProcessQuestion
app.rep.geo_state:
class: AppBundle\Entity\GeoStateRepository
arguments: ['#doctrine.orm.entity_manager']
This is my class that is doing the work for me. I want to be able to call the second service ^^above^^ but I can't because I can't use $this->get() outside of the controller.
<?php
// src/AppBundle/Service/ProcessQuestion.php
namespace AppBundle\Service;
class ProcessQuestion
{
public function submitQuestion()
{
// Step 1.... Do this.
// Step 2.... Do that.
// Step 3.... Query for some data...
// Invoke my repository class via a Service Call....
// but I cannot do that because 'get' is a part of the
// controller...
$obj_via_service = $this->get('app.rep.geo_state');
**^^ ^^**
**^^ This is what won't work ^^**
$results = $obj_via_service->selectStates();
return $results;
}
}
My Repository Class... Keep in mind I cannot reach this class yet, but I am throwing it in here so that other new Symfony 3 developers can see this.
<?php
// src/AppBundle/Repository/GeoState.php
// My Repository Class where I want to do some queries...
namespace AppBundle\Repository;
use Doctrine\ORM\EntityRepository;
class GeoStateRepository extends EntityRepository
{
/**
* #Mapping\Column(type="string")
*/
private $em;
public function __construct(EntityManager $em)
{
$this->em = $em;
}
public function selectStates()
{
$sql = "SELECT * FROM geo_state";
return $this->getEntityManager()->createQuery($sql)->getResult();
}
}
Why is this so hard to find an example? Also, I have followed a bunch of the Symfony 2.x documentation and the nuances are hard to port into Symfony 3 sometimes.
I think Fabian re purposed too much of the docs for 2.x to go into 3.x and there is not any good examples on coding that is between the New Developer level and the Hard Core Developer level. If you are at Sensio and reading this, please keep in mind that there is a middle ground we need to cover and most of the screencasts that out there and much of the better documentation is not in English.

Answer 1

You should really read more about Dependency Injection.
Symfony is very good at this .
Regarding your question about using app.rep.geo_state service in the app.services.process_question service .
In Symfony/ DI terminology it's can be termed as injecting a service into another service .
The documentation on how to do this is very good.
this is how it can be done.
services:
app.services.process_question:
class: AppBundle\Service\ProcessQuestion
arguments: ['#app.rep.geo_state']
app.rep.geo_state:
class: AppBundle\Entity\GeoStateRepository
arguments: ['#doctrine.orm.entity_manager']
And in the class
<?php
// src/AppBundle/Service/ProcessQuestion.php
namespace AppBundle\Service;
use AppBundle\Entity\GeoStateRepository;
class ProcessQuestion
{
private $geoRepository;
public function __construct(GeoStateRepository $geoRepository)
{
$this->geoRepository = $geoRepository;
}
public function submitQuestion()
{
//now you can call $this->geoRepository
}
}
Also note that $this->get() is only a shortcut function provided by the Symfony base Controller class to access the container.
To know more about DI, you can read Fabian's excellent articles about this in his blog .