Get EntityManager in Helper Class - symfony

Question

I´m using Symfony 2.1, I have this controller:
<?php
namespace app\UsuariosBundle\Controller;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Request;
use app\UsuariosBundle\Entity\Usuarios;
use app\ClientesBundle\Entity\Clientes;
use app\UsuariosBundle\Util\Util;
class DefaultController extends Controller
{
//Some functions
public function conexionAction(Request $request){
$util=new Util();
$sesion=$util->compruebaSesion(1,1,1);
}
}
?>
And this is my helper class, his folder is in UsuariosBundle\Util\Util.php
<?php
namespace app\UsuariosBundle\Util;
class Util
{
public function compruebaSesion($tipo,$idUsuario,$login){
//Here I need the entity manager
}
}
?>
I need the entity manager to do some updates in the database with the util class from everywhere in the app, but I don´t know how to get the entity manager here,out of the controller.
|-| UPDATE |-|
I have updated my code with the instructions of Vincent T and I´m gettin this error:
"Argument 1 passed to app\UsuariosBundle\Service\Util::__construct() must be an instance of Doctrine\ORM\EntityManager, none given, "
app/config/services.yml
services:
util:
class: app\UsuariosBundle\Service\Util
arguments: ["#doctrine.orm.entity_manager"]
src/UsuariosBundle/Service/Util.php
<?php
namespace app\UsuariosBundle\Util;
use Doctrine\ORM\EntityManager;
class Util
{
protected $em;
public function __construct(EntityManager $em)
{
$this->em = $em;
}
public function compruebaSesion($tipo,$idUsuario,$login){
$query= $this->em->createQuery('some query');
}
}
?>

Answer 1

Create a service as described in the docs sf docs services
and then you can just either inject that as a base service or get it using $this->get('name_of_helper_service') in a controller.
# app/config/services.yml
services:
app.service.util:
class: app\UsuariosBundle\Service\UtilService
arguments: ["#doctrine.orm.entity_manager"]
helper class
<?php
namespace app\UsuariosBundle\Util;
use Doctrine\ORM\EntityManager;
class Util
{
/**
* #Var EntityManager
*/
protected $em;
public function __construct(EntityManager $em)
{
$this->em = $em;
}
public function compruebaSesion($tipo,$idUsuario,$login){
$query= $this->em->createQuery('some query');
}
}
?>
Controller class
<?php
namespace app\UsuariosBundle\Controller;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Request;
use app\UsuariosBundle\Entity\Usuarios;
use app\ClientesBundle\Entity\Clientes;
use app\UsuariosBundle\Util\Util;
class DefaultController extends Controller
{
//Some functions
public function conexionAction(Request $request){
$util= $this->get('app.service.util');
$sesion=$util->compruebaSesion(1,1,1);
}
}
?>