Symfony2. Getting service in template.

MyBundle\Service\Catalog.php

<?php

namespace MyBundle\Service;

class Catalog
{
    protected $em;

    public function __construct($em)
    {
        $this->em = $em;
    }

    public function getItems()
    {
        if(!isset($this->items))
            $this->items = $this->em->getRepository('MyBundle:Item')->findAll();

        return $this->items;
    }
}

MyBundle\Templating\Catalog

<?php

namespace MyBundle\Templating\Catalog;

use MyBundle\Service\Catalog as CatalogService;
use Symfony\Component\Templating\Helper\Helper;

class Catalog extends Helper
{
    protected $catalog;

    public function __construct(CatalogService $cs)
    {
        $this->catalog = $cs;
    }

    public function getItems()
    {
        return $this->catalog->getItems();
    }

    public function getName()
    {
        return 'catalog';
    }
}

services.yml

services:
  catalog:
    class:                          MyBundle\Service\Catalog
    arguments:
      services:
        em:                         '@doctrine.orm.entity_manager'
  helper.catalog:
    class:                          MyBundle\Templating\Catalog
    arguments:
      catalog_service:               '@catalog'
    tags:
      - { name: templating.helper, alias: catalog }

template.html.php

<ul>

<?php foreach($view['catalog']->getItems() as $item): ?>

    <li>
        <?php echo $item->getTitle() ?>
    </li>

<?php endforeach ?>

</ul>