Added cookbook entry about turning a Doctrine repository into a service

cookbook/doctrine/repository_service.rst

@@ -0,0 +1,96 @@
+How to turn your Doctrine repository into a service
+===================================================
+
+Working with repositories can be a pretty messy task. Sometimes it is more
+logic to perform certain things right in the repository instead of pulling
+the data and handle it in other places.
+Since this often requires to have other services at hand it is a good
+idea to turn your standard Doctrine repository into a service.
+
+Let's start with the repository itself. The process is pretty straight forward:
+if you might need to log something, here is the how-to too:
+
+<?php
+
+namespace Acme\BlogBundle\Entity\Repository;
+
+use Psr\Log\NullLogger;
+use Psr\Log\LoggerInterface;
+use Doctrine\Common\Persistence\Mapping\ClassMetadata;
+use Doctrine\ORM\EntityRepository;
+use Doctrine\ORM\EntityManager;
+
+class PostRepository extends EntityRepository
+{
+private $Logger; /** @var LoggerInterface */
+
+/**
+ *
+ * @param EntityManager $em
+ * @param ClassMetadata $class
+ */
+public function __construct(EntityManager $em, ClassMetadata $class)
+{
+parent::__construct($em, $class);
+
+$this->Logger = new NullLogger();
+}
+
+/**
+ *
+ * @param LoggerInterface $logger
+ */
+public function setLogger(LoggerInterface $logger)
+{
+$this->Logger = $logger;
+}
+ }
+
+ // ...
+
+Proceed with creating the service definition:
+
+ .. code-block:: xml
+<container xmlns="http://symfony.com/schema/dic/services"
+ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://symfony.com/schema/dic/services/services-1.0.xsd">
+<services>
+ <service id="acme.blog.repository.event"
+ class="Acme\BlogBundle\Entity\Repository\PostRepository"
+ factory-service="doctrine.orm.entity_manager"
+ factory-method="getRepository">
+ <argument>Acme\BlogBundle\Entity\Blog</argument>
+
+ <call method="setLogger">
+<argument type="service" id="logger" />
+ </call>
+ </service>
+ </services>
+</container>
+
+Finally, use your repository in your standard controller:
+
+<?php
+
+namespace Acme\BlogBundle\Controller;
+
+use Symfony\Bundle\FrameworkBundle\Controller\Controller;
+use Acme\BlogBundle\Entity\Post;
+use Acme\BlogBundle\Entity\Repository\PostRepository;
+
+class PostController extends Controller
+{
+ public function indexAction()
+ {
+	/* @var $repository PostRepository */
+	$repository = $this->get('acme.blog.repository.post');
+ $entities = $repository->findAll();
+
+ return $this->render('AcmeBlogBundle:Blog:index.html.twig', array(
+ 'entities' => $entities
+ ));
+ }
+
+ // ...
+}
+