Symfony\Component\Serializer\Serializer::serialize PHP Method

    public final function serialize($data, $format)
    {
        if (!$this->supportsSerialization($format)) {
            throw new UnexpectedValueException('Serialization for the format '.$format.' is not supported');
        }

        $encoder = $this->getEncoder($format);

        if (!$encoder instanceof NormalizationAwareInterface) {
            $data = $this->normalize($data);
        }

        return $this->encode($data, $format);
    }

 function get(Request $req)
 {
     $resourceName = $req->get('resource');
     if (!isset($this->module["resourceEntityMappings"][$resourceName])) {
         throw new NotFoundHttpException();
     }
     $entityClass = $this->module["namespace"] . $this->module["resourceEntityMappings"][$resourceName];
     // Filterer entities queried?
     if ($req->getQueryString() != null) {
         $querystring = $req->getQueryString();
         $criteria = array();
         $queryParts = \explode('&', $querystring);
         foreach ($queryParts as $queryPart) {
             $key_value = \explode('=', $queryPart);
             $criteria[$key_value[0]] = urldecode($key_value[1]);
         }
         $entities = $this->em->getRepository($entityClass)->findBy($criteria);
         // Single entity queried?
     } elseif ($req->get('id') != null) {
         $id = $req->get('id');
         $entity = $this->em->getRepository($entityClass)->find($id);
         $entities = array($entity);
     } else {
         $entities = $this->em->getRepository($entityClass)->findAll();
     }
     return new Response($this->serializer->serialize(array($resourceName => $entities), 'json'), 200, array('Content-Type' => $req->getMimeType('json')));
 }