Transform entity for smaller output - php

Question

I am trying to create a simple calendar using Symfony. For this I want to request the events of the selected month via AJAX. Each event can have multiple users connected to it.
Now retrieving the event is quite simple
$events = $this->em->getRepository('AppBundle:Event')
->findByYearMonth($this->getUser(), $year, $month);
$encoder = new JsonEncoder();
$normalizer = new ObjectNormalizer();
$normalizer->setCircularReferenceHandler(function ($object) {
return $object->getId();
});
$serializer = new Serializer([$normalizer], [$encoder]);
$serialized = $serializer->serialize($events, 'json');
$response = new Response($serialized);
$response->headers->set('Content-Type', 'application/json');
I needed to setCircularReferenceHandler because obviously users have the events connected to them as well.
In my test I currently have only 2 events, yet I get a response of ~50kb, simply because it gets bloated by the user objects. All I really want is user ID and name, but it retrieves all other fields (and other connected entities).
The circular reference handler itself only gets active once the user is already returned (and catches the event within the user that originally retrieved the user).
I have already searched about this but did not find a single result that went in the way I wanted to (most were about forms, general serialization, etc).
The only idea I had was adding a method to the Event entity, eg getSimple where I manually set some parameters and leave outers out (but have to do so for everything connected as well). This seemed quite unclean, hence I am asking here.
TL;DR
I want something like
[
{"id":1, "name":"foo", "users":[
{"id":1, "name":hans"},
{"id":2, "name":"jack"},...
]},...
]
but I get something like
[
{"id":1, "name":"foo", "users":[
{"id":1, "name":hans", "events":[1,{"id":3, "name":"this hasnt already been shown"}], "userfield":"var", "anotheruserfield":"bar", "someOtherRelation":{"bla"},
{"id":2, "name":"jack", "events":[1,{"id":3, "name":"this hasnt already been shown"}], "userfield":"var", "anotheruserfield":"bar", "someOtherRelation":{"bla"}},...
]},...
]

Answer 1

If I correctly understand, you want to exclude the events property (and maybe others) from your objects serialization.
The JMSSerializer would fits your needs as it allows to exclude/expose properties and/or limit their depth.
The bundle is mentioned at the end of the Serialization chapter of the Symfony documentation.
See exclusion strategies and its #Exclude, #Expose, #Groups and #MaxDepth annotations.

Answer 2

Yes, JMSSerializer provides Exclude and other methods which might solve this, but I decided for something different: Writing a custom EventNormalizer which does exactly what I want and doesn't change the other entities per se.
$encoder = new JsonEncoder();
$normalizer = new \AppBundle\Serializer\Normalizer\EventNormalizer();
$serializer = new Serializer([$normalizer], [$encoder]);
$serialized = $serializer->serialize($events, 'json');
And the normalizer
namespace AppBundle\Serializer\Normalizer;
use Symfony\Component\Serializer\Normalizer\NormalizerInterface;
/**
* Event normalizer
*/
class EventNormalizer implements NormalizerInterface
{
/**
* {#inheritdoc}
*/
public function normalize($object, $format = null, array $context = array())
{
$result = /* using fields from $object */
return $result;
}
/**
* {#inheritdoc}
*/
public function supportsNormalization($data, $format = null)
{
return $data instanceof \AppBundle\Entity\Event;
}
}