Remove proxies from Json Response Symfony2 - json

Question

I'm working in Symfony2 application and what I'm trying to do is to remove unwanted fields from response and show only fields that I want.
My JSON looks like this:
[
{
"id": 1,
"title": "Granit",
"typeId": {
"id": 1,
"name": "X or Y",
"acroname": "xory",
"__initializer__": null,
"__cloner__": null,
"__isInitialized__": true
},
"pushDate": {
"timezone": {
"name": "Europe/Berlin",
"location": {
"country_code": "DE",
"latitude": 52.5,
"longitude": 13.36666,
"comments": "most locations"
}
},
"offset": 7200,
"timestamp": 1460584800
},
"addedAt": {
"timezone": {
"name": "Europe/Berlin",
"location": {
"country_code": "DE",
"latitude": 52.5,
"longitude": 13.36666,
"comments": "most locations"
}
},
"offset": 7200,
"timestamp": 1460548644
},
"deviceToShow": {
"id": 2,
"name": "Mobile",
"__initializer__": null,
"__cloner__": null,
"__isInitialized__": true
},
"statusSurvey": false,
"slides": [
{
"id": 1,
"title": "First Question",
"picture1": "160413015724bazinga2.jpg",
"picture2": "160413015724th.jpg",
"idSurvey": 1,
"absolutePathpic1": "C:\\xampp\\htdocs\\stu-wrapper\\src\\AppBundle\\Entity/../../../web/uploads/slideSurvey/160413015724bazinga2.jpg",
"webPathpic1": "uploads/slideSurvey/160413015724bazinga2.jpg",
"absolutePathpic2": "C:\\xampp\\htdocs\\stu-wrapper\\src\\AppBundle\\Entity/../../../web/uploads/slideSurvey/160413015724th.jpg",
"webPathpic2": "uploads/slideSurvey/160413015724th.jpg",
"file": null,
"file1": null
}
],
"categories": []
}
]
I want to remove fields like "initializer": null,"cloner": null, "isInitialized": true and hide timezone object and show only "timestamp".
Here is my controller where I'm doing serializing and creating Json Response.
public function getAction()
{
$em = $this->getDoctrine ()->getManager ();
$survey = $em->getRepository ( 'AppBundle:Survey' )->findAll ();
if ( !$survey ) {
throw $this->createNotFoundException ( 'Data not found.' );
}
$encoder = new JsonEncoder();
$normalizer = new ObjectNormalizer();
$normalizer->setCircularReferenceHandler ( function ( $survey ) {
return $survey->getid ();
} );
$serializer = new Serializer( array ( $normalizer ), array ( $encoder ) );
$jsonContent = $serializer->serialize ( $survey, 'json' );
return new Response( $jsonContent );
}
Thank you.

Answer 1

Try to exclude this fields:
$normalilzer->setIgnoredAttributes(
[
"__initializer__",
"__cloner__",
"__isInitialized__"
]);

Answer 2

Detach entity to remove doctrine2 links to the object
$em->detach($survey);