Symfony2 returns empty JSON on AJAX call while variable isn't empty

Question

Problem

I'm trying to get an AJAX response so I can fiddle around with it to make my forms easier to use. When I make the controller (code below) return a normal response with var_dump(), I get the object's output so I know the query isn't wrong (I'm using ID 1 to query to debug). However, when I return the output with json_encode(), I just get an empty JSON file.

HTML form in the view

<div id="content">
    <form id="myForm" action="{{path('snow_ajax')}}" method="POST" >
        Write your name here:
        <input type="text" name="name" id="name_id" value="" /><br />
        <input type="submit" value="Send" />
    </form>
</div>

Script in the same view

<script type="text/javascript">
    $(document).ready(function() {

        $("#myForm").submit(function(){
            var url=$("#myForm").attr("action");

            $.post(url,{
                formName:"ajaxtest",
                other:"attributes"
            },function(data){

                if(data.responseCode==200 ){
                    alert("Got your json!");
                }
                else{
                    alert("something went wrong :(");
                }
            });
            return false;
        });
    });
</script>

Controller with normal response (works)

public function ajaxAction()
{

    $location = $this->getDoctrine()->getRepository('SnowFrontBundle:Location')
        ->find(1);

    $output = var_dump($location);

    return $output;
}

Controller with AJAX response (doesn't work, returns empty JSON)

public function ajaxAction()
{

    $location = $this->getDoctrine()->getRepository('SnowFrontBundle:Location')
        ->find(1);

    return new Response(json_encode($location), 200);
}

Could anyone help me out here, please? This is driving me nuts!

thomastuts · Accepted Answer · 2013-01-19 11:55:09Z

5

I managed to fix it by using Doctrine2's entity manager to get the result in an array, after which I proceeded to encode it into JSON. I'm not sure if this is the cleanest way to do it (getEntityManager() seems to be deprecated according to my IDE) but it works fine for now.

public function ajaxAction()
{
    $em = $this->getDoctrine()->getEntityManager();
    $query = $em->createQuery('SELECT l FROM Snow\FrontBundle\Entity\Location l WHERE l.id=:id');
    $query->setParameter('id', 1);
    $result = $query->getArrayResult();

    return new Response(json_encode($result), 200);
}

answered Jan 19, 2013 at 11:55

thomastuts

3,5593 gold badges22 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

topaz1008 Over a year ago

json_encode() expects an associative array. you cant directly encode entities. you can use JMS Serializer Bundle if you want to encode entities. I would just create an array with the values you want to encode (since it might not be all the entity's properties)

theunraveler · Accepted Answer · 2013-03-07 05:10:34Z

2

This is happening because json_encode() does not know how to serialize an object (other than StdClass) to JSON. There are at least two ways to solve this:

If you are on PHP 5.4 or above, you can have your object implement JsonSerializable, which PHP will use when you call json_encode() on the object.
If you are on PHP 5.3 or earlier, you can use Symfony's Serializer component to convert the object to JSON using a number of different methods. I won't explain how exactly to do that, since the documentation is pretty clear.

answered Mar 7, 2013 at 5:10

theunraveler

3,28423 silver badges20 bronze badges

Comments

topaz1008 · Accepted Answer · 2013-01-20 08:03:40Z

-1

Code example:

$entity = // Get some entity
$result = array(
    'id' => $entity->getId(),
    'name' => $entity->getName()
);

return new Response(json_encode($result));

answered Jan 20, 2013 at 8:03

topaz1008

2153 silver badges4 bronze badges

Comments

bish · Accepted Answer · 2015-10-20 06:32:03Z

-1

If you want to get back data, you have to use a query repository (dsl) and on your $query variable use the getArrayResult() method. That allows you to get an array directly.

edited Oct 20, 2015 at 6:32

bish

3,4659 gold badges52 silver badges71 bronze badges

answered Oct 20, 2015 at 5:42

MikeLowry

1

Collectives™ on Stack Overflow

Symfony2 returns empty JSON on AJAX call while variable isn't empty

Problem

HTML form in the view

Script in the same view

Controller with normal response (works)

Controller with AJAX response (doesn't work, returns empty JSON)

4 Answers 4

1 Comment

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

Problem

HTML form in the view

Script in the same view

Controller with normal response (works)

Controller with AJAX response (doesn't work, returns empty JSON)

4 Answers 4

1 Comment

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related