JMSSerializerBundle not mapping key equals to 0

Question

i'm using JMSSerializerBundle and i'm noticing a strange behavior with serialization.

I'am using $jsonItems = $serializer->serialize($invoiceItems, 'json'); where $invoiceitems is the following :

array(2) {
  ["services"]=>
  array(3) {
    [1]=>
    array(1) {
      [0]=>
      object(stdClass)#757 (26) {
        ["__CLASS__"]=>
        string(43) "Evo\BackendBundle\Entity\InvoiceItemService"
        ["id"]=>
        int(4)
      }
    }
    [2]=>
    array(0) {
    }
    [3]=>
    array(1) {
      [1]=>
      object(stdClass)#846 (26) {
        ["__CLASS__"]=>
        string(43) "Evo\BackendBundle\Entity\InvoiceItemService"
        ["id"]=>
        int(7)
      }
    }
  }
  ["marchandises"]=>
  array(0) {
  }
}

And I get the following JSON :

{"services"{
    "1":[
        {"realDiscount":0,"id":4,"createdAt":"2014-08-22","description":"test 2","type":1,"totalFlat":75,"discountFlat":0,"discountFlatType":"%","chargedHours":0,"chargedMinutes":0,"hourlyRate":0,"discountHourly":0,"discountHourlyType":"%","chargedQuantity":0,"unitPrice":0,"discountQuantity":0,"discountQuantityType":"%","total":75,"discount":0,"discountType":"%","position":1,"chargedTime":0}
    ],
    "2":[],
    "3":{
        "1":{"realDiscount":0,"id":7,"createdAt":"2014-08-22","description":"test 22","type":3,"totalFlat":0,"discountFlat":0,"discountFlatType":"%","chargedHours":0,"chargedMinutes":0,"hourlyRate":0,"discountHourly":0,"discountHourlyType":"%","chargedQuantity":50,"unitPrice":1,"discountQuantity":0,"discountQuantityType":"%","total":50,"discount":0,"discountType":"%","position":1,"chargedTime":0}
    }
},
"marchandises":[]}

Why in my JSON string, services[1] is formatted differently than services[3] ? If I refer to my PHP array, the only difference is that the first key of services[1] is 0, while the first key of services[3] is 1. It's like JMS Serializer is not mapping the key when it's equal to 0. In the end, i'd like to keep key equals to 0 in the JSON string.

How can I do that ?

Answer 1

To apply this logic to your whole project:

Just add those lines to your serializer config (config.yml):

jms_serializer:    
    visitors:
        json:
            options: [JSON_FORCE_OBJECT]

Source: http://jmsyst.com/bundles/JMSSerializerBundle/master/configuration#extension-reference

---

To apply this logic per call:

You'll have to create an EventSubscriber

<?php

namespace Acme\Api\Serializer;

use JMS\Serializer\EventDispatcher\Events;
use JMS\Serializer\EventDispatcher\EventSubscriberInterface;
use JMS\Serializer\EventDispatcher\PreSerializeEvent;
use JMS\Serializer\EventDispatcher\ObjectEvent;
use JMS\Serializer\JsonSerializationVisitor;

class JsonSerializationSubscriber implements EventSubscriberInterface
{
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents()
    {
        return array(
            array('event' => Events::PRE_SERIALIZE, 'method' => 'onPreSerialization', 'format' => 'json'),
            array('event' => Events::POST_SERIALIZE, 'method' => 'onPostSerialization', 'format' => 'json')
        );
    }

    /**
     * @param PreSerializeEvent $event
     */
    public function onPreSerialization(PreSerializeEvent $event)
    {
        $context = $event->getContext();

        if (!$context->attributes->contains('json_encode_options')) {
            return;
        }

        $visitor = $event->getVisitor();

        if ($visitor instanceof JsonSerializationVisitor) {
            $options = $visitor->getOptions();
            $context->setAttribute('__old_json_encode_options', $options);
            $visitor->setOptions($options | $context->attributes->get('json_encode_options'));
        }
    }

    /**
     * @param ObjectEvent $event
     */
    public function onPostSerialization(ObjectEvent $event)
    {
        $context = $event->getContext();

        if (!$context->attributes->contains('__old_json_encode_options')) {
            return;
        }

        $visitor = $event->getVisitor();

        if ($visitor instanceof JsonSerializationVisitor) {
            $visitor->setOptions($context->attributes->get('__old_json_encode_options'));
        }
    }
}

Register the EventSubscriber in your config file:

services:
    acme.serializer.subscriber.json:
        class: Acme\Api\Serializer\JsonSerializationSubscriber

        tags:
            - {name: jms_serializer.event_subscriber}

Then whenever you want to use it:

$context = new SerializationContext();
$context->setAttribute('json_encode_options', JSON_FORCE_OBJECT);

$this->get('serializer')->serialize($var, 'json', $context);