Question

Django has a built in serialization functionality which allows you to serialize any query result set into JSON:

json_serializer = serializers.get_serializer("json")()
json_serializer.serialize(queryset, ensure_ascii=False)

This produces output such as:

[
  {
    "pk": 1, 
    "model": "app_name.model_name", 
    "fields": {
      "field_name": "value", 
      (...)
    }
  }
]

If you want to pass this JSON object over to an ExtJS driven application you run into a problem, because ExtJS expects its JSON to be formatted differently:

{
    "total": 100,
    "success": true,
    "objects": [
        {
            "id": 1,
            "field_name": "value",
            (...)
        }
    ]
}

There are 2 main differences: the additional meta-data (success, total) and the IDs of the objects which are provided together with other fields in Ext, but not in Django.

There are many possible ways to make one or the other format conform with the second, but what do you consider to be the best way to make this work? Is it a special serializer on the Django side, or maybe a special reader on the ExtJS side…

What do you think is the best way to solve this problem?

Answer 1

I found a solution which is able to serialize objects, which contain QuerySet as attributes. It’s comes from traddicts.org blog, but you can now find it on GitHub:

https://github.com/datamafia/django-query-json-serializer/blob/master/JSONSerializer.py

I further modified the code to work recursively, so in effect I can do the following:

users = User.objects.all()
response = {}
response['success'] = True
response['users'] = users
json_serialize(response)
json_serialize(response, serialize_related=True)
json_serialize(response, serialize_related=True, ignored=['users.groups'])
json_serialize(response, serialize_related=True, ignored=['users.groups.permissions'])

I like your answer Thomas, but I needed something which would be even more flexible.