Django & Djson… er, JSON

I must admin this is my first attempt at even using JSON. I wanted to produce some data that I could consume with jQuery and I figured JSON was the best format for the job.

I found Django has a method for serializing Model query sets easily and it seemed to work just fine.

The problem I was having was that I needed information from two different models. I have Envelopes that Belong to EnvelopeCategories. I wanted to return each category with all the envelopes that belonged in that category.

I kept running into errors when I would try to serialize with Django's serializer function. Basically, if I created a dictionary with what I needed, it was serialized. If I used a query set it wouldn't add the parent fields, or any additional fields I wanted to add. But finally, after browsing around the net and piecing things together I cam up with a solution:

from django.utils import simplejson
from django.http import HttpResponse
from mysite.myapp.models import EnvelopeCategory, Envelope

def json_envelopes(request):
    categories = EnvelopeCategory.objects.filter(user=request.user)
    # Create dict with information to create JSON feed
    catenvs = []
    for cat in categories:
        cat.envelopes = Envelope.objects.filter(category=cat)
        envs = []
        for env in cat.envelopes:
            envs.append({'id': env.id, 'name': env.title, 'order': env.order})
        catenvs.append({'id': cat.id, 'name': cat.title, 'envelopes': envs, 'order': cat.order})
    # Use simplejson to serialize dict
    data = simplejson.dumps(catenvs, indent=4)
    return HttpResponse(data, mimetype='application/javascript')

Now, on to figuring out how to consume it for me needs. 😁