[Django]-<Django object > is not JSON serializable

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168đź‘Ť

âś…

simplejson and json don’t work with django objects well.

Django’s built-in serializers can only serialize querysets filled with django objects:

data = serializers.serialize('json', self.get_queryset())
return HttpResponse(data, content_type="application/json")

In your case, self.get_queryset() contains a mix of django objects and dicts inside.

One option is to get rid of model instances in the self.get_queryset() and replace them with dicts using model_to_dict:

from django.forms.models import model_to_dict

data = self.get_queryset()

for item in data:
   item['product'] = model_to_dict(item['product'])

return HttpResponse(json.simplejson.dumps(data), mimetype="application/json")
👤alecxe

122đź‘Ť

The easiest way is to use a JsonResponse.

For a queryset, you should pass a list of the the values for that queryset, like so:

from django.http import JsonResponse

queryset = YourModel.objects.filter(some__filter="some value").values()
return JsonResponse({"models_to_return": list(queryset)})
👤YPCrumble

28đź‘Ť

I found that this can be done rather simple using the “.values” method, which also gives named fields:

result_list = list(my_queryset.values('first_named_field', 'second_named_field'))
return HttpResponse(json.dumps(result_list))

“list” must be used to get data as iterable, since the “value queryset” type is only a dict if picked up as an iterable.

Documentation: https://docs.djangoproject.com/en/1.7/ref/models/querysets/#values

👤Danny Staple

26đź‘Ť

From version 1.9
Easier and official way of getting json

from django.http import JsonResponse
from django.forms.models import model_to_dict


return JsonResponse(  model_to_dict(modelinstance) )
👤Yash

14đź‘Ť

Another great way of solving it while using a model is by using the values() function.

def returnResponse(date):
    response = ScheduledDate.objects.filter(date__startswith=date).values()
    return Response(response)
👤Dr4kk0nnys

13đź‘Ť

Our js-programmer asked me to return the exact JSON format data instead of a json-encoded string to her.

Below is the solution.(This will return an object that can be used/viewed straightly in the browser)

import json
from xxx.models import alert
from django.core import serializers

def test(request):
    alert_list = alert.objects.all()

    tmpJson = serializers.serialize("json",alert_list)
    tmpObj = json.loads(tmpJson)

    return HttpResponse(json.dumps(tmpObj))
👤HiRob

9đź‘Ť

First I added a to_dict method to my model ;

def to_dict(self):
    return {"name": self.woo, "title": self.foo}

Then I have this;

class DjangoJSONEncoder(JSONEncoder):

    def default(self, obj):
        if isinstance(obj, models.Model):
            return obj.to_dict()
        return JSONEncoder.default(self, obj)


dumps = curry(dumps, cls=DjangoJSONEncoder)

and at last use this class to serialize my queryset.

def render_to_response(self, context, **response_kwargs):
    return HttpResponse(dumps(self.get_queryset()))

This works quite well

👤tuna

1đź‘Ť

For Django Model, try:

users = User.objects.all()   
return JsonResponse ({'data' : list(users)})
👤Adrian John

0đź‘Ť

You can use this for the Django model. Here we get rid of the wrapper because of safe=False, without it there will be an error. But .values() will return you the key->value in a multidimensional array

views.py

from django.http import JsonResponse

users = User.objects.all().values()
return JsonResponse(list(users), safe=False)
👤Igor Vasiliev

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