is not JSON serializable

Question

I have the following code for serializing the queryset;

def render_to_response(self, context, **response_kwargs):

    return HttpResponse(json.simplejson.dumps(list(self.get_queryset())),
                        mimetype="application/json")

And following is my get_querset()

[{'product': <Product: hederello ()>, u'_id': u'9802', u'_source': {u'code': u'23981', u'facilities': [{u'facility': {u'name': {u'fr': u'G\xe9n\xe9ral', u'en': u'General'}, u'value': {u'fr': [u'bar', u'r\xe9ception ouverte 24h/24', u'chambres non-fumeurs', u'chambres familiales',.........]}]

Which I need to serialize. But it says not able to serialize the <Product: hederello ()>. Because list composed of both django objects and dicts. Any ideas ?

Does this answer your question? [Convert Django Model object to dict with all of the fields intact](https://stackoverflow.com/questions/21925671/convert-django-model-object-to-dict-with-all-of-the-fields-intact) — Matej J, Oct 09 '20 at 22:35

score 147 · Accepted Answer · edited Jun 21 '17 at 11:51

147

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")

Hope that helps.

edited Jun 21 '17 at 11:51

cyph3rn3tz

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answered May 28 '13 at 11:04

alecxe

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Now getting error --> `'NoneType' object has no attribute 'concrete_model'` ... And using Django 1.4+ – tuna May 28 '13 at 11:42
3

When the model has a datetime field, it does not work. – ax003d Mar 12 '14 at 08:18
that solution will trigger a lot of queries – Julio Marins Mar 18 '19 at 19:12
to use that directly in JS, just use the `safe` tage. https://stackoverflow.com/a/57939897/4157431 – Rami Alloush Sep 14 '19 at 23:01
is there also a way back? besides, you will override the product in your solution if it happens that there are more items in data – Macilias Feb 26 '22 at 21:36

score 105 · Answer 2 · answered Dec 13 '16 at 20:07

105

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)})

answered Dec 13 '16 at 20:07

YPCrumble

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8

thanks for .values(), In my case, I just need to add .values() after filter – lwin Jul 29 '19 at 01:51

score 27 · Answer 3 · answered Oct 07 '14 at 16:32

27

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

answered Oct 07 '14 at 16:32

Danny Staple

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This worked well for me. Even though the error message suggests it's all in one big list, the `list()` is still apparently needed. – trpt4him May 18 '15 at 10:46

score 19 · Answer 4 · answered Oct 13 '16 at 17:59

19

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) )

answered Oct 13 '16 at 17:59

Yash

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Woody Johnson · Answer 5 · 2019-07-08T09:31:12.670

12

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))

edited Jul 08 '19 at 09:31

answered Sep 27 '18 at 07:31

Woody Johnson

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Will be better just `HttpResponse(tmpObj)` – Pablo Díaz Jul 17 '20 at 05:48

score 9 · Answer 6 · answered May 28 '13 at 12:20

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

score 8 · Answer 7 · answered Nov 06 '20 at 18:44

8

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)

answered Nov 06 '20 at 18:44

Dr4kk0nnys

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is not JSON serializable

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