is not JSON serializable

问题

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 ?

回答1:

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.

回答2:

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)})

回答3:

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

回答4:

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) )

回答5:

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

回答6:

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))

来源：https://stackoverflow.com/questions/16790375/django-object-is-not-json-serializable

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python