JsonResponse can't handle model_to_dict() with empty ImageField

[Komarov Valentin]

I have a model:

class Item(models.Model):

    title = models.TextField(verbose_name='Default title')
    photo = models.ImageField(
        verbose_name='Photo',
        upload_to='media/',
        blank=True,
    )

    def __str__(self):
        return self.title

I am trying to serialize this model object, to answer as json to frontend.

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


def get(self, request, *args, **kwargs):
    item_object = Item.objects.first()
    to_json = model_to_dict(item_object)
    return JsonResponse(to_json)

If my item.photo is empty (I haven't download photo yet), JsonResponse throw TypeError: <ImageFieldFile: None> is not JSON serializable

[16/Nov/2016 13:51:15] "GET /items/?item_id=9&shop_id=4 HTTP/1.1" 500 129160
Internal Server Error: /items/
Traceback (most recent call last):
  File "/home/lamberk/python/picasel/rc_cross_upsell/venv/lib/python3.5/site-packages/django/core/handlers/exception.py", line 39, in inner
    response = get_response(request)
  File "/home/lamberk/python/picasel/rc_cross_upsell/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/home/lamberk/python/picasel/rc_cross_upsell/venv/lib/python3.5/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/home/lamberk/python/picasel/rc_cross_upsell/venv/lib/python3.5/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/home/lamberk/python/picasel/rc_cross_upsell/venv/lib/python3.5/site-packages/django/views/generic/base.py", line 88, in dispatch
    return handler(request, *args, **kwargs)
  File "/home/lamberk/python/picasel/rc_cross_upsell/CrossUpsell/apps/items/views.py", line 54, in get
    'up_sells': up_sells,
  File "/home/lamberk/python/picasel/rc_cross_upsell/venv/lib/python3.5/site-packages/django/http/response.py", line 520, in __init__
    data = json.dumps(data, cls=encoder, **json_dumps_params)
  File "/usr/lib/python3.5/json/__init__.py", line 237, in dumps
    **kw).encode(obj)
  File "/usr/lib/python3.5/json/encoder.py", line 198, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.5/json/encoder.py", line 256, in iterencode
    return _iterencode(o, 0)
  File "/home/lamberk/python/picasel/rc_cross_upsell/venv/lib/python3.5/site-packages/django/core/serializers/json.py", line 118, in default
    return super(DjangoJSONEncoder, self).default(o)
  File "/usr/lib/python3.5/json/encoder.py", line 179, in default
    raise TypeError(repr(o) + " is not JSON serializable")

Is it a bug or i can't understand something?

[Tim Graham]

The docstring for model_to_dict() says, "Returns a dict containing the data in instance suitable for passing as a Form's initial keyword argument." As far as I see, it's not meant for serializing a model for JsonResponse.

[Komarov Valentin]

Where is a right way to serialize empty ImageField?

[Tim Graham]

Please use our support channels for usage questions. Thanks.