TypeError: Python object is not JSON serializable

Question

I am trying to encode an object into json using json.dumps() in Django, however when I pass in a python object, it raises this error.

TypeError         


        

Answer 1

The __dict__ gives all the attributes of the instance, but you don't want all that extra baggage - for the purposes of serialization, you are only interested in the fields.

Your model does not contain anything special so the built-in helper function model_to_dict should be enough for your needs:

import json
from django.forms.models import model_to_dict

oi = OrgInvite.objects.get(token=100) 
oi_dict = model_to_dict(oi)
oi_serialized = json.dumps(oi_dict)

Your example was simple, only containing CharField, BooleanField, and ForeignKey all of which we can dump to json trivially.

For more complicated models, you might consider writing your own serializer. In this case, I recommend using the popular django-rest-framework which does all the work for you.

from rest_framework import serializers

class OrgInviteSerializer(serializers.ModelSerializer):
    class Meta:
        model = OrgInvite
        fields = '__all__'

Answer 2

If you do invite.__dict__, it's going to give you a dictionary of all data related to one invite object. However, the dict's values are not necessarily primitive types, but objects as well(ModelState is just one of them). Serializing that would not only not working because json doesn't accept python objects, but you could also serialize a lot of meta data that's not used.

Check out json official website to see what data types are json serializable. The fix would be either using django model serializer, or manually create a dict that in compliance to json format.

Answer 3

object is not one of those types. Dictionaries, lists (maybe tuples), floats, strings, integers, bools, and None I believe are the types that Python can serialize into JSON natively.

However, it looks like Django has some built-in serializers that may work for you.

I'm guessing that

from django.core import serializers
data = serializers.serialize("json", OrgInvite.objects.filter(token=100))

should work for you