TypeError:Python对象不是JSON可序列化的

Question

我正在尝试使用json.dumps()Django 将对象编码为json ,但是当我传入python对象时,它会引发此错误.

TypeError: <OrgInvite: OrgInvite object> is not JSON serializable

我假设即使JSON只能编码某些数据类型,其中一种数据类型就是对象.我在Stack Overflow上读到了另一个问题,解决这个问题的一个好方法是使用.__dict__我试过的方法从对象中创建一个字典,它说我的新字典中的一个键,_state是不可序列化的.我不确定这个_state键是从哪里来的,并且想知道有没有办法将我的对象转换为没有那个额外字段的字典,所以我可以将它编码为JSON？

模型:

class OrgInvite(models.Model):
    token = models.CharField(max_length=16, unique=True, null=False)
    account_id = models.ForeignKey(Account, on_delete=models.CASCADE, null=False)
    org_id = models.ForeignKey(Org, on_delete=models.CASCADE, null=False)
    used = models.BooleanField(default=False)
    is_admin = models.BooleanField(default=False)
    name = models.CharField(max_length=70)
    email = models.CharField(max_length=255)

视图:

def get_invite(token):
    if not token:
        raise Exception("Invitation token is not specified")

    invitation = OrgInvite.objects.get(token=token)
    if not invitation:
        raise Exception("Invitation token is invalid.")

    return invitation

def invite_accept_redirect(token):
    # """ -Redirects to the accept invite frontend view with pre-fetched data. """

    try:
        invite = get_invite(token)
        if not invite:
            raise Exception("Invitation token is invalid")
        if invite.used:
            invite = {'used': True}
    except:
        invite = {'invalid': True}
        raise Exception("Resource not found.")

    base = "home/accept"

    url = '{}/{}?data={}'.format(base, token, urllib.quote_plus(json.dumps(invite.__dict__)))

    return redirect(url)

安慰:

>>> oi = OrgInvite.objects.get(token=100) 
>>> oi
<OrgInvite: OrgInvite object>
>>> oix = oi.__dict__
>>> oix
{'used': False, 'name': u'', '_state': <django.db.models.base.ModelState object at 0x10377a610>, 'email': u'', 'token': u'100', 'org_id_id': 101, 'account_id_id': 301, 'is_admin': False, 'id': 1}
>>> json.dumps(oix)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/__init__.py", line 244, in dumps
    return _default_encoder.encode(obj)
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 207, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 270, in iterencode
    return _iterencode(o, 0)
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/json/encoder.py", line 184, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: <django.db.models.base.ModelState object at 0x10377a610> is not JSON serializable

Answer 1

在__dict__给出了实例的所有属性,但你不希望所有的微胖-序列化的目的,你只是在田里感兴趣.

您的模型不包含任何特殊内容,因此内置帮助程序功能model_to_dict应该足以满足您的需求:

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)

你的例子很简单,只包含CharField,BooleanField以及ForeignKey我们可以轻松转储的所有内容json.

对于更复杂的模型,您可以考虑编写自己的序列化程序.在这种情况下,我建议使用流行的django-rest-framework,它可以为您完成所有工作.

from rest_framework import serializers

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