如何取消缓存Django模型

我有一个叫 Chat 可以从自身存储和检索Cookie,如下所示:

>>> chat = Chat.objects.get(pk=43265)
>>> chat.cookies
>>> chat.set_cookie('1','2')
>>> chat.cookies
'{"1": "2"}'

这个 set_cookies 方法是用一个简单的 json.dumps :

def set_cookie(self, key, value):
    if self.cookies:
        current_cookies = json.loads(self.cookies)
    else:
        current_cookies = dict()
    current_cookies.update({key: value})
    self.cookies = json.dumps(current_cookies)
    self.save()

问题是,如果 chat 对象在两个不同的名称空间中检索,它们独立更新其Cookie,每一个都覆盖另一个的结果。

例子:

import django
django.setup()

from bots.models import Chat

# Let's clean all the cookies beforehand 
c = Chat.objects.get(pk=43265)
c.cookies = None
c.save()

def outer_namespace():
    chat = Chat.objects.get(pk=43265)

    # here chat.cookies are empty
    inner_namespace()
    # Now we are supposed to have inner cookie here - right? Let's set another one.

    chat.set_cookie('outer namespace cookie', '1')

    # Let's retrieve the model again and see
    print(Chat.objects.get(pk=43265).cookies)


def inner_namespace():
    inner_chat = Chat.objects.get(pk=43265)
    inner_chat.set_cookie('inner namespace cookie', '2')


outer_namespace()

如果我运行这个,我会得到:

>>> {"outer namespace cookie": "1"}
>>> # we lost one of the cookies!

如何避免这种情况? 我提出的唯一解决方案是重新检索 闲聊 对象位于其自身的中间 set_cookies 方法但这看起来很笨拙。

def set_cookie(self, key, value):
    cookies = self.__class__.objects.get(pk=self.pk).cookies
    #
    # ... rest of the method stays the same