创建 django 权限，错误：ContentType 匹配查询不存在

Question

我正在尝试添加两个组并授予他们访问我的 Django 项目的权限。但我不断收到错误消息：

ContentType 匹配查询不存在。

我正在运行：Django 1.5.4 Python 2.7.3 South 0.8.2 PostreSQL 9.3

这是我的代码：

import django
from django.contrib.auth.models import Group, Permission
from django.contrib.contenttypes.models import ContentType 

from .models import Flavor

def add_groups():
    # Create User Groups
    special_users = Group(name='Special Users')
    special_users.save()
    really_special_users = Group(name='Super Special Users')
    really_special_users.save()

def add_permissions():
    # Define a View permission for the 1st group, and a View/Modify permission for the 2nd group
    somemodel_ct = ContentType.objects.get(app_label='flavors', model='flavors_flavor')
    can_view = Permission(name='Can View', codename='can_view_something', content_type=somemodel_ct)
    can_view.save()
    can_modify = Permission(name='Can Modify', codename='can_modify_something', content_type=somemodel_ct)
    can_modify.save()

def give_perm_to_groups():
    # Associate these two permissions now with a Group
    special_users.permissions.add(can_view)
    really_special_users.permissions = [can_view, can_modify]

我可以正常运行 add_groups()。现在正在工作的是 add_permissions()。我相信这与 Postgres 中的装置有关，但不确定如何添加它们，或者这是否是确切的问题？

谢谢

这是整个错误回溯：

>>> add_permissions()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Users/Yuki_Aaron/Documents/djcode/demoproject/flavors/groups.py", line 16, in add_permissions
    somemodel_ct = ContentType.objects.get(app_label='flavors', model='flavors_flavor')
  File "/Users/Yuki_Aaron/Documents/virtualenvs/django1.5/lib/python2.7/site-packages/django/db/models/manager.py", line 143, in get
    return self.get_query_set().get(*args, **kwargs)
  File "/Users/Yuki_Aaron/Documents/virtualenvs/django1.5/lib/python2.7/site-packages/django/db/models/query.py", line 404, in get
    self.model._meta.object_name)
DoesNotExist: ContentType matching query does not exist.

Answer 1

我要做的第一件事是将其更改somemodel_ct为：

somemodel_ct = ContentType.objects.get(app_label='flavors', model='flavor')

第二件事是，错误是由于以下事实造成的：我需要向模型添加权限，以便django.contrib.auth.models......Permission并且Group能够查找模型中定义的权限，然后关联回这ContentType。models.py这是我添加到我的代码中以使其正常工作的代码：

class Flavor(models.Model):
...
    class Meta:
            permissions = (
                ('can_view', 'Can View'),
                ('can_modify', 'Can Modify'),
            )

这样，我的Flavor模型就可以查找Permission表中的权限。这就是为什么它这么说，ContentType: no matching query因为我没有将其包含class Meta: permissions在我的实际Flavor模型中。

感谢您的帮助！