如何正确地为 Django 的用户模型添加权限？

Question

我正在尝试将自定义权限添加到 User 模型 (django.contrib.auth.models)。

我添加到我的users 应用程序的__init__.py 文件：

from django.db.models.signals import pre_migrate
from django.contrib.contenttypes.models import ContentType
from django.contrib.auth import models as auth_models
from django.contrib.auth.models import Permission
from django.conf import settings
from django.dispatch import receiver


@receiver(pre_migrate, sender=auth_models)
def add_user_permissions(sender, **kwargs):
    content_type = ContentType.objects.get_for_model(settings.AUTH_USER_MODEL)
    Permission.objects.get_or_create(codename='view_user', name=' Can view users', content_type=content_type)
    Permission.objects.get_or_create(codename='change_user_password', name=' Can change user password', content_type=content_type)

settings.py：

INSTALLED_APPS = [
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'django.forms',
    'django_select2',  # "django-select2" application
    'custom_app',  # "custom_app" application
    'custom_app_2',  # "custom_app_2" application
    'modeltranslation',  # "django-modeltranslation" application
    'users', # "users" application
]

错误：

Traceback (most recent call last):
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/utils/autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 117, in inner_run
    autoreload.raise_last_exception()
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/utils/autoreload.py", line 251, in raise_last_exception
    six.reraise(*_exception)
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/utils/autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/apps/registry.py", line 85, in populate
    app_config = AppConfig.create(entry)
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/apps/config.py", line 94, in create
    module = import_module(entry)
  File "/usr/local/Cellar/python/2.7.14/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/Applications/Projects/web/dashboard.kase.kz/users/__init__.py", line 5, in <module>
    from django.contrib.contenttypes.models import ContentType
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/contrib/contenttypes/models.py", line 139, in <module>
    class ContentType(models.Model):
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/db/models/base.py", line 110, in __new__
    app_config = apps.get_containing_app_config(module)
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/apps/registry.py", line 247, in get_containing_app_config
    self.check_apps_ready()
  File "/Users/nurzhan_nogerbek/Virtualenvs/py2714/lib/python2.7/site-packages/django/apps/registry.py", line 125, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

问题：如何解决此错误？

Answer 1

我终于从documentation找到了解决方案。

1) 您需要使用下一条命令创建空迁移：

python manage.py makemigrations --empty users

用户 - 应用名称

2) 命令创建0001_initial.py 文件，您需要在其中放置下一个代码：

# -*- coding: utf-8 -*-

from __future__ import unicode_literals
from django.db import migrations

def forwards_func(apps, schema_editor):
    User = apps.get_model('auth', 'User')
    Permission = apps.get_model('auth', 'Permission')
    ContentType = apps.get_model('contenttypes', 'ContentType')
    content_type = ContentType.objects.get_for_model(User)
    db_alias = schema_editor.connection.alias
    Permission.objects.using(db_alias).bulk_create([
        Permission(codename='view_user', name=' Can view users', content_type=content_type),
        Permission(codename='change_user_password', name=' Can change user password', content_type=content_type)
    ])


class Migration(migrations.Migration):

    dependencies = [
    ]

    operations = [
        migrations.RunPython(forwards_func),
    ]

Answer 2

请尝试在 init.py 文件的顶部添加此代码：

import django
django.setup()

Answer 3

将 init.py 中的所有代码复制到新创建的名为 signals.py 的文件中，并将 __init__.py 更改为：

default_app_config = 'user.apps.UserConfig'

信号.py

from django.db.models.signals import pre_migrate
from django.contrib.contenttypes.models import ContentType
from django.contrib.auth.models import AuthConfig
from django.contrib.auth.models import Permission
from django.conf import settings
from django.dispatch import receiver


@receiver(pre_migrate, sender=AuthConfig)
def add_user_permissions(sender, **kwargs):
    content_type = ContentType.objects.get_for_model(settings.AUTH_USER_MODEL)
    Permission.objects.get_or_create(codename='view_user', name=' Can view users', content_type=content_type)
    Permission.objects.get_or_create(codename='change_user_password', name=' Can change user password', content_type=content_type)

然后在 user/apps.py 中：

from django.apps import AppConfig


class UserConfig(AppConfig):
    name = 'user'
    verbose_name = 'User'

    def ready(self):
        import user.signals

你的错误是occer，因为__init__.py会在models.py中调用User，但是在__init__.py运行结束后会注册用户模型，所以你需要在你的用户模型准备好时调用你的信号。

---

您想添加一些与用户相关的权限：

class MyUser(User):

    class Meta:
        permissions = (
            ("view_user", "view_user"),
            ("change_user_password", "change_user_password"),
        )

在settings.py中

AUTH_USER_MODEL = "user.MyUser"