============================================================== 使用Django认证系统(Using the Django authentication system) ============================================================== .. currentmodule:: django.contrib.auth 这篇文档解释默认配置下Django认证系统的使用方法. 这些配置可以满足大部分常见项目的需要, 可以处理各类任务, 同时有一套细致的密码和权限实现. 对于需要不同于默认认证的需求, Django认证支持大量的 :doc:`扩展和定制 ` . Django认证 提供用户认证和授权, 并统一称为认证系统, 因为它们之间有一些特性是耦合的. .. _user-objects: ``User`` 对象 ================ :class:`~django.contrib.auth.models.User` 对象是认证系统的核心. 它们通常代表人们与您网站的互动, 同时用于支持诸如访问限制, 注册用户, 将内容与创建者关联在一起等等. 在Django认证框架中只存在一种类型的用户, 换句话说, :attr:`'superusers' ` 或管理员 :attr:`'staff' ` 用户只是具有特殊属性集的user对象, 而不是不同于user对象的其他类. 默认用户的主要属性是: * :attr:`~django.contrib.auth.models.User.username` * :attr:`~django.contrib.auth.models.User.password` * :attr:`~django.contrib.auth.models.User.email` * :attr:`~django.contrib.auth.models.User.first_name` * :attr:`~django.contrib.auth.models.User.last_name` 通过 :class:`full API documentation ` 查看所有参考, 接下来的文档侧重于特定的任务. .. _topics-auth-creating-users: 创建用户 -------------- 创建用户最直接的方法就是使用 :meth:`~django.contrib.auth.models.UserManager.create_user` 函数:: >>> from django.contrib.auth.models import User >>> user = User.objects.create_user('john', 'lennon@thebeatles.com', 'johnpassword') # At this point, user is a User object that has already been saved # to the database. You can continue to change its attributes # if you want to change other fields. >>> user.last_name = 'Lennon' >>> user.save() 如果你安装了 Django admin, 你还可以 :ref:`交互式创建用户 `. .. _topics-auth-creating-superusers: 创建超级用户 ------------------- 创建超级用户使用命令 :djadmin:`createsuperuser` :: $ python manage.py createsuperuser --username=joe --email=joe@example.com 将会提示您输入密码. 在您输入并回车之后, 用户会立即被创建. 如果你不使用 :option:`--username ` 参数或 :option:`--email ` 参数, 它会提示您输入这些信息. 修改密码 ------------------ 在user模型, Django不存储明文密码, 仅存储对应哈希值 (所有细节请查看 :doc:`密码是如何管理的 ` ). 因此, 不要尝试直接修改user的password属性. 这就是使用辅助函数创建用户的原因. 你有以下几种方式修改用户密码: :djadmin:`manage.py changepassword *username* ` 提供命令行修改用户密码的方法. 它会提示您, 修改指定用户的密码, 两次输入的密码一致, 更改会立即生效. 如果你没有指定用户, 命令行将尝试修改与当前系统用户匹配的用户名的密码. 你也可以使用编程的方式, 通过 :meth:`~django.contrib.auth.models.User.set_password()` 来修改密码: .. code-block:: pycon >>> from django.contrib.auth.models import User >>> u = User.objects.get(username='john') >>> u.set_password('new password') >>> u.save() 如果你安装了 Django admin, :ref:`认证系统的管理员页面 ` 修改用户密码. Django同时提供了 :ref:`views ` 和 :ref:`forms ` 允许用户修改他们自己的密码. 修改用户密码, 会注销所有该用户的会话(sessions). 详情请查看 :ref:`session-invalidation-on-password-change` . 验证用户 -------------------- .. function:: authenticate(request=None, \**credentials) 使用 :func:`~django.contrib.auth.authenticate()` 来验证用户的凭证. 默认情况接受 ``username`` 和 ``password`` 作为关键字参数, 在每个需要认证的后端检查它们 :ref:`authentication backend `, 如果后端验证凭证有效, 返回一个 :class:`~django.contrib.auth.models.User` 对象. 如果凭证无效或者后端触发一个 :class:`~django.core.exceptions.PermissionDenied` 异常, 则返回 ``None``. 示例:: from django.contrib.auth import authenticate user = authenticate(username='john', password='secret') if user is not None: # A backend authenticated the credentials else: # No backend authenticated the credentials ``request`` 是一个可选的 :class:`~django.http.HttpRequest` 参数, 它被认证后端传递给 ``authenticate()`` 方法. .. note:: 这是认证凭据的初级方法; 例如, 它被 :class:`~django.contrib.auth.middleware.RemoteUserMiddleware` 使用. 除非你正在编写你自己的认证系统, 否则你可能不会用到它. 当然, 如果你在找一种登录用户的方法, 请使用 :class:`~django.contrib.auth.views.LoginView`. .. _topic-authorization: 权限和授权 ============================= Django提供了一个简单的权限系统. 他提供一种方法将权限分配给特定用户和用户组. 它被用于Django admin, 但欢迎你在代码中使用它. Django admin 使用权限如下: * 拥有该类对象 "add" 权限的用户才可以访问 "add" 表单以及添加一个该类对象类型. * 拥有该类对象 "change" 权限的用户才可以查看修改列表, 访问 "change" 表单以及修改一个该类对象. * 拥有该类对象 "delete" 权限的用户才可以删除一个该类对象. 权限不仅可以设置为每个对象的类型, 而且可以设置为每个特定对象. 通过使用 :class:`~django.contrib.admin.ModelAdmin` 类提供的 :meth:`~django.contrib.admin.ModelAdmin.has_add_permission`, :meth:`~django.contrib.admin.ModelAdmin.has_change_permission` 和 :meth:`~django.contrib.admin.ModelAdmin.has_delete_permission` 方法, 可以针对相同类型的不同实例自定义权限. :class:`~django.contrib.auth.models.User` 对象有两个多对多的字段: ``groups`` 和 ``user_permissions``. :class:`~django.contrib.auth.models.User` 对象可以用和其他 :doc:`Django 模型 ` 一样的方法去访问它们相关的对象:: myuser.groups.set([group_list]) myuser.groups.add(group, group, ...) myuser.groups.remove(group, group, ...) myuser.groups.clear() myuser.user_permissions.set([permission_list]) myuser.user_permissions.add(permission, permission, ...) myuser.user_permissions.remove(permission, permission, ...) myuser.user_permissions.clear() 默认权限 ------------------- 当 ``django.contrib.auth`` 在你的 :setting:`INSTALLED_APPS` 设置中列出时, 它将确保为你安装的应用中定义的每个Django模型创建3个默认的权限 -- add, change 和 delete. 这些权限将在你执行 :djadmin:`manage.py migrate ` 命令的时候创建; 在你添加 ``django.contrib.auth`` 到 :setting:`INSTALLED_APPS` 设置之后, 第一次运行 ``migrate`` 时, 将会为之前安装的模型, 以及此时正在安装的新模型创建默认的权限. 之后, 每次运行 :djadmin:`manage.py migrate ` (创建权限的这个函数会被连通到 :data:`~django.db.models.signals.post_migrate` 信号) 时, 都会为新创建的模型创建默认的权限. 假设你有一个 :attr:`~django.db.models.Options.app_label` 叫做 ``foo`` 的应用, 这个应用有一个 ``Bar`` 模型, 要测试基本权限, 你应该使用: * add: ``user.has_perm('foo.add_bar')`` * change: ``user.has_perm('foo.change_bar')`` * delete: ``user.has_perm('foo.delete_bar')`` 很少直接访问 :class:`~django.contrib.auth.models.Permission` 模型. 组 ------ :class:`django.contrib.auth.models.Group` 模型是用户分类的一种常用方式, 通过这种方式你可以应用权限或其他标签到这一类用户. 用户可以属于任意数量的组. 组中的用户自动具有赋给该组的权限. 例如, 如果组 ``Site editors`` 具有 ``can_edit_home_page`` 权限, 所有该组的用户都具有该权限. 除权限意外, 组方便给一类用户设置某个标签或扩展的功能. 比如, 你可以创建一个组 ``'Special users'``, 然后你可以这样编写代码, 给他们访问你站点会员部分的内容, 或者给他们发送仅限于会员的邮件. 通过编程的方式创建权限 ------------------------------------- :ref:`自定义权限 ` 可以定义在模型的 ``Meta`` 类中, 也可以直接创建权限. 例如, 你可以在 ``myapp`` 中为 ``BlogPost`` 模型创建 ``can_publish`` 权限:: from myapp.models import BlogPost from django.contrib.auth.models import Permission from django.contrib.contenttypes.models import ContentType content_type = ContentType.objects.get_for_model(BlogPost) permission = Permission.objects.create( codename='can_publish', name='Can Publish Posts', content_type=content_type, ) 然后该权限可以通过 ``user_permissions`` 属性分配给一个 :class:`~django.contrib.auth.models.User` 或者通过 ``permissions`` 属性分配给 :class:`~django.contrib.auth.models.Group` 权限缓存 ------------------ :class:`~django.contrib.auth.backends.ModelBackend` 在第一次需要访问 ``User`` 对象时, 会 缓存它们的权限. 这对于请求-响应循环还是比较好的, 因为在权限添加进来后并不会立即检查(例如在 admin中). 如果你正在添加权限并且需要立即检查它们, 例如在一个测试或view中, 最简单的解决办法是从数据库中重新获取 ``User`` 例如:: from django.contrib.auth.models import Permission, User from django.contrib.contenttypes.models import ContentType from django.shortcuts import get_object_or_404 from myapp.models import BlogPost def user_gains_perms(request, user_id): user = get_object_or_404(User, pk=user_id) # any permission check will cache the current set of permissions user.has_perm('myapp.change_blogpost') content_type = ContentType.objects.get_for_model(BlogPost) permission = Permission.objects.get( codename='change_blogpost', content_type=content_type, ) user.user_permissions.add(permission) # Checking the cached permission set user.has_perm('myapp.change_blogpost') # False # Request new instance of User # Be aware that user.refresh_from_db() won't clear the cache. user = get_object_or_404(User, pk=user_id) # Permission cache is repopulated from the database user.has_perm('myapp.change_blogpost') # True ... .. _auth-web-requests: Web 请求中的认证 ============================== Django使用 :doc:`会话(sessions) ` 和中间件来拦截 :class:`request objects `. 他们在每个请求上提供一个 :attr:`request.user ` 属性, 代表当前用户. 如果当前用户没有登录, 该属性将设置成 :class:`~django.contrib.auth.models.AnonymousUser` 实例, 否则它会是一个 :class:`~django.contrib.auth.models.User` 实例. 你可以使用 :attr:`~django.contrib.auth.models.User.is_authenticated` 区分, 例如:: if request.user.is_authenticated: # Do something for authenticated users. ... else: # Do something for anonymous users. ... .. _how-to-log-a-user-in: 如何登录一个用户 -------------------- 如果你有一个认证了的用户, 你想把它附加到当前会话中, - 可以使用 :func:`~django.contrib.auth.login` 函数. .. function:: login(request, user, backend=None) 从视图登录一个用户, 使用 :func:`~django.contrib.auth.login()`. 它接受一个 :class:`~django.http.HttpRequest` 对象和一个 :class:`~django.contrib.auth.models.User` 对象. :func:`~django.contrib.auth.login()` 使用Django的session框架将用户ID保存在session中. 注意, 任何在匿名会话中设置的数据都会在用户登录后保存在会话中. 下面示例演示如何使用 :func:`~django.contrib.auth.authenticate()` 和 :func:`~django.contrib.auth.login()`:: from django.contrib.auth import authenticate, login def my_view(request): username = request.POST['username'] password = request.POST['password'] user = authenticate(request, username=username, password=password) if user is not None: login(request, user) # Redirect to a success page. ... else: # Return an 'invalid login' error message. ... 选择认证后端 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When a user logs in, the user's ID and the backend that was used for authentication are saved in the user's session. This allows the same :ref:`authentication backend ` to fetch the user's details on a future request. The authentication backend to save in the session is selected as follows: #. Use the value of the optional ``backend`` argument, if provided. #. Use the value of the ``user.backend`` attribute, if present. This allows pairing :func:`~django.contrib.auth.authenticate()` and :func:`~django.contrib.auth.login()`: :func:`~django.contrib.auth.authenticate()` sets the ``user.backend`` attribute on the user object it returns. #. Use the ``backend`` in :setting:`AUTHENTICATION_BACKENDS`, if there is only one. #. Otherwise, raise an exception. In cases 1 and 2, the value of the ``backend`` argument or the ``user.backend`` attribute should be a dotted import path string (like that found in :setting:`AUTHENTICATION_BACKENDS`), not the actual backend class. 如何登出一个用户 --------------------- .. function:: logout(request) 登出一个通过 :func:`django.contrib.auth.login()` 登录的用户, 可以在视图中使用 :func:`django.contrib.auth.logout()` . 它接收一个 :class:`~django.http.HttpRequest` 对象且没有返回值. 示例:: from django.contrib.auth import logout def logout_view(request): logout(request) # Redirect to a success page. 注意, 用户没有登录, 调用函数 :func:`~django.contrib.auth.logout()` 也不会抛出任何错误. 当你调用 :func:`~django.contrib.auth.logout()`, 当前请求的会话数据将会被清除. 所有存在的数据都会被清除. 这是为了防止其他用户使用相同的web浏览器登录并访问前一个用户的会话数据. 如果你想再用户登出之后, 可以立即访问放入会话中的数据, 请在调用 :func:`django.contrib.auth.logout()` 之后放入. 仅允许登录用户访问 ---------------------------------- 原始方法 ~~~~~~~~~~~ 限制页面访问的简单, 原始的方法就是检查 :attr:`request.user.is_authenticated ` 并重定向到登录页面:: from django.conf import settings from django.shortcuts import redirect def my_view(request): if not request.user.is_authenticated: return redirect('%s?next=%s' % (settings.LOGIN_URL, request.path)) # ... ...或者显示一个错误信息:: from django.shortcuts import render def my_view(request): if not request.user.is_authenticated: return render(request, 'myapp/login_error.html') # ... .. currentmodule:: django.contrib.auth.decorators ``login_required`` 装饰器 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. function:: login_required(redirect_field_name='next', login_url=None) 作为一个快捷方式, 你可以使用 :func:`~django.contrib.auth.decorators.login_required` 装饰器:: from django.contrib.auth.decorators import login_required @login_required def my_view(request): ... :func:`~django.contrib.auth.decorators.login_required` 完成以下事情: * 如果用户没有登录, 跳转到 :setting:`settings.LOGIN_URL `, 并将当前访问的绝对路径传递到查询字符串中. 例如: ``/accounts/login/?next=/polls/3/``. * 如果用户已经登录, 则正常执行视图. 编写视图代码时, 我们可以安全地假设用户已经登录. 默认情况下, 认证成功之后, 用户被重定向的路径存储在查询字符串的 ``"next"`` 参数中. 如果你想修改参数的名字, 可以使用 :func:`~django.contrib.auth.decorators.login_required` 的可选参数 ``redirect_field_name`` :: from django.contrib.auth.decorators import login_required @login_required(redirect_field_name='my_redirect_field') def my_view(request): ... 注意如果你传递了 ``redirect_field_name`` 参数, 你需要同时修改你的登录模板, 因为存储重定向路径的模板上下文变量将使用传递给参数 ``redirect_field_name`` 的值, 而不是默认的 ``"next"`` . :func:`~django.contrib.auth.decorators.login_required` also takes an optional ``login_url`` parameter. Example:: from django.contrib.auth.decorators import login_required @login_required(login_url='/accounts/login/') def my_view(request): ... Note that if you don't specify the ``login_url`` parameter, you'll need to ensure that the :setting:`settings.LOGIN_URL ` and your login view are properly associated. For example, using the defaults, add the following lines to your URLconf:: from django.contrib.auth import views as auth_views path('accounts/login/', auth_views.LoginView.as_view()), The :setting:`settings.LOGIN_URL ` also accepts view function names and :ref:`named URL patterns `. This allows you to freely remap your login view within your URLconf without having to update the setting. .. note:: The ``login_required`` decorator does NOT check the ``is_active`` flag on a user, but the default :setting:`AUTHENTICATION_BACKENDS` reject inactive users. .. seealso:: If you are writing custom views for Django's admin (or need the same authorization check that the built-in views use), you may find the :func:`django.contrib.admin.views.decorators.staff_member_required` decorator a useful alternative to ``login_required()``. .. currentmodule:: django.contrib.auth.mixins The ``LoginRequired`` mixin ~~~~~~~~~~~~~~~~~~~~~~~~~~~ When using :doc:`class-based views `, you can achieve the same behavior as with ``login_required`` by using the ``LoginRequiredMixin``. This mixin should be at the leftmost position in the inheritance list. .. class:: LoginRequiredMixin If a view is using this mixin, all requests by non-authenticated users will be redirected to the login page or shown an HTTP 403 Forbidden error, depending on the :attr:`~django.contrib.auth.mixins.AccessMixin.raise_exception` parameter. You can set any of the parameters of :class:`~django.contrib.auth.mixins.AccessMixin` to customize the handling of unauthorized users:: from django.contrib.auth.mixins import LoginRequiredMixin class MyView(LoginRequiredMixin, View): login_url = '/login/' redirect_field_name = 'redirect_to' .. note:: Just as the ``login_required`` decorator, this mixin does NOT check the ``is_active`` flag on a user, but the default :setting:`AUTHENTICATION_BACKENDS` reject inactive users. .. currentmodule:: django.contrib.auth.decorators Limiting access to logged-in users that pass a test ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To limit access based on certain permissions or some other test, you'd do essentially the same thing as described in the previous section. The simple way is to run your test on :attr:`request.user ` in the view directly. For example, this view checks to make sure the user has an email in the desired domain and if not, redirects to the login page:: from django.shortcuts import redirect def my_view(request): if not request.user.email.endswith('@example.com'): return redirect('/login/?next=%s' % request.path) # ... .. function:: user_passes_test(test_func, login_url=None, redirect_field_name='next') As a shortcut, you can use the convenient ``user_passes_test`` decorator which performs a redirect when the callable returns ``False``:: from django.contrib.auth.decorators import user_passes_test def email_check(user): return user.email.endswith('@example.com') @user_passes_test(email_check) def my_view(request): ... :func:`~django.contrib.auth.decorators.user_passes_test` takes a required argument: a callable that takes a :class:`~django.contrib.auth.models.User` object and returns ``True`` if the user is allowed to view the page. Note that :func:`~django.contrib.auth.decorators.user_passes_test` does not automatically check that the :class:`~django.contrib.auth.models.User` is not anonymous. :func:`~django.contrib.auth.decorators.user_passes_test` takes two optional arguments: ``login_url`` Lets you specify the URL that users who don't pass the test will be redirected to. It may be a login page and defaults to :setting:`settings.LOGIN_URL ` if you don't specify one. ``redirect_field_name`` Same as for :func:`~django.contrib.auth.decorators.login_required`. Setting it to ``None`` removes it from the URL, which you may want to do if you are redirecting users that don't pass the test to a non-login page where there's no "next page". For example:: @user_passes_test(email_check, login_url='/login/') def my_view(request): ... .. currentmodule:: django.contrib.auth.mixins .. class:: UserPassesTestMixin When using :doc:`class-based views `, you can use the ``UserPassesTestMixin`` to do this. .. method:: test_func() You have to override the ``test_func()`` method of the class to provide the test that is performed. Furthermore, you can set any of the parameters of :class:`~django.contrib.auth.mixins.AccessMixin` to customize the handling of unauthorized users:: from django.contrib.auth.mixins import UserPassesTestMixin class MyView(UserPassesTestMixin, View): def test_func(self): return self.request.user.email.endswith('@example.com') .. method:: get_test_func() You can also override the ``get_test_func()`` method to have the mixin use a differently named function for its checks (instead of :meth:`test_func`). .. admonition:: Stacking ``UserPassesTestMixin`` Due to the way ``UserPassesTestMixin`` is implemented, you cannot stack them in your inheritance list. The following does NOT work:: class TestMixin1(UserPassesTestMixin): def test_func(self): return self.request.user.email.endswith('@example.com') class TestMixin2(UserPassesTestMixin): def test_func(self): return self.request.user.username.startswith('django') class MyView(TestMixin1, TestMixin2, View): ... If ``TestMixin1`` would call ``super()`` and take that result into account, ``TestMixin1`` wouldn't work standalone anymore. .. currentmodule:: django.contrib.auth.decorators The ``permission_required`` decorator ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .. function:: permission_required(perm, login_url=None, raise_exception=False) It's a relatively common task to check whether a user has a particular permission. For that reason, Django provides a shortcut for that case: the :func:`~django.contrib.auth.decorators.permission_required()` decorator.:: from django.contrib.auth.decorators import permission_required @permission_required('polls.can_vote') def my_view(request): ... Just like the :meth:`~django.contrib.auth.models.User.has_perm` method, permission names take the form ``"."`` (i.e. ``polls.can_vote`` for a permission on a model in the ``polls`` application). The decorator may also take an iterable of permissions, in which case the user must have all of the permissions in order to access the view. Note that :func:`~django.contrib.auth.decorators.permission_required()` also takes an optional ``login_url`` parameter:: from django.contrib.auth.decorators import permission_required @permission_required('polls.can_vote', login_url='/loginpage/') def my_view(request): ... As in the :func:`~django.contrib.auth.decorators.login_required` decorator, ``login_url`` defaults to :setting:`settings.LOGIN_URL `. If the ``raise_exception`` parameter is given, the decorator will raise :exc:`~django.core.exceptions.PermissionDenied`, prompting :ref:`the 403 (HTTP Forbidden) view` instead of redirecting to the login page. If you want to use ``raise_exception`` but also give your users a chance to login first, you can add the :func:`~django.contrib.auth.decorators.login_required` decorator:: from django.contrib.auth.decorators import login_required, permission_required @login_required @permission_required('polls.can_vote', raise_exception=True) def my_view(request): ... .. currentmodule:: django.contrib.auth.mixins The ``PermissionRequiredMixin`` mixin ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To apply permission checks to :doc:`class-based views `, you can use the ``PermissionRequiredMixin``: .. class:: PermissionRequiredMixin This mixin, just like the ``permission_required`` decorator, checks whether the user accessing a view has all given permissions. You should specify the permission (or an iterable of permissions) using the ``permission_required`` parameter:: from django.contrib.auth.mixins import PermissionRequiredMixin class MyView(PermissionRequiredMixin, View): permission_required = 'polls.can_vote' # Or multiple of permissions: permission_required = ('polls.can_open', 'polls.can_edit') You can set any of the parameters of :class:`~django.contrib.auth.mixins.AccessMixin` to customize the handling of unauthorized users. You may also override these methods: .. method:: get_permission_required() Returns an iterable of permission names used by the mixin. Defaults to the ``permission_required`` attribute, converted to a tuple if necessary. .. method:: has_permission() Returns a boolean denoting whether the current user has permission to execute the decorated view. By default, this returns the result of calling :meth:`~django.contrib.auth.models.User.has_perms()` with the list of permissions returned by :meth:`get_permission_required()`. Redirecting unauthorized requests in class-based views ------------------------------------------------------ To ease the handling of access restrictions in :doc:`class-based views `, the ``AccessMixin`` can be used to redirect a user to the login page or issue an HTTP 403 Forbidden response. .. class:: AccessMixin .. attribute:: login_url Default return value for :meth:`get_login_url`. Defaults to ``None`` in which case :meth:`get_login_url` falls back to :setting:`settings.LOGIN_URL `. .. attribute:: permission_denied_message Default return value for :meth:`get_permission_denied_message`. Defaults to an empty string. .. attribute:: redirect_field_name Default return value for :meth:`get_redirect_field_name`. Defaults to ``"next"``. .. attribute:: raise_exception If this attribute is set to ``True``, a :class:`~django.core.exceptions.PermissionDenied` exception will be raised instead of the redirect. Defaults to ``False``. .. method:: get_login_url() Returns the URL that users who don't pass the test will be redirected to. Returns :attr:`login_url` if set, or :setting:`settings.LOGIN_URL ` otherwise. .. method:: get_permission_denied_message() When :attr:`raise_exception` is ``True``, this method can be used to control the error message passed to the error handler for display to the user. Returns the :attr:`permission_denied_message` attribute by default. .. method:: get_redirect_field_name() Returns the name of the query parameter that will contain the URL the user should be redirected to after a successful login. If you set this to ``None``, a query parameter won't be added. Returns the :attr:`redirect_field_name` attribute by default. .. method:: handle_no_permission() Depending on the value of ``raise_exception``, the method either raises a :exc:`~django.core.exceptions.PermissionDenied` exception or redirects the user to the ``login_url``, optionally including the ``redirect_field_name`` if it is set. .. currentmodule:: django.contrib.auth .. _session-invalidation-on-password-change: Session invalidation on password change ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If your :setting:`AUTH_USER_MODEL` inherits from :class:`~django.contrib.auth.models.AbstractBaseUser` or implements its own :meth:`~django.contrib.auth.models.AbstractBaseUser.get_session_auth_hash()` method, authenticated sessions will include the hash returned by this function. In the :class:`~django.contrib.auth.models.AbstractBaseUser` case, this is an HMAC of the password field. Django verifies that the hash in the session for each request matches the one that's computed during the request. This allows a user to log out all of their sessions by changing their password. The default password change views included with Django, :class:`~django.contrib.auth.views.PasswordChangeView` and the ``user_change_password`` view in the :mod:`django.contrib.auth` admin, update the session with the new password hash so that a user changing their own password won't log themselves out. If you have a custom password change view and wish to have similar behavior, use the :func:`update_session_auth_hash` function. .. function:: update_session_auth_hash(request, user) This function takes the current request and the updated user object from which the new session hash will be derived and updates the session hash appropriately. It also rotates the session key so that a stolen session cookie will be invalidated. Example usage:: from django.contrib.auth import update_session_auth_hash def password_change(request): if request.method == 'POST': form = PasswordChangeForm(user=request.user, data=request.POST) if form.is_valid(): form.save() update_session_auth_hash(request, form.user) else: ... .. note:: Since :meth:`~django.contrib.auth.models.AbstractBaseUser.get_session_auth_hash()` is based on :setting:`SECRET_KEY`, updating your site to use a new secret will invalidate all existing sessions. .. _built-in-auth-views: Authentication Views -------------------- .. module:: django.contrib.auth.views Django provides several views that you can use for handling login, logout, and password management. These make use of the :ref:`stock auth forms ` but you can pass in your own forms as well. Django provides no default template for the authentication views. You should create your own templates for the views you want to use. The template context is documented in each view, see :ref:`all-authentication-views`. .. _using-the-views: Using the views ~~~~~~~~~~~~~~~ There are different methods to implement these views in your project. The easiest way is to include the provided URLconf in ``django.contrib.auth.urls`` in your own URLconf, for example:: urlpatterns = [ path('accounts/', include('django.contrib.auth.urls')), ] This will include the following URL patterns:: accounts/login/ [name='login'] accounts/logout/ [name='logout'] accounts/password_change/ [name='password_change'] accounts/password_change/done/ [name='password_change_done'] accounts/password_reset/ [name='password_reset'] accounts/password_reset/done/ [name='password_reset_done'] accounts/reset/// [name='password_reset_confirm'] accounts/reset/done/ [name='password_reset_complete'] The views provide a URL name for easier reference. See :doc:`the URL documentation ` for details on using named URL patterns. If you want more control over your URLs, you can reference a specific view in your URLconf:: from django.contrib.auth import views as auth_views urlpatterns = [ path('change-password/', auth_views.PasswordChangeView.as_view()), ] The views have optional arguments you can use to alter the behavior of the view. For example, if you want to change the template name a view uses, you can provide the ``template_name`` argument. A way to do this is to provide keyword arguments in the URLconf, these will be passed on to the view. For example:: urlpatterns = [ path( 'change-password/', auth_views.PasswordChangeView.as_view(template_name='change-password.html'), ), ] All views are :doc:`class-based `, which allows you to easily customize them by subclassing. .. _all-authentication-views: All authentication views ~~~~~~~~~~~~~~~~~~~~~~~~ This is a list with all the views ``django.contrib.auth`` provides. For implementation details see :ref:`using-the-views`. .. class:: LoginView **URL name:** ``login`` See :doc:`the URL documentation ` for details on using named URL patterns. **Attributes:** * ``template_name``: The name of a template to display for the view used to log the user in. Defaults to :file:`registration/login.html`. * ``redirect_field_name``: The name of a ``GET`` field containing the URL to redirect to after login. Defaults to ``next``. * ``authentication_form``: A callable (typically just a form class) to use for authentication. Defaults to :class:`~django.contrib.auth.forms.AuthenticationForm`. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. * ``redirect_authenticated_user``: A boolean that controls whether or not authenticated users accessing the login page will be redirected as if they had just successfully logged in. Defaults to ``False``. .. warning:: If you enable ``redirect_authenticated_user``, other websites will be able to determine if their visitors are authenticated on your site by requesting redirect URLs to image files on your website. To avoid this "`social media fingerprinting `_" information leakage, host all images and your favicon on a separate domain. * ``success_url_allowed_hosts``: A :class:`set` of hosts, in addition to :meth:`request.get_host() `, that are safe for redirecting after login. Defaults to an empty :class:`set`. Here's what ``LoginView`` does: * If called via ``GET``, it displays a login form that POSTs to the same URL. More on this in a bit. * If called via ``POST`` with user submitted credentials, it tries to log the user in. If login is successful, the view redirects to the URL specified in ``next``. If ``next`` isn't provided, it redirects to :setting:`settings.LOGIN_REDIRECT_URL ` (which defaults to ``/accounts/profile/``). If login isn't successful, it redisplays the login form. It's your responsibility to provide the html for the login template , called ``registration/login.html`` by default. This template gets passed four template context variables: * ``form``: A :class:`~django.forms.Form` object representing the :class:`~django.contrib.auth.forms.AuthenticationForm`. * ``next``: The URL to redirect to after successful login. This may contain a query string, too. * ``site``: The current :class:`~django.contrib.sites.models.Site`, according to the :setting:`SITE_ID` setting. If you don't have the site framework installed, this will be set to an instance of :class:`~django.contrib.sites.requests.RequestSite`, which derives the site name and domain from the current :class:`~django.http.HttpRequest`. * ``site_name``: An alias for ``site.name``. If you don't have the site framework installed, this will be set to the value of :attr:`request.META['SERVER_NAME'] `. For more on sites, see :doc:`/ref/contrib/sites`. If you'd prefer not to call the template :file:`registration/login.html`, you can pass the ``template_name`` parameter via the extra arguments to the ``as_view`` method in your URLconf. For example, this URLconf line would use :file:`myapp/login.html` instead:: path('accounts/login/', auth_views.LoginView.as_view(template_name='myapp/login.html')), You can also specify the name of the ``GET`` field which contains the URL to redirect to after login using ``redirect_field_name``. By default, the field is called ``next``. Here's a sample :file:`registration/login.html` template you can use as a starting point. It assumes you have a :file:`base.html` template that defines a ``content`` block: .. code-block:: html+django {% extends "base.html" %} {% block content %} {% if form.errors %}

Your username and password didn't match. Please try again.

{% endif %} {% if next %} {% if user.is_authenticated %}

Your account doesn't have access to this page. To proceed, please login with an account that has access.

{% else %}

Please login to see this page.

{% endif %} {% endif %}
{% csrf_token %}
{{ form.username.label_tag }} {{ form.username }}
{{ form.password.label_tag }} {{ form.password }}
{# Assumes you setup the password_reset view in your URLconf #}

Lost password?

{% endblock %} If you have customized authentication (see :doc:`Customizing Authentication `) you can use a custom authentication form by setting the ``authentication_form`` attribute. This form must accept a ``request`` keyword argument in its ``__init__()`` method and provide a ``get_user()`` method which returns the authenticated user object (this method is only ever called after successful form validation). .. class:: LogoutView Logs a user out. **URL name:** ``logout`` **Attributes:** * ``next_page``: The URL to redirect to after logout. Defaults to :setting:`settings.LOGOUT_REDIRECT_URL `. * ``template_name``: The full name of a template to display after logging the user out. Defaults to :file:`registration/logged_out.html`. * ``redirect_field_name``: The name of a ``GET`` field containing the URL to redirect to after log out. Defaults to ``next``. Overrides the ``next_page`` URL if the given ``GET`` parameter is passed. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. * ``success_url_allowed_hosts``: A :class:`set` of hosts, in addition to :meth:`request.get_host() `, that are safe for redirecting after logout. Defaults to an empty :class:`set`. **Template context:** * ``title``: The string "Logged out", localized. * ``site``: The current :class:`~django.contrib.sites.models.Site`, according to the :setting:`SITE_ID` setting. If you don't have the site framework installed, this will be set to an instance of :class:`~django.contrib.sites.requests.RequestSite`, which derives the site name and domain from the current :class:`~django.http.HttpRequest`. * ``site_name``: An alias for ``site.name``. If you don't have the site framework installed, this will be set to the value of :attr:`request.META['SERVER_NAME'] `. For more on sites, see :doc:`/ref/contrib/sites`. .. function:: logout_then_login(request, login_url=None) Logs a user out, then redirects to the login page. **URL name:** No default URL provided **Optional arguments:** * ``login_url``: The URL of the login page to redirect to. Defaults to :setting:`settings.LOGIN_URL ` if not supplied. .. class:: PasswordChangeView **URL name:** ``password_change`` Allows a user to change their password. **Attributes:** * ``template_name``: The full name of a template to use for displaying the password change form. Defaults to :file:`registration/password_change_form.html` if not supplied. * ``success_url``: The URL to redirect to after a successful password change. * ``form_class``: A custom "change password" form which must accept a ``user`` keyword argument. The form is responsible for actually changing the user's password. Defaults to :class:`~django.contrib.auth.forms.PasswordChangeForm`. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. **Template context:** * ``form``: The password change form (see ``form_class`` above). .. class:: PasswordChangeDoneView **URL name:** ``password_change_done`` The page shown after a user has changed their password. **Attributes:** * ``template_name``: The full name of a template to use. Defaults to :file:`registration/password_change_done.html` if not supplied. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. .. class:: PasswordResetView **URL name:** ``password_reset`` Allows a user to reset their password by generating a one-time use link that can be used to reset the password, and sending that link to the user's registered email address. If the email address provided does not exist in the system, this view won't send an email, but the user won't receive any error message either. This prevents information leaking to potential attackers. If you want to provide an error message in this case, you can subclass :class:`~django.contrib.auth.forms.PasswordResetForm` and use the ``form_class`` attribute. Users flagged with an unusable password (see :meth:`~django.contrib.auth.models.User.set_unusable_password()` aren't allowed to request a password reset to prevent misuse when using an external authentication source like LDAP. Note that they won't receive any error message since this would expose their account's existence but no mail will be sent either. **Attributes:** * ``template_name``: The full name of a template to use for displaying the password reset form. Defaults to :file:`registration/password_reset_form.html` if not supplied. * ``form_class``: Form that will be used to get the email of the user to reset the password for. Defaults to :class:`~django.contrib.auth.forms.PasswordResetForm`. * ``email_template_name``: The full name of a template to use for generating the email with the reset password link. Defaults to :file:`registration/password_reset_email.html` if not supplied. * ``subject_template_name``: The full name of a template to use for the subject of the email with the reset password link. Defaults to :file:`registration/password_reset_subject.txt` if not supplied. * ``token_generator``: Instance of the class to check the one time link. This will default to ``default_token_generator``, it's an instance of ``django.contrib.auth.tokens.PasswordResetTokenGenerator``. * ``success_url``: The URL to redirect to after a successful password reset request. * ``from_email``: A valid email address. By default Django uses the :setting:`DEFAULT_FROM_EMAIL`. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. * ``html_email_template_name``: The full name of a template to use for generating a ``text/html`` multipart email with the password reset link. By default, HTML email is not sent. * ``extra_email_context``: A dictionary of context data that will be available in the email template. **Template context:** * ``form``: The form (see ``form_class`` above) for resetting the user's password. **Email template context:** * ``email``: An alias for ``user.email`` * ``user``: The current :class:`~django.contrib.auth.models.User`, according to the ``email`` form field. Only active users are able to reset their passwords (``User.is_active is True``). * ``site_name``: An alias for ``site.name``. If you don't have the site framework installed, this will be set to the value of :attr:`request.META['SERVER_NAME'] `. For more on sites, see :doc:`/ref/contrib/sites`. * ``domain``: An alias for ``site.domain``. If you don't have the site framework installed, this will be set to the value of ``request.get_host()``. * ``protocol``: http or https * ``uid``: The user's primary key encoded in base 64. * ``token``: Token to check that the reset link is valid. Sample ``registration/password_reset_email.html`` (email body template): .. code-block:: html+django Someone asked for password reset for email {{ email }}. Follow the link below: {{ protocol}}://{{ domain }}{% url 'password_reset_confirm' uidb64=uid token=token %} The same template context is used for subject template. Subject must be single line plain text string. .. class:: PasswordResetDoneView **URL name:** ``password_reset_done`` The page shown after a user has been emailed a link to reset their password. This view is called by default if the :class:`PasswordResetView` doesn't have an explicit ``success_url`` URL set. .. note:: If the email address provided does not exist in the system, the user is inactive, or has an unusable password, the user will still be redirected to this view but no email will be sent. **Attributes:** * ``template_name``: The full name of a template to use. Defaults to :file:`registration/password_reset_done.html` if not supplied. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. .. class:: PasswordResetConfirmView **URL name:** ``password_reset_confirm`` Presents a form for entering a new password. **Keyword arguments from the URL:** * ``uidb64``: The user's id encoded in base 64. * ``token``: Token to check that the password is valid. **Attributes:** * ``template_name``: The full name of a template to display the confirm password view. Default value is :file:`registration/password_reset_confirm.html`. * ``token_generator``: Instance of the class to check the password. This will default to ``default_token_generator``, it's an instance of ``django.contrib.auth.tokens.PasswordResetTokenGenerator``. * ``post_reset_login``: A boolean indicating if the user should be automatically authenticated after a successful password reset. Defaults to ``False``. * ``post_reset_login_backend``: A dotted path to the authentication backend to use when authenticating a user if ``post_reset_login`` is ``True``. Required only if you have multiple :setting:`AUTHENTICATION_BACKENDS` configured. Defaults to ``None``. * ``form_class``: Form that will be used to set the password. Defaults to :class:`~django.contrib.auth.forms.SetPasswordForm`. * ``success_url``: URL to redirect after the password reset done. Defaults to ``'password_reset_complete'``. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. **Template context:** * ``form``: The form (see ``set_password_form`` above) for setting the new user's password. * ``validlink``: Boolean, True if the link (combination of ``uidb64`` and ``token``) is valid or unused yet. .. class:: PasswordResetCompleteView **URL name:** ``password_reset_complete`` Presents a view which informs the user that the password has been successfully changed. **Attributes:** * ``template_name``: The full name of a template to display the view. Defaults to :file:`registration/password_reset_complete.html`. * ``extra_context``: A dictionary of context data that will be added to the default context data passed to the template. Helper functions ---------------- .. currentmodule:: django.contrib.auth.views .. function:: redirect_to_login(next, login_url=None, redirect_field_name='next') Redirects to the login page, and then back to another URL after a successful login. **Required arguments:** * ``next``: The URL to redirect to after a successful login. **Optional arguments:** * ``login_url``: The URL of the login page to redirect to. Defaults to :setting:`settings.LOGIN_URL ` if not supplied. * ``redirect_field_name``: The name of a ``GET`` field containing the URL to redirect to after log out. Overrides ``next`` if the given ``GET`` parameter is passed. .. _built-in-auth-forms: Built-in forms -------------- .. module:: django.contrib.auth.forms If you don't want to use the built-in views, but want the convenience of not having to write forms for this functionality, the authentication system provides several built-in forms located in :mod:`django.contrib.auth.forms`: .. note:: The built-in authentication forms make certain assumptions about the user model that they are working with. If you're using a :ref:`custom user model `, it may be necessary to define your own forms for the authentication system. For more information, refer to the documentation about :ref:`using the built-in authentication forms with custom user models `. .. class:: AdminPasswordChangeForm A form used in the admin interface to change a user's password. Takes the ``user`` as the first positional argument. .. class:: AuthenticationForm A form for logging a user in. Takes ``request`` as its first positional argument, which is stored on the form instance for use by sub-classes. .. method:: confirm_login_allowed(user) By default, ``AuthenticationForm`` rejects users whose ``is_active`` flag is set to ``False``. You may override this behavior with a custom policy to determine which users can log in. Do this with a custom form that subclasses ``AuthenticationForm`` and overrides the ``confirm_login_allowed()`` method. This method should raise a :exc:`~django.core.exceptions.ValidationError` if the given user may not log in. For example, to allow all users to log in regardless of "active" status:: from django.contrib.auth.forms import AuthenticationForm class AuthenticationFormWithInactiveUsersOkay(AuthenticationForm): def confirm_login_allowed(self, user): pass (In this case, you'll also need to use an authentication backend that allows inactive users, such as as :class:`~django.contrib.auth.backends.AllowAllUsersModelBackend`.) Or to allow only some active users to log in:: class PickyAuthenticationForm(AuthenticationForm): def confirm_login_allowed(self, user): if not user.is_active: raise forms.ValidationError( _("This account is inactive."), code='inactive', ) if user.username.startswith('b'): raise forms.ValidationError( _("Sorry, accounts starting with 'b' aren't welcome here."), code='no_b_users', ) .. class:: PasswordChangeForm A form for allowing a user to change their password. .. class:: PasswordResetForm A form for generating and emailing a one-time use link to reset a user's password. .. method:: send_mail(subject_template_name, email_template_name, context, from_email, to_email, html_email_template_name=None) Uses the arguments to send an ``EmailMultiAlternatives``. Can be overridden to customize how the email is sent to the user. :param subject_template_name: the template for the subject. :param email_template_name: the template for the email body. :param context: context passed to the ``subject_template``, ``email_template``, and ``html_email_template`` (if it is not ``None``). :param from_email: the sender's email. :param to_email: the email of the requester. :param html_email_template_name: the template for the HTML body; defaults to ``None``, in which case a plain text email is sent. By default, ``save()`` populates the ``context`` with the same variables that :class:`~django.contrib.auth.views.PasswordResetView` passes to its email context. .. class:: SetPasswordForm A form that lets a user change their password without entering the old password. .. class:: UserChangeForm A form used in the admin interface to change a user's information and permissions. .. class:: UserCreationForm A :class:`~django.forms.ModelForm` for creating a new user. It has three fields: one named after the :attr:`~django.contrib.auth.models.CustomUser.USERNAME_FIELD` from the user model, and ``password1`` and ``password2``. It verifies that ``password1`` and ``password2`` match, validates the password using :func:`~django.contrib.auth.password_validation.validate_password`, and sets the user's password using :meth:`~django.contrib.auth.models.User.set_password()`. .. currentmodule:: django.contrib.auth Authentication data in templates -------------------------------- The currently logged-in user and their permissions are made available in the :doc:`template context ` when you use :class:`~django.template.RequestContext`. .. admonition:: Technicality Technically, these variables are only made available in the template context if you use :class:`~django.template.RequestContext` and the ``'django.contrib.auth.context_processors.auth'`` context processor is enabled. It is in the default generated settings file. For more, see the :ref:`RequestContext docs `. Users ~~~~~ When rendering a template :class:`~django.template.RequestContext`, the currently logged-in user, either a :class:`~django.contrib.auth.models.User` instance or an :class:`~django.contrib.auth.models.AnonymousUser` instance, is stored in the template variable ``{{ user }}``: .. code-block:: html+django {% if user.is_authenticated %}

Welcome, {{ user.username }}. Thanks for logging in.

{% else %}

Welcome, new user. Please log in.

{% endif %} This template context variable is not available if a ``RequestContext`` is not being used. Permissions ~~~~~~~~~~~ The currently logged-in user's permissions are stored in the template variable ``{{ perms }}``. This is an instance of ``django.contrib.auth.context_processors.PermWrapper``, which is a template-friendly proxy of permissions. Evaluating a single-attribute lookup of ``{{ perms }}`` as a boolean is a proxy to :meth:`User.has_module_perms() `. For example, to check if the logged-in user has any permissions in the ``foo`` app:: {% if perms.foo %} Evaluating a two-level-attribute lookup as a boolean is a proxy to :meth:`User.has_perm() `. For example, to check if the logged-in user has the permission ``foo.can_vote``:: {% if perms.foo.can_vote %} Here's a more complete example of checking permissions in a template: .. code-block:: html+django {% if perms.foo %}

You have permission to do something in the foo app.

{% if perms.foo.can_vote %}

You can vote!

{% endif %} {% if perms.foo.can_drive %}

You can drive!

{% endif %} {% else %}

You don't have permission to do anything in the foo app.

{% endif %} It is possible to also look permissions up by ``{% if in %}`` statements. For example: .. code-block:: html+django {% if 'foo' in perms %} {% if 'foo.can_vote' in perms %}

In lookup works, too.

{% endif %} {% endif %} .. _auth-admin: Managing users in the admin =========================== When you have both ``django.contrib.admin`` and ``django.contrib.auth`` installed, the admin provides a convenient way to view and manage users, groups, and permissions. Users can be created and deleted like any Django model. Groups can be created, and permissions can be assigned to users or groups. A log of user edits to models made within the admin is also stored and displayed. Creating users -------------- You should see a link to "Users" in the "Auth" section of the main admin index page. The "Add user" admin page is different than standard admin pages in that it requires you to choose a username and password before allowing you to edit the rest of the user's fields. Also note: if you want a user account to be able to create users using the Django admin site, you'll need to give them permission to add users *and* change users (i.e., the "Add user" and "Change user" permissions). If an account has permission to add users but not to change them, that account won't be able to add users. Why? Because if you have permission to add users, you have the power to create superusers, which can then, in turn, change other users. So Django requires add *and* change permissions as a slight security measure. Be thoughtful about how you allow users to manage permissions. If you give a non-superuser the ability to edit users, this is ultimately the same as giving them superuser status because they will be able to elevate permissions of users including themselves! Changing passwords ------------------ User passwords are not displayed in the admin (nor stored in the database), but the :doc:`password storage details ` are displayed. Included in the display of this information is a link to a password change form that allows admins to change user passwords.