+
−=============================
+
−User authentication in Django
+
−=============================
+
−
+
−.. module:: django.contrib.auth
+
−   :synopsis: Django's authentication framework.
+
−
+
−Django comes with a user authentication system. It handles user accounts,
+
−groups, permissions and cookie-based user sessions. This document explains how
+
−things work.
+
−
+
−Overview
+
−========
+
−
+
−The auth system consists of:
+
−
+
−    * Users
+
−    * Permissions: Binary (yes/no) flags designating whether a user may perform
+
−      a certain task.
+
−    * Groups: A generic way of applying labels and permissions to more than one
+
−      user.
+
−    * Messages: A simple way to queue messages for given users.
+
−
+
−.. deprecated:: 1.2
+
−   The Messages component of the auth system will be removed in Django 1.4.
+
−
+
−Installation
+
−============
+
−
+
−Authentication support is bundled as a Django application in
+
−``django.contrib.auth``. To install it, do the following:
+
−
+
−    1. Put ``'django.contrib.auth'`` and ``'django.contrib.contenttypes'`` in
+
−       your :setting:`INSTALLED_APPS` setting.
+
−       (The :class:`~django.contrib.auth.models.Permission` model in
+
−       :mod:`django.contrib.auth` depends on :mod:`django.contrib.contenttypes`.)
+
−    2. Run the command ``manage.py syncdb``.
+
−
+
−Note that the default :file:`settings.py` file created by
+
−:djadmin:`django-admin.py startproject <startproject>` includes
+
−``'django.contrib.auth'`` and ``'django.contrib.contenttypes'`` in
+
−:setting:`INSTALLED_APPS` for convenience.  If your :setting:`INSTALLED_APPS`
+
−already contains these apps, feel free to run :djadmin:`manage.py syncdb
+
−<syncdb>` again; you can run that command as many times as you'd like, and each
+
−time it'll only install what's needed.
+
−
+
−The :djadmin:`syncdb` command creates the necessary database tables, creates
+
−permission objects for all installed apps that need 'em, and prompts you to
+
−create a superuser account the first time you run it.
+
−
+
−Once you've taken those steps, that's it.
+
−
+
−Users
+
−=====
+
−
+
−.. class:: models.User
+
−
+
−API reference
+
−-------------
+
−
+
−Fields
+
−~~~~~~
+
−
+
−.. class:: models.User
+
−
+
−    :class:`~django.contrib.auth.models.User` objects have the following
+
−    fields:
+
−
+
−    .. attribute:: models.User.username
+
−
+
−        Required. 30 characters or fewer. Alphanumeric characters only
+
−        (letters, digits and underscores).
+
−
+
−        .. versionchanged:: 1.2
+
−           Usernames may now contain ``@``, ``+``, ``.`` and ``-`` characters.
+
−
+
−    .. attribute:: models.User.first_name
+
−
+
−        Optional. 30 characters or fewer.
+
−
+
−    .. attribute:: models.User.last_name
+
−
+
−        Optional. 30 characters or fewer.
+
−
+
−    .. attribute:: models.User.email
+
−
+
−        Optional. E-mail address.
+
−
+
−    .. attribute:: models.User.password
+
−
+
−        Required. A hash of, and metadata about, the password. (Django doesn't
+
−        store the raw password.) Raw passwords can be arbitrarily long and can
+
−        contain any character. See the "Passwords" section below.
+
−
+
−    .. attribute:: models.User.is_staff
+
−
+
−        Boolean. Designates whether this user can access the admin site.
+
−
+
−    .. attribute:: models.User.is_active
+
−
+
−        Boolean. Designates whether this user account should be considered
+
−        active. We recommend that you set this flag to ``False`` instead of
+
−        deleting accounts; that way, if your applications have any foreign keys
+
−        to users, the foreign keys won't break.
+
−
+
−        This doesn't necessarily control whether or not the user can log in.
+
−        Authentication backends aren't required to check for the ``is_active``
+
−        flag, so if you want to reject a login based on ``is_active`` being
+
−        ``False``, it's up to you to check that in your own login view.
+
−        However, the :class:`~django.contrib.auth.forms.AuthenticationForm`
+
−        used by the :func:`~django.contrib.auth.views.login` view *does*
+
−        perform this check, as do the permission-checking methods such as
+
−        :meth:`~models.User.has_perm` and the authentication in the Django
+
−        admin. All of those functions/methods will return ``False`` for
+
−        inactive users.
+
−
+
−    .. attribute:: models.User.is_superuser
+
−
+
−        Boolean. Designates that this user has all permissions without
+
−        explicitly assigning them.
+
−
+
−    .. attribute:: models.User.last_login
+
−
+
−        A datetime of the user's last login. Is set to the current date/time by
+
−        default.
+
−
+
−    .. attribute:: models.User.date_joined
+
−
+
−        A datetime designating when the account was created. Is set to the
+
−        current date/time by default when the account is created.
+
−
+
−Methods
+
−~~~~~~~
+
−
+
−.. class:: models.User
+
−
+
−    :class:`~django.contrib.auth.models.User` objects have two many-to-many
+
−    fields: models.User. ``groups`` and ``user_permissions``.
+
−    :class:`~django.contrib.auth.models.User` objects can access their related
+
−    objects in the same way as any other :doc:`Django model
+
−    </topics/db/models>`:
+
−
+
−    .. code-block:: python
+
−
+
−        myuser.groups = [group_list]
+
−        myuser.groups.add(group, group, ...)
+
−        myuser.groups.remove(group, group, ...)
+
−        myuser.groups.clear()
+
−        myuser.user_permissions = [permission_list]
+
−        myuser.user_permissions.add(permission, permission, ...)
+
−        myuser.user_permissions.remove(permission, permission, ...)
+
−        myuser.user_permissions.clear()
+
−
+
−    In addition to those automatic API methods,
+
−    :class:`~django.contrib.auth.models.User` objects have the following custom
+
−    methods:
+
−
+
−    .. method:: models.User.is_anonymous()
+
−
+
−        Always returns ``False``. This is a way of differentiating
+
−        :class:`~django.contrib.auth.models.User` and
+
−        :class:`~django.contrib.auth.models.AnonymousUser` objects.
+
−        Generally, you should prefer using
+
−        :meth:`~django.contrib.auth.models.User.is_authenticated()` to this
+
−        method.
+
−
+
−    .. method:: models.User.is_authenticated()
+
−
+
−        Always returns ``True``. This is a way to tell if the user has been
+
−        authenticated. This does not imply any permissions, and doesn't check
+
−        if the user is active - it only indicates that the user has provided a
+
−        valid username and password.
+
−
+
−    .. method:: models.User.get_full_name()
+
−
+
−        Returns the :attr:`~django.contrib.auth.models.User.first_name` plus
+
−        the :attr:`~django.contrib.auth.models.User.last_name`, with a space in
+
−        between.
+
−
+
−    .. method:: models.User.set_password(raw_password)
+
−
+
−        Sets the user's password to the given raw string, taking care of the
+
−        password hashing. Doesn't save the
+
−        :class:`~django.contrib.auth.models.User` object.
+
−
+
−    .. method:: models.User.check_password(raw_password)
+
−
+
−        Returns ``True`` if the given raw string is the correct password for
+
−        the user. (This takes care of the password hashing in making the
+
−        comparison.)
+
−
+
−    .. method:: models.User.set_unusable_password()
+
−
+
−        .. versionadded:: 1.0
+
−
+
−        Marks the user as having no password set.  This isn't the same as
+
−        having a blank string for a password.
+
−        :meth:`~django.contrib.auth.models.User.check_password()` for this user
+
−        will never return ``True``. Doesn't save the
+
−        :class:`~django.contrib.auth.models.User` object.
+
−
+
−        You may need this if authentication for your application takes place
+
−        against an existing external source such as an LDAP directory.
+
−
+
−    .. method:: models.User.has_usable_password()
+
−
+
−        .. versionadded:: 1.0
+
−
+
−        Returns ``False`` if
+
−        :meth:`~django.contrib.auth.models.User.set_unusable_password()` has
+
−        been called for this user.
+
−
+
−    .. method:: models.User.get_group_permissions(obj=None)
+
−
+
−        Returns a set of permission strings that the user has, through his/her
+
−        groups.
+
−
+
−        .. versionadded:: 1.2
+
−
+
−        If ``obj`` is passed in, only returns the group permissions for
+
−        this specific object.
+
−
+
−    .. method:: models.User.get_all_permissions(obj=None)
+
−
+
−        Returns a set of permission strings that the user has, both through
+
−        group and user permissions.
+
−
+
−        .. versionadded:: 1.2
+
−
+
−        If ``obj`` is passed in, only returns the permissions for this
+
−        specific object.
+
−
+
−    .. method:: models.User.has_perm(perm, obj=None)
+
−
+
−        Returns ``True`` if the user has the specified permission, where perm is
+
−        in the format ``"<app label>.<permission codename>"``. (see
+
−        `permissions`_ section below). If the user is inactive, this method will
+
−        always return ``False``.
+
−
+
−        .. versionadded:: 1.2
+
−
+
−        If ``obj`` is passed in, this method won't check for a permission for
+
−        the model, but for this specific object.
+
−
+
−    .. method:: models.User.has_perms(perm_list, obj=None)
+
−
+
−        Returns ``True`` if the user has each of the specified permissions,
+
−        where each perm is in the format
+
−        ``"<app label>.<permission codename>"``. If the user is inactive,
+
−        this method will always return ``False``.
+
−
+
−        .. versionadded:: 1.2
+
−
+
−        If ``obj`` is passed in, this method won't check for permissions for
+
−        the model, but for the specific object.
+
−
+
−    .. method:: models.User.has_module_perms(package_name)
+
−
+
−        Returns ``True`` if the user has any permissions in the given package
+
−        (the Django app label). If the user is inactive, this method will
+
−        always return ``False``.
+
−
+
−    .. method:: models.User.get_and_delete_messages()
+
−
+
−        Returns a list of :class:`~django.contrib.auth.models.Message` objects
+
−        in the user's queue and deletes the messages from the queue.
+
−
+
−    .. method:: models.User.email_user(subject, message, from_email=None)
+
−
+
−        Sends an e-mail to the user. If
+
−        :attr:`~django.contrib.auth.models.User.from_email` is ``None``, Django
+
−        uses the :setting:`DEFAULT_FROM_EMAIL`.
+
−
+
−    .. method:: models.User.get_profile()
+
−
+
−        Returns a site-specific profile for this user. Raises
+
−        :exc:`django.contrib.auth.models.SiteProfileNotAvailable` if the
+
−        current site doesn't allow profiles. For information on how to define a
+
−        site-specific user profile, see the section on `storing additional user
+
−        information`_ below.
+
−
+
−.. _storing additional user information: #storing-additional-information-about-users
+
−
+
−Manager functions
+
−~~~~~~~~~~~~~~~~~
+
−
+
−.. class:: models.UserManager
+
−
+
−    The :class:`~django.contrib.auth.models.User` model has a custom manager
+
−    that has the following helper functions:
+
−
+
−    .. method:: models.UserManager.create_user(username, email, password=None)
+
−
+
−        Creates, saves and returns a :class:`~django.contrib.auth.models.User`.
+
−
+
−        The :attr:`~django.contrib.auth.models.User.username` and
+
−        :attr:`~django.contrib.auth.models.User.password` are set as given. The
+
−        domain portion of :attr:`~django.contrib.auth.models.User.email` is
+
−        automatically convered to lowercase, and the returned
+
−        :class:`~django.contrib.auth.models.User` object will have
+
−        :attr:`~models.User.is_active` set to ``True``.
+
−
+
−        If no password is provided,
+
−        :meth:`~django.contrib.auth.models.User.set_unusable_password()` will
+
−        be called.
+
−
+
−        See `Creating users`_ for example usage.
+
−
+
−    .. method:: models.UserManager.make_random_password(length=10, allowed_chars='abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789')
+
−
+
−        Returns a random password with the given length and given string of
+
−        allowed characters. (Note that the default value of ``allowed_chars``
+
−        doesn't contain letters that can cause user confusion, including:
+
−
+
−            * ``i``, ``l``, ``I``, and ``1`` (lowercase letter i, lowercase
+
−              letter L, uppercase letter i, and the number one)
+
−            * ``o``, ``O``, and ``0`` (uppercase letter o, lowercase letter o,
+
−              and zero)
+
−
+
−Basic usage
+
−-----------
+
−
+
−.. _topics-auth-creating-users:
+
−
+
−Creating users
+
−~~~~~~~~~~~~~~
+
−
+
−The most basic way to create users is to use the
+
−:meth:`~django.contrib.auth.models.UserManager.create_user` helper function
+
−that comes with Django::
+
−
+
−    >>> 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.is_staff = True
+
−    >>> user.save()
+
−
+
−You can also create users using the Django admin site. Assuming you've enabled
+
−the admin site and hooked it to the URL ``/admin/``, the "Add user" page is at
+
−``/admin/auth/user/add/``. You should also 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 your own user account to be able to create users using
+
−the Django admin site, you'll need to give yourself permission to add users
+
−*and* change users (i.e., the "Add user" and "Change user" permissions). If
+
−your account has permission to add users but not to change them, you 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.
+
−
+
−Changing passwords
+
−~~~~~~~~~~~~~~~~~~
+
−
+
−.. versionadded:: 1.2
+
−   The ``manage.py changepassword`` command was added.
+
−
+
−:djadmin:`manage.py changepassword *username* <changepassword>` offers a method
+
−of changing a User's password from the command line. It prompts you to
+
−change the password of a given user which you must enter twice. If
+
−they both match, the new password will be changed immediately. If you
+
−do not supply a user, the command will attempt to change the password
+
−whose username matches the current user.
+
−
+
−You can also change a password programmatically, using
+
−:meth:`~django.contrib.auth.models.User.set_password()`:
+
−
+
−.. code-block:: python
+
−
+
−    >>> from django.contrib.auth.models import User
+
−    >>> u = User.objects.get(username__exact='john')
+
−    >>> u.set_password('new password')
+
−    >>> u.save()
+
−
+
−Don't set the :attr:`~django.contrib.auth.models.User.password` attribute
+
−directly unless you know what you're doing. This is explained in the next
+
−section.
+
−
+
−Passwords
+
−---------
+
−
+
−The :attr:`~django.contrib.auth.models.User.password` attribute of a
+
−:class:`~django.contrib.auth.models.User` object is a string in this format::
+
−
+
−    hashtype$salt$hash
+
−
+
−That's hashtype, salt and hash, separated by the dollar-sign character.
+
−
+
−Hashtype is either ``sha1`` (default), ``md5`` or ``crypt`` -- the algorithm
+
−used to perform a one-way hash of the password. Salt is a random string used
+
−to salt the raw password to create the hash. Note that the ``crypt`` method is
+
−only supported on platforms that have the standard Python ``crypt`` module
+
−available.
+
−
+
−.. versionadded:: 1.0
+
−    Support for the ``crypt`` module is new in Django 1.0.
+
−
+
−For example::
+
−
+
−    sha1$a1976$a36cc8cbf81742a8fb52e221aaeab48ed7f58ab4
+
−
+
−The :meth:`~django.contrib.auth.models.User.set_password` and
+
−:meth:`~django.contrib.auth.models.User.check_password` functions handle the
+
−setting and checking of these values behind the scenes.
+
−
+
−Previous Django versions, such as 0.90, used simple MD5 hashes without password
+
−salts. For backwards compatibility, those are still supported; they'll be
+
−converted automatically to the new style the first time
+
−:meth:`~django.contrib.auth.models.User.check_password()` works correctly for
+
−a given user.
+
−
+
−Anonymous users
+
−---------------
+
−
+
−.. class:: models.AnonymousUser
+
−
+
−    :class:`django.contrib.auth.models.AnonymousUser` is a class that
+
−    implements the :class:`django.contrib.auth.models.User` interface, with
+
−    these differences:
+
−
+
−    * :attr:`~django.contrib.auth.models.User.id` is always ``None``.
+
−    * :attr:`~django.contrib.auth.models.User.is_staff` and
+
−      :attr:`~django.contrib.auth.models.User.is_superuser` are always
+
−      ``False``.
+
−    * :attr:`~django.contrib.auth.models.User.is_active` is always ``False``.
+
−    * :attr:`~django.contrib.auth.models.User.groups` and
+
−      :attr:`~django.contrib.auth.models.User.user_permissions` are always
+
−      empty.
+
−    * :meth:`~django.contrib.auth.models.User.is_anonymous()` returns ``True``
+
−      instead of ``False``.
+
−    * :meth:`~django.contrib.auth.models.User.is_authenticated()` returns
+
−      ``False`` instead of ``True``.
+
−    * :meth:`~django.contrib.auth.models.User.set_password()`,
+
−      :meth:`~django.contrib.auth.models.User.check_password()`,
+
−      :meth:`~django.contrib.auth.models.User.save()`,
+
−      :meth:`~django.contrib.auth.models.User.delete()`,
+
−      :meth:`~django.contrib.auth.models.User.set_groups()` and
+
−      :meth:`~django.contrib.auth.models.User.set_permissions()` raise
+
−      :exc:`NotImplementedError`.
+
−
+
−In practice, you probably won't need to use
+
−:class:`~django.contrib.auth.models.AnonymousUser` objects on your own, but
+
−they're used by Web requests, as explained in the next section.
+
−
+
−.. _topics-auth-creating-superusers:
+
−
+
−Creating superusers
+
−-------------------
+
−
+
−.. versionadded:: 1.0
+
−   The ``manage.py createsuperuser`` command is new.
+
−
+
−:djadmin:`manage.py syncdb <syncdb>` prompts you to create a superuser the
+
−first time you run it after adding ``'django.contrib.auth'`` to your
+
−:setting:`INSTALLED_APPS`. If you need to create a superuser at a later date,
+
−you can use a command line utility::
+
−
+
−    manage.py createsuperuser --username=joe --email=joe@example.com
+
−
+
−You will be prompted for a password. After you enter one, the user will be
+
−created immediately. If you leave off the :djadminopt:`--username` or the
+
−:djadminopt:`--email` options, it will prompt you for those values.
+
−
+
−If you're using an older release of Django, the old way of creating a superuser
+
−on the command line still works::
+
−
+
−    python /path/to/django/contrib/auth/create_superuser.py
+
−
+
−...where :file:`/path/to` is the path to the Django codebase on your
+
−filesystem. The ``manage.py`` command is preferred because it figures out the
+
−correct path and environment for you.
+
−
+
−.. _auth-profiles:
+
−
+
−Storing additional information about users
+
−------------------------------------------
+
−
+
−If you'd like to store additional information related to your users, Django
+
−provides a method to specify a site-specific related model -- termed a "user
+
−profile" -- for this purpose.
+
−
+
−To make use of this feature, define a model with fields for the
+
−additional information you'd like to store, or additional methods
+
−you'd like to have available, and also add a
+
−:class:`~django.db.models.Field.OneToOneField` from your model to the
+
−:class:`~django.contrib.auth.models.User` model. This will ensure only
+
−one instance of your model can be created for each
+
−:class:`~django.contrib.auth.models.User`.
+
−
+
−To indicate that this model is the user profile model for a given site, fill in
+
−the setting :setting:`AUTH_PROFILE_MODULE` with a string consisting of the
+
−following items, separated by a dot:
+
−
+
−1. The name of the application (case sensitive) in which the user
+
−   profile model is defined (in other words, the
+
−   name which was passed to :djadmin:`manage.py startapp <startapp>` to create
+
−   the application).
+
−
+
−2. The name of the model (not case sensitive) class.
+
−
+
−For example, if the profile model was a class named ``UserProfile`` and was
+
−defined inside an application named ``accounts``, the appropriate setting would
+
−be::
+
−
+
−    AUTH_PROFILE_MODULE = 'accounts.UserProfile'
+
−
+
−When a user profile model has been defined and specified in this manner, each
+
−:class:`~django.contrib.auth.models.User` object will have a method --
+
−:class:`~django.contrib.auth.models.User.get_profile()` -- which returns the
+
−instance of the user profile model associated with that
+
−:class:`~django.contrib.auth.models.User`.
+
−
+
−The method :class:`~django.contrib.auth.models.User.get_profile()`
+
−does not create the profile, if it does not exist. You need to
+
−register a handler for the signal
+
−:attr:`django.db.models.signals.post_save` on the User model, and, in
+
−the handler, if created=True, create the associated user profile.
+
−
+
−For more information, see `Chapter 12 of the Django book`_.
+
−
+
−.. _Chapter 12 of the Django book: http://www.djangobook.com/en/1.0/chapter12/#cn222
+
−
+
−Authentication in Web requests
+
−==============================
+
−
+
−Until now, this document has dealt with the low-level APIs for manipulating
+
−authentication-related objects. On a higher level, Django can hook this
+
−authentication framework into its system of
+
−:class:`request objects <django.http.HttpRequest>`.
+
−
+
−First, install the
+
−:class:`~django.contrib.sessions.middleware.SessionMiddleware` and
+
−:class:`~django.contrib.auth.middleware.AuthenticationMiddleware`
+
−middlewares by adding them to your :setting:`MIDDLEWARE_CLASSES` setting. See
+
−the :doc:`session documentation </topics/http/sessions>` for more information.
+
−
+
−Once you have those middlewares installed, you'll be able to access
+
−:attr:`request.user <django.http.HttpRequest.user>` in views.
+
−:attr:`request.user <django.http.HttpRequest.user>` will give you a
+
−:class:`~django.contrib.auth.models.User` object representing the currently
+
−logged-in user. If a user isn't currently logged in,
+
−:attr:`request.user <django.http.HttpRequest.user>` will be set to an instance
+
−of :class:`~django.contrib.auth.models.AnonymousUser` (see the previous
+
−section). You can tell them apart with
+
−:meth:`~django.contrib.auth.models.User.is_authenticated()`, like so::
+
−
+
−    if request.user.is_authenticated():
+
−        # Do something for authenticated users.
+
−    else:
+
−        # Do something for anonymous users.
+
−
+
−.. _how-to-log-a-user-in:
+
−
+
−How to log a user in
+
−--------------------
+
−
+
−Django provides two functions in :mod:`django.contrib.auth`:
+
−:func:`~django.contrib.auth.authenticate()` and
+
−:func:`~django.contrib.auth.login()`.
+
−
+
−.. function:: authenticate()
+
−
+
−    To authenticate a given username and password, use
+
−    :func:`~django.contrib.auth.authenticate()`. It takes two keyword
+
−    arguments, ``username`` and ``password``, and it returns a
+
−    :class:`~django.contrib.auth.models.User` object if the password is valid
+
−    for the given username. If the password is invalid,
+
−    :func:`~django.contrib.auth.authenticate()` returns ``None``. Example::
+
−
+
−        from django.contrib.auth import authenticate
+
−        user = authenticate(username='john', password='secret')
+
−        if user is not None:
+
−            if user.is_active:
+
−                print "You provided a correct username and password!"
+
−            else:
+
−                print "Your account has been disabled!"
+
−        else:
+
−            print "Your username and password were incorrect."
+
−
+
−.. function:: login()
+
−
+
−    To log a user in, in a view, use :func:`~django.contrib.auth.login()`. It
+
−    takes an :class:`~django.http.HttpRequest` object and a
+
−    :class:`~django.contrib.auth.models.User` object.
+
−    :func:`~django.contrib.auth.login()` saves the user's ID in the session,
+
−    using Django's session framework, so, as mentioned above, you'll need to
+
−    make sure to have the session middleware installed.
+
−
+
−    This example shows how you might use both
+
−    :func:`~django.contrib.auth.authenticate()` and
+
−    :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(username=username, password=password)
+
−            if user is not None:
+
−                if user.is_active:
+
−                    login(request, user)
+
−                    # Redirect to a success page.
+
−                else:
+
−                    # Return a 'disabled account' error message
+
−            else:
+
−                # Return an 'invalid login' error message.
+
−
+
−.. admonition:: Calling ``authenticate()`` first
+
−
+
−    When you're manually logging a user in, you *must* call
+
−    :func:`~django.contrib.auth.authenticate()` before you call
+
−    :func:`~django.contrib.auth.login()`.
+
−    :func:`~django.contrib.auth.authenticate()`
+
−    sets an attribute on the :class:`~django.contrib.auth.models.User` noting
+
−    which authentication backend successfully authenticated that user (see the
+
−    `backends documentation`_ for details), and this information is needed
+
−    later during the login process.
+
−
+
−.. _backends documentation: #other-authentication-sources
+
−
+
−Manually checking a user's password
+
−-----------------------------------
+
−
+
−.. function:: check_password()
+
−
+
−    If you'd like to manually authenticate a user by comparing a plain-text
+
−    password to the hashed password in the database, use the convenience
+
−    function :func:`django.contrib.auth.models.check_password`. It takes two
+
−    arguments: the plain-text password to check, and the full value of a user's
+
−    ``password`` field in the database to check against, and returns ``True``
+
−    if they match, ``False`` otherwise.
+
−
+
−How to log a user out
+
−---------------------
+
−
+
−.. function:: logout()
+
−
+
−    To log out a user who has been logged in via
+
−    :func:`django.contrib.auth.login()`, use
+
−    :func:`django.contrib.auth.logout()` within your view. It takes an
+
−    :class:`~django.http.HttpRequest` object and has no return value.
+
−    Example::
+
−
+
−        from django.contrib.auth import logout
+
−
+
−        def logout_view(request):
+
−            logout(request)
+
−            # Redirect to a success page.
+
−
+
−    Note that :func:`~django.contrib.auth.logout()` doesn't throw any errors if
+
−    the user wasn't logged in.
+
−
+
−    .. versionchanged:: 1.0
+
−       Calling ``logout()`` now cleans session data.
+
−
+
−    When you call :func:`~django.contrib.auth.logout()`, the session data for
+
−    the current request is completely cleaned out. All existing data is
+
−    removed. This is to prevent another person from using the same Web browser
+
−    to log in and have access to the previous user's session data. If you want
+
−    to put anything into the session that will be available to the user
+
−    immediately after logging out, do that *after* calling
+
−    :func:`django.contrib.auth.logout()`.
+
−
+
−Limiting access to logged-in users
+
−----------------------------------
+
−
+
−The raw way
+
−~~~~~~~~~~~
+
−
+
−The simple, raw way to limit access to pages is to check
+
−:meth:`request.user.is_authenticated()
+
−<django.contrib.auth.models.User.is_authenticated()>` and either redirect to a
+
−login page::
+
−
+
−    from django.http import HttpResponseRedirect
+
−
+
−    def my_view(request):
+
−        if not request.user.is_authenticated():
+
−            return HttpResponseRedirect('/login/?next=%s' % request.path)
+
−        # ...
+
−
+
−...or display an error message::
+
−
+
−    def my_view(request):
+
−        if not request.user.is_authenticated():
+
−            return render_to_response('myapp/login_error.html')
+
−        # ...
+
−
+
−The login_required decorator
+
−~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
−
+
−.. function:: decorators.login_required([redirect_field_name=REDIRECT_FIELD_NAME])
+
−
+
−    As a shortcut, you can use the convenient
+
−    :func:`~django.contrib.auth.decorators.login_required` decorator::
+
−
+
−        from django.contrib.auth.decorators import login_required
+
−
+
−        @login_required
+
−        def my_view(request):
+
−            ...
+
−    
+
−    :func:`~django.contrib.auth.decorators.login_required` does the following:
+
−
+
−    * If the user isn't logged in, redirect to
+
−      :setting:`settings.LOGIN_URL <LOGIN_URL>`, passing the current absolute
+
−      path in the query string. Example: ``/accounts/login/?next=/polls/3/``.
+
−
+
−    * If the user is logged in, execute the view normally. The view code is
+
−      free to assume the user is logged in.
+
−
+
−    By default, the path that the user should be redirected to upon
+
−    successful authentication is stored in a query string parameter called
+
−    ``"next"``. If you would prefer to use a different name for this parameter,
+
−    :func:`~django.contrib.auth.decorators.login_required` takes an
+
−    optional ``redirect_field_name`` parameter::
+
−
+
−        from django.contrib.auth.decorators import login_required
+
−
+
−        @login_required(redirect_field_name='my_redirect_field')
+
−        def my_view(request):
+
−            ...
+
−
+
−    If you provide a value to ``redirect_field_name``, you will most
+
−    likely need to customize your login template as well, since the template
+
−    context variable which stores the redirect path will use the value of
+
−    ``redirect_field_name`` as it's key rather than ``"next"`` (the default).
+
−
+
−    Note that you'll need to map the appropriate Django view to
+
−    :setting:`settings.LOGIN_URL <LOGIN_URL>`. For example, using the defaults,
+
−    add the following line to your URLconf::
+
−
+
−        (r'^accounts/login/$', 'django.contrib.auth.views.login'),
+
−
+
−.. function:: views.login(request, [template_name, redirect_field_name, authentication_form])
+
−
+
−    Here's what ``django.contrib.auth.views.login`` 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``, 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 <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 login form in a template called
+
−    ``registration/login.html`` by default. This template gets passed four
+
−    template context variables:
+
−
+
−        * ``form``: A :class:`~django.forms.Form` object representing the login
+
−          form. See the :doc:`forms documentation </topics/forms/index>` for
+
−          more on ``Form`` objects.
+
−
+
−        * ``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.models.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'] <django.http.HttpRequest.META>`.
+
−          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 view in your URLconf. For example, this URLconf line would use
+
−    :file:`myapp/login.html` instead::
+
−
+
−        (r'^accounts/login/$', 'django.contrib.auth.views.login', {'template_name': 'myapp/login.html'}),
+
−
+
−    You can also specify the name of the ``GET`` field which contains the URL
+
−    to redirect to after login by passing ``redirect_field_name`` to the view.
+
−    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 %}
+
−        <p>Your username and password didn't match. Please try again.</p>
+
−        {% endif %}
+
−
+
−        <form method="post" action="{% url django.contrib.auth.views.login %}">
+
−        {% csrf_token %}
+
−        <table>
+
−        <tr>
+
−            <td>{{ form.username.label_tag }}</td>
+
−            <td>{{ form.username }}</td>
+
−        </tr>
+
−        <tr>
+
−            <td>{{ form.password.label_tag }}</td>
+
−            <td>{{ form.password }}</td>
+
−        </tr>
+
−        </table>
+
−
+
−        <input type="submit" value="login" />
+
−        <input type="hidden" name="next" value="{{ next }}" />
+
−        </form>
+
−
+
−        {% endblock %}
+
−
+
−    .. versionadded:: 1.2
+
−
+
−    If you are using alternate authentication (see
+
−    :ref:`authentication-backends`) you can pass a custom authentication form
+
−    to the login view via the ``authentication_form`` parameter. 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).
+
−
+
−    .. _forms documentation: ../forms/
+
−    .. _site framework docs: ../sites/
+
−
+
−Other built-in views
+
−--------------------
+
−
+
−In addition to the :func:`~views.login` view, the authentication system
+
−includes a few other useful built-in views located in
+
−:mod:`django.contrib.auth.views`:
+
−
+
−.. function:: views.logout(request, [next_page, template_name, redirect_field_name])
+
−
+
−    Logs a user out.
+
−
+
−    **Optional arguments:**
+
−
+
−        * ``next_page``: The URL to redirect to after logout.
+
−
+
−        * ``template_name``: The full name of a template to display after
+
−          logging the user out. This will default to
+
−          :file:`registration/logged_out.html` if no argument is supplied.
+
−
+
−        * ``redirect_field_name``: The name of a ``GET`` field containing the
+
−          URL to redirect to after log out. Overrides ``next_page`` if the given
+
−          ``GET`` parameter is passed.
+
−
+
−    **Template context:**
+
−
+
−        * ``title``: The string "Logged out", localized.
+
−
+
−.. function:: views.logout_then_login(request[, login_url])
+
−
+
−    Logs a user out, then redirects to the login page.
+
−
+
−    **Optional arguments:**
+
−
+
−        * ``login_url``: The URL of the login page to redirect to. This will
+
−          default to :setting:`settings.LOGIN_URL <LOGIN_URL>` if not supplied.
+
−
+
−.. function:: views.password_change(request[, template_name, post_change_redirect, password_change_form])
+
−
+
−    Allows a user to change their password.
+
−
+
−    **Optional arguments:**
+
−
+
−        * ``template_name``: The full name of a template to use for
+
−          displaying the password change form. This will default to
+
−          :file:`registration/password_change_form.html` if not supplied.
+
−
+
−        * ``post_change_redirect``: The URL to redirect to after a successful
+
−          password change.
+
−
+
−        * .. versionadded:: 1.2
+
−
+
−          ``password_change_form``: A custom "change password" form which must
+
−          accept a ``user`` keyword argument. The form is responsible for
+
−          actually changing the user's password.
+
−
+
−
+
−    **Template context:**
+
−
+
−        * ``form``: The password change form.
+
−
+
−.. function:: views.password_change_done(request[, template_name])
+
−
+
−    The page shown after a user has changed their password.
+
−
+
−    **Optional arguments:**
+
−
+
−        * ``template_name``: The full name of a template to use. This will
+
−          default to :file:`registration/password_change_done.html` if not
+
−          supplied.
+
−
+
−.. function:: views.password_reset(request[, is_admin_site, template_name, email_template_name, password_reset_form, token_generator, post_reset_redirect])
+
−
+
−    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 e-mail address.
+
−
+
−    **Optional arguments:**
+
−
+
−        * ``template_name``: The full name of a template to use for
+
−          displaying the password reset form. This will default to
+
−          :file:`registration/password_reset_form.html` if not supplied.
+
−
+
−        * ``email_template_name``: The full name of a template to use for
+
−          generating the e-mail with the new password. This will default to
+
−          :file:`registration/password_reset_email.html` if not supplied.
+
−
+
−        * ``password_reset_form``: Form that will be used to set the password.
+
−          Defaults to :class:`~django.contrib.auth.forms.PasswordResetForm`.
+
−
+
−        * ``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_redirect``: The URL to redirect to after a successful
+
−          password change.
+
−
+
−    **Template context:**
+
−
+
−        * ``form``: The form for resetting the user's password.
+
−
+
−.. function:: views.password_reset_done(request[, template_name])
+
−
+
−    The page shown after a user has reset their password.
+
−
+
−    **Optional arguments:**
+
−
+
−        * ``template_name``: The full name of a template to use. This will
+
−          default to :file:`registration/password_reset_done.html` if not
+
−          supplied.
+
−
+
−.. function:: views.redirect_to_login(next[, login_url, redirect_field_name])
+
−
+
−    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. This will
+
−          default to :setting:`settings.LOGIN_URL <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.
+
−
+
−.. function:: password_reset_confirm(request[, uidb36, token, template_name, token_generator, set_password_form, post_reset_redirect])
+
−
+
−    Presents a form for entering a new password.
+
−
+
−    **Optional arguments:**
+
−
+
−        * ``uidb36``: The user's id encoded in base 36. This will default to
+
−          ``None``.
+
−        * ``token``: Token to check that the password is valid. This will default to ``None``.
+
−        * ``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``.
+
−        * ``set_password_form``: Form that will be used to set the password.
+
−          This will default to ``SetPasswordForm``.
+
−        * ``post_reset_redirect``: URL to redirect after the password reset
+
−          done. This will default to ``None``.
+
−
+
−.. function:: password_reset_complete(request[,template_name])
+
−
+
−   Presents a view which informs the user that the password has been
+
−   successfully changed.
+
−
+
−   **Optional arguments:**
+
−
+
−       * ``template_name``: The full name of a template to display the view.
+
−         This will default to :file:`registration/password_reset_complete.html`.
+
−
+
−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`:
+
−
+
−.. class:: AdminPasswordChangeForm
+
−
+
−    A form used in the admin interface to change a user's password.
+
−
+
−.. class:: AuthenticationForm
+
−
+
−    A form for logging a user in.
+
−
+
−.. class:: PasswordChangeForm
+
−
+
−    A form for allowing a user to change their password.
+
−
+
−.. class:: PasswordResetForm
+
−
+
−    A form for generating and e-mailing a one-time use link to reset a
+
−    user's password.
+
−
+
−.. class:: SetPasswordForm
+
−
+
−    A form that lets a user change his/her 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 form for creating a new user.
+
−
+
−Limiting access to logged-in users that pass a test
+
−---------------------------------------------------
+
−
+
−.. currentmodule:: django.contrib.auth
+
−
+
−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
+
−<django.http.HttpRequest.user>` in the view directly. For example, this view
+
−checks to make sure the user is logged in and has the permission
+
−``polls.can_vote``::
+
−
+
−    def my_view(request):
+
−        if not request.user.has_perm('polls.can_vote'):
+
−            return HttpResponse("You can't vote in this poll.")
+
−        # ...
+
−
+
−.. function:: decorators.user_passes_test()
+
−
+
−    As a shortcut, you can use the convenient ``user_passes_test`` decorator::
+
−
+
−        from django.contrib.auth.decorators import user_passes_test
+
−
+
−        @user_passes_test(lambda u: u.has_perm('polls.can_vote'))
+
−        def my_view(request):
+
−            ...
+
−
+
−    We're using this particular test as a relatively simple example. However,
+
−    if you just want to test whether a permission is available to a user, you
+
−    can use the :func:`~django.contrib.auth.decorators.permission_required()`
+
−    decorator, described later in this document.
+
−
+
−    :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 an
+
−    optional ``login_url`` argument, which lets you specify the URL for your
+
−    login page (:setting:`settings.LOGIN_URL <LOGIN_URL>` by default).
+
−
+
−    For example::
+
−
+
−        from django.contrib.auth.decorators import user_passes_test
+
−
+
−        @user_passes_test(lambda u: u.has_perm('polls.can_vote'), login_url='/login/')
+
−        def my_view(request):
+
−            ...
+
−
+
−The permission_required decorator
+
−~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
−
+
−.. function:: decorators.permission_required()
+
−
+
−    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.
+
−    Using this decorator, the earlier example can be written as::
+
−
+
−        from django.contrib.auth.decorators import permission_required
+
−
+
−        @permission_required('polls.can_vote')
+
−        def my_view(request):
+
−            ...
+
−
+
−    As for the :meth:`User.has_perm` method, permission names take the form
+
−    ``"<app label>.<permission codename>"`` (i.e. ``polls.can_vote`` for a
+
−    permission on a model in the ``polls`` application).
+
−
+
−    Note that :func:`~django.contrib.auth.decorators.permission_required()`
+
−    also takes an optional ``login_url`` parameter. Example::
+
−
+
−        from django.contrib.auth.decorators import permission_required
+
−
+
−        @permission_required('polls.can_vote', login_url='/loginpage/')
+
−        def my_view(request):
+
−            ...
+
−
+
−    As in the :func:`~decorators.login_required` decorator, ``login_url``
+
−    defaults to :setting:`settings.LOGIN_URL <LOGIN_URL>`.
+
−
+
−Limiting access to generic views
+
−--------------------------------
+
−
+
−To limit access to a :doc:`generic view </ref/generic-views>`, write a thin
+
−wrapper around the view, and point your URLconf to your wrapper instead of the
+
−generic view itself. For example::
+
−
+
−    from django.views.generic.date_based import object_detail
+
−
+
−    @login_required
+
−    def limited_object_detail(*args, **kwargs):
+
−        return object_detail(*args, **kwargs)
+
−
+
−.. _permissions:
+
−
+
−Permissions
+
−===========
+
−
+
−Django comes with a simple permissions system. It provides a way to assign
+
−permissions to specific users and groups of users.
+
−
+
−It's used by the Django admin site, but you're welcome to use it in your own
+
−code.
+
−
+
−The Django admin site uses permissions as follows:
+
−
+
−    * Access to view the "add" form and add an object is limited to users with
+
−      the "add" permission for that type of object.
+
−    * Access to view the change list, view the "change" form and change an
+
−      object is limited to users with the "change" permission for that type of
+
−      object.
+
−    * Access to delete an object is limited to users with the "delete"
+
−      permission for that type of object.
+
−
+
−Permissions are set globally per type of object, not per specific object
+
−instance. For example, it's possible to say "Mary may change news stories," but
+
−it's not currently possible to say "Mary may change news stories, but only the
+
−ones she created herself" or "Mary may only change news stories that have a
+
−certain status, publication date or ID." The latter functionality is something
+
−Django developers are currently discussing.
+
−
+
−Default permissions
+
−-------------------
+
−
+
−When ``django.contrib.auth`` is listed in your :setting:`INSTALLED_APPS`
+
−setting, it will ensure that three default permissions -- add, change and
+
−delete -- are created for each Django model defined in one of your installed
+
−applications.
+
−
+
−These permissions will be created when you run :djadmin:`manage.py syncdb
+
−<syncdb>`; the first time you run ``syncdb`` after adding
+
−``django.contrib.auth`` to :setting:`INSTALLED_APPS`, the default permissions
+
−will be created for all previously-installed models, as well as for any new
+
−models being installed at that time. Afterward, it will create default
+
−permissions for new models each time you run :djadmin:`manage.py syncdb
+
−<syncdb>`.
+
−
+
−Assuming you have an application with an
+
−:attr:`~django.db.models.Options.app_label` ``foo`` and a model named ``Bar``,
+
−to test for basic permissions you should use:
+
−
+
−    * add: ``user.has_perm('foo.add_bar')``
+
−    * change: ``user.has_perm('foo.change_bar')``
+
−    * delete: ``user.has_perm('foo.delete_bar')``
+
−
+
−.. _custom-permissions:
+
−
+
−Custom permissions
+
−------------------
+
−
+
−To create custom permissions for a given model object, use the ``permissions``
+
−:ref:`model Meta attribute <meta-options>`.
+
−
+
−This example Task model creates three custom permissions, i.e., actions users
+
−can or cannot do with Task instances, specific to your appication::
+
−
+
−    class Task(models.Model):
+
−        ...
+
−        class Meta:
+
−            permissions = (
+
−                ("can_view", "Can see available tasks"),
+
−                ("can_change_status", "Can change the status of tasks"),
+
−                ("can_close", "Can remove a task by setting its status as closed"),
+
−            )
+
−
+
−The only thing this does is create those extra permissions when you run
+
−:djadmin:`manage.py syncdb <syncdb>`. Your code is in charge of checking the
+
−value of these permissions when an user is trying to access the functionality
+
−provided by the application (viewing tasks, changing the status of tasks,
+
−closing tasks.)
+
−
+
−API reference
+
−-------------
+
−
+
−.. class:: models.Permission
+
−
+
−    Just like users, permissions are implemented in a Django model that lives
+
−    in `django/contrib/auth/models.py`_.
+
−
+
−.. _django/contrib/auth/models.py: http://code.djangoproject.com/browser/django/trunk/django/contrib/auth/models.py
+
−
+
−Fields
+
−~~~~~~
+
−
+
−:class:`~django.contrib.auth.models.Permission` objects have the following
+
−fields:
+
−
+
−.. attribute:: models.Permission.name
+
−
+
−    Required. 50 characters or fewer. Example: ``'Can vote'``.
+
−
+
−.. attribute:: models.Permission.content_type
+
−
+
−    Required. A reference to the ``django_content_type`` database table, which
+
−    contains a record for each installed Django model.
+
−
+
−.. attribute:: models.Permission.codename
+
−
+
−    Required. 100 characters or fewer. Example: ``'can_vote'``.
+
−
+
−Methods
+
−~~~~~~~
+
−
+
−:class:`~django.contrib.auth.models.Permission` objects have the standard
+
−data-access methods like any other :doc:`Django model </ref/models/instances>`.
+
−
+
−Authentication data in templates
+
−================================
+
−
+
−The currently logged-in user and his/her permissions are made available in the
+
−:doc:`template context </ref/templates/api>` when you use
+
−:class:`~django.template.context.RequestContext`.
+
−
+
−.. admonition:: Technicality
+
−
+
−   Technically, these variables are only made available in the template context
+
−   if you use :class:`~django.template.context.RequestContext` *and* your
+
−   :setting:`TEMPLATE_CONTEXT_PROCESSORS` setting contains
+
−   ``"django.contrib.auth.context_processors.auth"``, which is default. For
+
−   more, see the :ref:`RequestContext docs <subclassing-context-requestcontext>`.
+
−
+
−Users
+
−-----
+
−
+
−When rendering a template :class:`~django.template.context.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 %}
+
−        <p>Welcome, {{ user.username }}. Thanks for logging in.</p>
+
−    {% else %}
+
−        <p>Welcome, new user. Please log in.</p>
+
−    {% 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
+
−:class:`django.core.context_processors.PermWrapper`, which is a
+
−template-friendly proxy of permissions.
+
−
+
−In the ``{{ perms }}`` object, single-attribute lookup is a proxy to
+
−:meth:`User.has_module_perms <django.contrib.auth.models.User.has_module_perms>`.
+
−This example would display ``True`` if the logged-in user had any permissions
+
−in the ``foo`` app::
+
−
+
−    {{ perms.foo }}
+
−
+
−Two-level-attribute lookup is a proxy to
+
−:meth:`User.has_perm <django.contrib.auth.models.User.has_perm>`. This example
+
−would display ``True`` if the logged-in user had the permission
+
−``foo.can_vote``::
+
−
+
−    {{ perms.foo.can_vote }}
+
−
+
−Thus, you can check permissions in template ``{% if %}`` statements:
+
−
+
−.. code-block:: html+django
+
−
+
−    {% if perms.foo %}
+
−        <p>You have permission to do something in the foo app.</p>
+
−        {% if perms.foo.can_vote %}
+
−            <p>You can vote!</p>
+
−        {% endif %}
+
−        {% if perms.foo.can_drive %}
+
−            <p>You can drive!</p>
+
−        {% endif %}
+
−    {% else %}
+
−        <p>You don't have permission to do anything in the foo app.</p>
+
−    {% endif %}
+
−
+
−Groups
+
−======
+
−
+
−Groups are a generic way of categorizing users so you can apply permissions, or
+
−some other label, to those users. A user can belong to any number of groups.
+
−
+
−A user in a group automatically has the permissions granted to that group. For
+
−example, if the group ``Site editors`` has the permission
+
−``can_edit_home_page``, any user in that group will have that permission.
+
−
+
−Beyond permissions, groups are a convenient way to categorize users to give
+
−them some label, or extended functionality. For example, you could create a
+
−group ``'Special users'``, and you could write code that could, say, give them
+
−access to a members-only portion of your site, or send them members-only e-mail
+
−messages.
+
−
+
−Messages
+
−========
+
−
+
−.. deprecated:: 1.2
+
−   This functionality will be removed in Django 1.4.  You should use the
+
−   :doc:`messages framework </ref/contrib/messages>` for all new projects and
+
−   begin to update your existing code immediately.
+
−
+
−The message system is a lightweight way to queue messages for given users.
+
−
+
−A message is associated with a :class:`~django.contrib.auth.models.User`.
+
−There's no concept of expiration or timestamps.
+
−
+
−Messages are used by the Django admin after successful actions. For example,
+
−``"The poll Foo was created successfully."`` is a message.
+
−
+
−The API is simple:
+
−
+
−.. method:: models.User.message_set.create(message)
+
−
+
−    To create a new message, use
+
−    ``user_obj.message_set.create(message='message_text')``.
+
−
+
−    To retrieve/delete messages, use
+
−    :meth:`user_obj.get_and_delete_messages() <django.contrib.auth.models.User.get_and_delete_messages>`,
+
−    which returns a list of ``Message`` objects in the user's queue (if any)
+
−    and deletes the messages from the queue.
+
−
+
−In this example view, the system saves a message for the user after creating
+
−a playlist::
+
−
+
−    def create_playlist(request, songs):
+
−        # Create the playlist with the given songs.
+
−        # ...
+
−        request.user.message_set.create(message="Your playlist was added successfully.")
+
−        return render_to_response("playlists/create.html",
+
−            context_instance=RequestContext(request))
+
−
+
−When you use :class:`~django.template.context.RequestContext`, the currently
+
−logged-in user and his/her messages are made available in the
+
−:doc:`template context </ref/templates/api>` as the template variable
+
−``{{ messages }}``. Here's an example of template code that displays messages:
+
−
+
−.. code-block:: html+django
+
−
+
−    {% if messages %}
+
−    <ul>
+
−        {% for message in messages %}
+
−        <li>{{ message }}</li>
+
−        {% endfor %}
+
−    </ul>
+
−    {% endif %}
+
−
+
−.. versionchanged:: 1.2
+
−   The ``messages`` template variable uses a backwards compatible method in the
+
−   :doc:`messages framework </ref/contrib/messages>` to retrieve messages from
+
−   both the user ``Message`` model and from the new framework.  Unlike in
+
−   previous revisions, the messages will not be erased unless they are actually
+
−   displayed.
+
−
+
−Finally, note that this messages framework only works with users in the user
+
−database. To send messages to anonymous users, use the
+
−:doc:`messages framework </ref/contrib/messages>`.
+
−
+
−.. _authentication-backends:
+
−
+
−Other authentication sources
+
−============================
+
−
+
−The authentication that comes with Django is good enough for most common cases,
+
−but you may have the need to hook into another authentication source -- that
+
−is, another source of usernames and passwords or authentication methods.
+
−
+
−For example, your company may already have an LDAP setup that stores a username
+
−and password for every employee. It'd be a hassle for both the network
+
−administrator and the users themselves if users had separate accounts in LDAP
+
−and the Django-based applications.
+
−
+
−So, to handle situations like this, the Django authentication system lets you
+
−plug in other authentication sources. You can override Django's default
+
−database-based scheme, or you can use the default system in tandem with other
+
−systems.
+
−
+
−See the :doc:`authentication backend reference </ref/authbackends>`
+
−for information on the authentication backends included with Django.
+
−
+
−Specifying authentication backends
+
−----------------------------------
+
−
+
−Behind the scenes, Django maintains a list of "authentication backends" that it
+
−checks for authentication. When somebody calls
+
−:func:`django.contrib.auth.authenticate()` -- as described in :ref:`How to log
+
−a user in <how-to-log-a-user-in>` above -- Django tries authenticating across
+
−all of its authentication backends. If the first authentication method fails,
+
−Django tries the second one, and so on, until all backends have been attempted.
+
−
+
−The list of authentication backends to use is specified in the
+
−:setting:`AUTHENTICATION_BACKENDS` setting. This should be a tuple of Python
+
−path names that point to Python classes that know how to authenticate. These
+
−classes can be anywhere on your Python path.
+
−
+
−By default, :setting:`AUTHENTICATION_BACKENDS` is set to::
+
−
+
−    ('django.contrib.auth.backends.ModelBackend',)
+
−
+
−That's the basic authentication scheme that checks the Django users database.
+
−
+
−The order of :setting:`AUTHENTICATION_BACKENDS` matters, so if the same
+
−username and password is valid in multiple backends, Django will stop
+
−processing at the first positive match.
+
−
+
−.. note::
+
−
+
−    Once a user has authenticated, Django stores which backend was used to
+
−    authenticate the user in the user's session, and re-uses the same backend
+
−    for subsequent authentication attempts for that user. This effectively means
+
−    that authentication sources are cached, so if you change
+
−    :setting:`AUTHENTICATION_BACKENDS`, you'll need to clear out session data if
+
−    you need to force users to re-authenticate using different methods. A simple
+
−    way to do that is simply to execute ``Session.objects.all().delete()``.
+
−
+
−Writing an authentication backend
+
−---------------------------------
+
−
+
−An authentication backend is a class that implements two methods:
+
−``get_user(user_id)`` and ``authenticate(**credentials)``.
+
−
+
−The ``get_user`` method takes a ``user_id`` -- which could be a username,
+
−database ID or whatever -- and returns a ``User`` object.
+
−
+
−The ``authenticate`` method takes credentials as keyword arguments. Most of
+
−the time, it'll just look like this::
+
−
+
−    class MyBackend:
+
−        def authenticate(self, username=None, password=None):
+
−            # Check the username/password and return a User.
+
−
+
−But it could also authenticate a token, like so::
+
−
+
−    class MyBackend:
+
−        def authenticate(self, token=None):
+
−            # Check the token and return a User.
+
−
+
−Either way, ``authenticate`` should check the credentials it gets, and it
+
−should return a ``User`` object that matches those credentials, if the
+
−credentials are valid. If they're not valid, it should return ``None``.
+
−
+
−The Django admin system is tightly coupled to the Django ``User`` object
+
−described at the beginning of this document. For now, the best way to deal with
+
−this is to create a Django ``User`` object for each user that exists for your
+
−backend (e.g., in your LDAP directory, your external SQL database, etc.) You
+
−can either write a script to do this in advance, or your ``authenticate``
+
−method can do it the first time a user logs in.
+
−
+
−Here's an example backend that authenticates against a username and password
+
−variable defined in your ``settings.py`` file and creates a Django ``User``
+
−object the first time a user authenticates::
+
−
+
−    from django.conf import settings
+
−    from django.contrib.auth.models import User, check_password
+
−
+
−    class SettingsBackend:
+
−        """
+
−        Authenticate against the settings ADMIN_LOGIN and ADMIN_PASSWORD.
+
−
+
−        Use the login name, and a hash of the password. For example:
+
−
+
−        ADMIN_LOGIN = 'admin'
+
−        ADMIN_PASSWORD = 'sha1$4e987$afbcf42e21bd417fb71db8c66b321e9fc33051de'
+
−        """
+
−        def authenticate(self, username=None, password=None):
+
−            login_valid = (settings.ADMIN_LOGIN == username)
+
−            pwd_valid = check_password(password, settings.ADMIN_PASSWORD)
+
−            if login_valid and pwd_valid:
+
−                try:
+
−                    user = User.objects.get(username=username)
+
−                except User.DoesNotExist:
+
−                    # Create a new user. Note that we can set password
+
−                    # to anything, because it won't be checked; the password
+
−                    # from settings.py will.
+
−                    user = User(username=username, password='get from settings.py')
+
−                    user.is_staff = True
+
−                    user.is_superuser = True
+
−                    user.save()
+
−                return user
+
−            return None
+
−
+
−        def get_user(self, user_id):
+
−            try:
+
−                return User.objects.get(pk=user_id)
+
−            except User.DoesNotExist:
+
−                return None
+
−
+
−Handling authorization in custom backends
+
−-----------------------------------------
+
−
+
−Custom auth backends can provide their own permissions.
+
−
+
−The user model will delegate permission lookup functions
+
−(:meth:`~django.contrib.auth.models.User.get_group_permissions()`,
+
−:meth:`~django.contrib.auth.models.User.get_all_permissions()`,
+
−:meth:`~django.contrib.auth.models.User.has_perm()`, and
+
−:meth:`~django.contrib.auth.models.User.has_module_perms()`) to any
+
−authentication backend that implements these functions.
+
−
+
−The permissions given to the user will be the superset of all permissions
+
−returned by all backends. That is, Django grants a permission to a user that
+
−any one backend grants.
+
−
+
−The simple backend above could implement permissions for the magic admin
+
−fairly simply::
+
−
+
−    class SettingsBackend:
+
−
+
−        # ...
+
−
+
−        def has_perm(self, user_obj, perm):
+
−            if user_obj.username == settings.ADMIN_LOGIN:
+
−                return True
+
−            else:
+
−                return False
+
−
+
−This gives full permissions to the user granted access in the above example.
+
−Notice that the backend auth functions all take the user object as an argument,
+
−and they also accept the same arguments given to the associated
+
−:class:`django.contrib.auth.models.User` functions.
+
−
+
−A full authorization implementation can be found in
+
−`django/contrib/auth/backends.py`_, which is the default backend and queries
+
−the ``auth_permission`` table most of the time.
+
−
+
−.. _django/contrib/auth/backends.py: http://code.djangoproject.com/browser/django/trunk/django/contrib/auth/backends.py
+
−
+
−Authorization for anonymous users
+
−~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
−
+
−.. versionchanged:: 1.2
+
−
+
−An anonymous user is one that is not authenticated i.e. they have provided no
+
−valid authentication details. However, that does not necessarily mean they are
+
−not authorized to do anything. At the most basic level, most Web sites
+
−authorize anonymous users to browse most of the site, and many allow anonymous
+
−posting of comments etc.
+
−
+
−Django's permission framework does not have a place to store permissions for
+
−anonymous users. However, it has a foundation that allows custom authentication
+
−backends to specify authorization for anonymous users. This is especially useful
+
−for the authors of re-usable apps, who can delegate all questions of authorization
+
−to the auth backend, rather than needing settings, for example, to control
+
−anonymous access.
+
−
+
−To enable this in your own backend, you must set the class attribute
+
−``supports_anonymous_user`` to ``True``. (This precaution is to maintain
+
−compatibility with backends that assume that all user objects are actual
+
−instances of the :class:`django.contrib.auth.models.User` class). With this
+
−in place, :class:`django.contrib.auth.models.AnonymousUser` will delegate all
+
−the relevant permission methods to the authentication backends.
+
−
+
−A nonexistent ``supports_anonymous_user`` attribute will raise a hidden
+
−``PendingDeprecationWarning`` if used in Django 1.2. In Django 1.3, this
+
−warning will be upgraded to a ``DeprecationWarning``, which will be displayed
+
−loudly. Additionally ``supports_anonymous_user`` will be set to ``False``.
+
−Django 1.4 will assume that every backend supports anonymous users being
+
−passed to the authorization methods.
+
−
+
−Handling object permissions
+
−---------------------------
+
−
+
−Django's permission framework has a foundation for object permissions, though
+
−there is no implementation for it in the core. That means that checking for
+
−object permissions will always return ``False`` or an empty list (depending on
+
−the check performed).
+
−
+
−To enable object permissions in your own
+
−:doc:`authentication backend </ref/authbackends>` you'll just have
+
−to allow passing an ``obj`` parameter to the permission methods and set the
+
−``supports_object_permissions`` class attribute to ``True``.
+
−
+
−A nonexistent ``supports_object_permissions`` will raise a hidden
+
−``PendingDeprecationWarning`` if used in Django 1.2. In Django 1.3, this
+
−warning will be upgraded to a ``DeprecationWarning``, which will be displayed
+
−loudly. Additionally ``supports_object_permissions`` will be set to ``False``.
+
−Django 1.4 will assume that every backend supports object permissions and
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−won't check for the existence of ``supports_object_permissions``, which
+
−means not supporting ``obj`` as a parameter will raise a ``TypeError``.