1499 lines
56 KiB
Plaintext
1499 lines
56 KiB
Plaintext
.. _topics-auth:
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=============================
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User authentication in Django
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=============================
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.. module:: django.contrib.auth
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:synopsis: Django's authentication framework.
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Django comes with a user authentication system. It handles user accounts,
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groups, permissions and cookie-based user sessions. This document explains how
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things work.
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Overview
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========
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The auth system consists of:
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* Users
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* Permissions: Binary (yes/no) flags designating whether a user may perform
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a certain task.
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* Groups: A generic way of applying labels and permissions to more than one
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user.
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* Messages: A simple way to queue messages for given users.
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Installation
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============
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Authentication support is bundled as a Django application in
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``django.contrib.auth``. To install it, do the following:
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1. Put ``'django.contrib.auth'`` in your :setting:`INSTALLED_APPS` setting.
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2. Run the command ``manage.py syncdb``.
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Note that the default :file:`settings.py` file created by
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:djadmin:`django-admin.py startproject` includes ``'django.contrib.auth'`` in
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:setting:`INSTALLED_APPS` for convenience. If your :setting:`INSTALLED_APPS`
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already contains ``'django.contrib.auth'``, feel free to run
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:djadmin:`manage.py syncdb` again; you can run that command as many times as
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you'd like, and each time it'll only install what's needed.
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The :djadmin:`syncdb` command creates the necessary database tables, creates
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permission objects for all installed apps that need 'em, and prompts you to
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create a superuser account the first time you run it.
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Once you've taken those steps, that's it.
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Users
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=====
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.. class:: models.User
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API reference
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-------------
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Fields
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~~~~~~
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.. class:: models.User
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:class:`~django.contrib.auth.models.User` objects have the following
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fields:
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.. attribute:: models.User.username
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Required. 30 characters or fewer. Alphanumeric characters only
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(letters, digits and underscores).
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.. attribute:: models.User.first_name
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Optional. 30 characters or fewer.
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.. attribute:: models.User.last_name
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Optional. 30 characters or fewer.
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.. attribute:: models.User.email
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Optional. E-mail address.
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.. attribute:: models.User.password
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Required. A hash of, and metadata about, the password. (Django doesn't
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store the raw password.) Raw passwords can be arbitrarily long and can
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contain any character. See the "Passwords" section below.
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.. attribute:: models.User.is_staff
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Boolean. Designates whether this user can access the admin site.
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.. attribute:: models.User.is_active
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Boolean. Designates whether this user account should be considered
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active. Set this flag to ``False`` instead of deleting accounts.
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This doesn't control whether or not the user can log in. Nothing in the
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authentication path checks the ``is_active`` flag, so if you want to
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reject a login based on ``is_active`` being ``False``, it is up to you
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to check that in your own login view. However, permission checking
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using the methods like :meth:`~models.User.has_perm` does check this
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flag and will always return ``False`` for inactive users.
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.. attribute:: models.User.is_superuser
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Boolean. Designates that this user has all permissions without
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explicitly assigning them.
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.. attribute:: models.User.last_login
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A datetime of the user's last login. Is set to the current date/time by
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default.
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.. attribute:: models.User.date_joined
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A datetime designating when the account was created. Is set to the
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current date/time by default when the account is created.
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Methods
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~~~~~~~
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.. class:: models.User
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:class:`~django.contrib.auth.models.User` objects have two many-to-many
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fields: models.User. ``groups`` and ``user_permissions``.
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:class:`~django.contrib.auth.models.User` objects can access their related
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objects in the same way as any other :ref:`Django model
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<topics-db-models>`:
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.. code-block:: python
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myuser.groups = [group_list]
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myuser.groups.add(group, group, ...)
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myuser.groups.remove(group, group, ...)
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myuser.groups.clear()
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myuser.user_permissions = [permission_list]
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myuser.user_permissions.add(permission, permission, ...)
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myuser.user_permissions.remove(permission, permission, ...)
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myuser.user_permissions.clear()
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In addition to those automatic API methods,
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:class:`~django.contrib.auth.models.User` objects have the following custom
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methods:
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.. method:: models.User.is_anonymous()
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Always returns ``False``. This is a way of differentiating
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:class:`~django.contrib.auth.models.User` and
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:class:`~django.contrib.auth.models.AnonymousUser` objects.
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Generally, you should prefer using
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:meth:`~django.contrib.auth.models.User.is_authenticated()` to this
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method.
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.. method:: models.User.is_authenticated()
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Always returns ``True``. This is a way to tell if the user has been
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authenticated. This does not imply any permissions, and doesn't check
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if the user is active - it only indicates that the user has provided a
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valid username and password.
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.. method:: models.User.get_full_name()
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Returns the :attr:`~django.contrib.auth.models.User.first_name` plus
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the :attr:`~django.contrib.auth.models.User.last_name`, with a space in
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between.
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.. method:: models.User.set_password(raw_password)
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Sets the user's password to the given raw string, taking care of the
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password hashing. Doesn't save the
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:class:`~django.contrib.auth.models.User` object.
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.. method:: models.User.check_password(raw_password)
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Returns ``True`` if the given raw string is the correct password for
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the user. (This takes care of the password hashing in making the
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comparison.)
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.. method:: models.User.set_unusable_password()
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.. versionadded:: 1.0
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Marks the user as having no password set. This isn't the same as
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having a blank string for a password.
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:meth:`~django.contrib.auth.models.User.check_password()` for this user
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will never return ``True``. Doesn't save the
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:class:`~django.contrib.auth.models.User` object.
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You may need this if authentication for your application takes place
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against an existing external source such as an LDAP directory.
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.. method:: models.User.has_usable_password()
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.. versionadded:: 1.0
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Returns ``False`` if
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:meth:`~django.contrib.auth.models.User.set_unusable_password()` has
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been called for this user.
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.. method:: models.User.get_group_permissions()
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Returns a list of permission strings that the user has, through his/her
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groups.
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.. method:: models.User.get_all_permissions()
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Returns a list of permission strings that the user has, both through
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group and user permissions.
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.. method:: models.User.has_perm(perm)
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Returns ``True`` if the user has the specified permission, where perm is
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in the format ``"<application name>.<lowercased model name>"``. If the
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user is inactive, this method will always return ``False``.
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.. method:: models.User.has_perms(perm_list)
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Returns ``True`` if the user has each of the specified permissions,
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where each perm is in the format ``"package.codename"``. If the user is
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inactive, this method will always return ``False``.
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.. method:: models.User.has_module_perms(package_name)
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Returns ``True`` if the user has any permissions in the given package
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(the Django app label). If the user is inactive, this method will
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always return ``False``.
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.. method:: models.User.get_and_delete_messages()
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Returns a list of :class:`~django.contrib.auth.models.Message` objects
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in the user's queue and deletes the messages from the queue.
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.. method:: models.User.email_user(subject, message, from_email=None)
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Sends an e-mail to the user. If
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:attr:`~django.contrib.auth.models.User.from_email` is ``None``, Django
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uses the :setting:`DEFAULT_FROM_EMAIL`.
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.. method:: models.User.get_profile()
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Returns a site-specific profile for this user. Raises
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:exc:`django.contrib.auth.models.SiteProfileNotAvailable` if the
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current site doesn't allow profiles. For information on how to define a
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site-specific user profile, see the section on `storing additional user
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information`_ below.
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.. _storing additional user information: #storing-additional-information-about-users
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Manager functions
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~~~~~~~~~~~~~~~~~
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.. class:: models.UserManager
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The :class:`~django.contrib.auth.models.User` model has a custom manager
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that has the following helper functions:
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.. method:: models.UserManager.create_user(username, email, password=None)
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Creates, saves and returns a :class:`~django.contrib.auth.models.User`.
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The :attr:`~django.contrib.auth.models.User.username`,
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:attr:`~django.contrib.auth.models.User.email` and
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:attr:`~django.contrib.auth.models.User.password` are set as given, and
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the :class:`~django.contrib.auth.models.User` gets ``is_active=True``.
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If no password is provided,
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:meth:`~django.contrib.auth.models.User.set_unusable_password()` will
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be called.
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See `Creating users`_ for example usage.
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.. method:: models.UserManager.make_random_password(length=10, allowed_chars='abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789')
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Returns a random password with the given length and given string of
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allowed characters. (Note that the default value of ``allowed_chars``
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doesn't contain letters that can cause user confusion, including:
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* ``i``, ``l``, ``I``, and ``1`` (lowercase letter i, lowercase
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letter L, uppercase letter i, and the number one)
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* ``o``, ``O``, and ``0`` (uppercase letter o, lowercase letter o,
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and zero)
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Basic usage
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-----------
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.. _topics-auth-creating-users:
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Creating users
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~~~~~~~~~~~~~~
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The most basic way to create users is to use the
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:meth:`~django.contrib.auth.models.UserManager.create_user` helper function
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that comes with Django::
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>>> from django.contrib.auth.models import User
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>>> user = User.objects.create_user('john', 'lennon@thebeatles.com', 'johnpassword')
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# At this point, user is a User object that has already been saved
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# to the database. You can continue to change its attributes
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# if you want to change other fields.
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>>> user.is_staff = True
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>>> user.save()
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You can also create users using the Django admin site. Assuming you've enabled
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the admin site and hooked it to the URL ``/admin/``, the "Add user" page is at
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``/admin/auth/user/add/``. You should also see a link to "Users" in the "Auth"
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section of the main admin index page. The "Add user" admin page is different
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than standard admin pages in that it requires you to choose a username and
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password before allowing you to edit the rest of the user's fields.
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Also note: if you want your own user account to be able to create users using
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the Django admin site, you'll need to give yourself permission to add users
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*and* change users (i.e., the "Add user" and "Change user" permissions). If
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your account has permission to add users but not to change them, you won't be
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able to add users. Why? Because if you have permission to add users, you have
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the power to create superusers, which can then, in turn, change other users. So
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Django requires add *and* change permissions as a slight security measure.
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Changing passwords
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~~~~~~~~~~~~~~~~~~
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Change a password with :meth:`~django.contrib.auth.models.User.set_password()`:
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.. code-block:: python
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>>> from django.contrib.auth.models import User
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>>> u = User.objects.get(username__exact='john')
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>>> u.set_password('new password')
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>>> u.save()
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Don't set the :attr:`~django.contrib.auth.models.User.password` attribute
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directly unless you know what you're doing. This is explained in the next
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section.
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Passwords
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---------
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The :attr:`~django.contrib.auth.models.User.password` attribute of a
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:class:`~django.contrib.auth.models.User` object is a string in this format::
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hashtype$salt$hash
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That's hashtype, salt and hash, separated by the dollar-sign character.
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Hashtype is either ``sha1`` (default), ``md5`` or ``crypt`` -- the algorithm
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used to perform a one-way hash of the password. Salt is a random string used
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to salt the raw password to create the hash. Note that the ``crypt`` method is
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only supported on platforms that have the standard Python ``crypt`` module
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available.
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.. versionadded:: 1.0
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Support for the ``crypt`` module is new in Django 1.0.
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For example::
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sha1$a1976$a36cc8cbf81742a8fb52e221aaeab48ed7f58ab4
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The :meth:`~django.contrib.auth.models.User.set_password` and
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:meth:`~django.contrib.auth.models.User.check_password` functions handle the
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setting and checking of these values behind the scenes.
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Previous Django versions, such as 0.90, used simple MD5 hashes without password
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salts. For backwards compatibility, those are still supported; they'll be
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converted automatically to the new style the first time
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:meth:`~django.contrib.auth.models.User.check_password()` works correctly for
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a given user.
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Anonymous users
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---------------
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.. class:: models.AnonymousUser
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:class:`django.contrib.auth.models.AnonymousUser` is a class that
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implements the :class:`django.contrib.auth.models.User` interface, with
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these differences:
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* :attr:`~django.contrib.auth.models.User.id` is always ``None``.
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* :attr:`~django.contrib.auth.models.User.is_staff` and
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:attr:`~django.contrib.auth.models.User.is_superuser` are always
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``False``.
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* :attr:`~django.contrib.auth.models.User.is_active` is always ``False``.
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* :attr:`~django.contrib.auth.models.User.groups` and
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:attr:`~django.contrib.auth.models.User.user_permissions` are always
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empty.
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* :meth:`~django.contrib.auth.models.User.is_anonymous()` returns ``True``
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instead of ``False``.
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* :meth:`~django.contrib.auth.models.User.is_authenticated()` returns
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``False`` instead of ``True``.
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* :meth:`~django.contrib.auth.models.User.has_perm()` always returns
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``False``.
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* :meth:`~django.contrib.auth.models.User.set_password()`,
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:meth:`~django.contrib.auth.models.User.check_password()`,
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:meth:`~django.contrib.auth.models.User.save()`,
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:meth:`~django.contrib.auth.models.User.delete()`,
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:meth:`~django.contrib.auth.models.User.set_groups()` and
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:meth:`~django.contrib.auth.models.User.set_permissions()` raise
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:exc:`NotImplementedError`.
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In practice, you probably won't need to use
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:class:`~django.contrib.auth.models.AnonymousUser` objects on your own, but
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they're used by Web requests, as explained in the next section.
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.. _topics-auth-creating-superusers:
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Creating superusers
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-------------------
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.. versionadded:: 1.0
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The ``manage.py createsuperuser`` command is new.
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:djadmin:`manage.py syncdb <syncdb>` prompts you to create a superuser the
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first time you run it after adding ``'django.contrib.auth'`` to your
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:setting:`INSTALLED_APPS`. If you need to create a superuser at a later date,
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you can use a command line utility::
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manage.py createsuperuser --username=joe --email=joe@example.com
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You will be prompted for a password. After you enter one, the user will be
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created immediately. If you leave off the :djadminopt:`--username` or the
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:djadminopt:`--email` options, it will prompt you for those values.
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If you're using an older release of Django, the old way of creating a superuser
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on the command line still works::
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python /path/to/django/contrib/auth/create_superuser.py
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...where :file:`/path/to` is the path to the Django codebase on your
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filesystem. The ``manage.py`` command is preferred because it figures out the
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correct path and environment for you.
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.. _auth-profiles:
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Storing additional information about users
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------------------------------------------
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If you'd like to store additional information related to your users, Django
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provides a method to specify a site-specific related model -- termed a "user
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profile" -- for this purpose.
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To make use of this feature, define a model with fields for the additional
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information you'd like to store, or additional methods you'd like to have
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available, and also add a :class:`~django.db.models.Field.ForeignKey` from your
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model to the :class:`~django.contrib.auth.models.User` model, specified with
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``unique=True`` to ensure only one instance of your model can be created for
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each :class:`~django.contrib.auth.models.User`.
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To indicate that this model is the user profile model for a given site, fill in
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the setting :setting:`AUTH_PROFILE_MODULE` with a string consisting of the
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following items, separated by a dot:
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1. The name of the application (case sensitive) in which the user
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profile model is defined (in other words, the
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name which was passed to :djadmin:`manage.py startapp <startapp>` to create
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the application).
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2. The name of the model (not case sensitive) class.
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For example, if the profile model was a class named ``UserProfile`` and was
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defined inside an application named ``accounts``, the appropriate setting would
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be::
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AUTH_PROFILE_MODULE = 'accounts.UserProfile'
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When a user profile model has been defined and specified in this manner, each
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:class:`~django.contrib.auth.models.User` object will have a method --
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:class:`~django.contrib.auth.models.User.get_profile()` -- which returns the
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instance of the user profile model associated with that
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:class:`~django.contrib.auth.models.User`.
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The method :class:`~django.contrib.auth.models.User.get_profile()`
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does not create the profile, if it does not exist. You need to
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register a handler for the signal
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:attr:`django.db.models.signals.post_save` on the User model, and, in
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the handler, if created=True, create the associated user profile.
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For more information, see `Chapter 12 of the Django book`_.
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.. _Chapter 12 of the Django book: http://www.djangobook.com/en/1.0/chapter12/#cn222
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Authentication in Web requests
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==============================
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Until now, this document has dealt with the low-level APIs for manipulating
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authentication-related objects. On a higher level, Django can hook this
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authentication framework into its system of
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:class:`request objects <django.http.HttpRequest>`.
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First, install the
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:class:`~django.contrib.sessions.middleware.SessionMiddleware` and
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:class:`~django.contrib.auth.middleware.AuthenticationMiddleware`
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middlewares by adding them to your :setting:`MIDDLEWARE_CLASSES` setting. See
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the :ref:`session documentation <topics-http-sessions>` for more information.
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Once you have those middlewares installed, you'll be able to access
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:attr:`request.user <django.http.HttpRequest.user>` in views.
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|
: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.
|
|
|
|
.. _howtologauserin:
|
|
|
|
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()
|
|
|
|
As a shortcut, you can use the convenient
|
|
:func:`~django.contrib.auth.decorators.login_required` decorator::
|
|
|
|
from django.contrib.auth.decorators import login_required
|
|
|
|
def my_view(request):
|
|
# ...
|
|
my_view = login_required(my_view)
|
|
|
|
Here's an equivalent example, using the more compact decorator syntax
|
|
introduced in Python 2.4::
|
|
|
|
from django.contrib.auth.decorators import login_required
|
|
|
|
@login_required
|
|
def my_view(request):
|
|
# ...
|
|
|
|
:func:`~django.contrib.auth.decorators.login_required` also takes an
|
|
optional ``redirect_field_name`` parameter. Example::
|
|
|
|
from django.contrib.auth.decorators import login_required
|
|
|
|
def my_view(request):
|
|
# ...
|
|
my_view = login_required(redirect_field_name='redirect_to')(my_view)
|
|
|
|
Again, an equivalent example of the more compact decorator syntax
|
|
introduced in Python 2.4::
|
|
|
|
from django.contrib.auth.decorators import login_required
|
|
|
|
@login_required(redirect_field_name='redirect_to')
|
|
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>` (``/accounts/login/`` by
|
|
default), passing the current absolute URL in the query string as
|
|
``next`` or the value of ``redirect_field_name``. For 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.
|
|
|
|
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])
|
|
|
|
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 :ref:`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 :ref:`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
|
|
|
|
{% 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 %}">
|
|
<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 %}
|
|
|
|
.. _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])
|
|
|
|
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.
|
|
|
|
**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, and sends them the new password
|
|
in an e-mail.
|
|
|
|
**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 ``SetPasswordForm``.
|
|
|
|
* ``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 resetting a user's password and e-mailing the new password to
|
|
them.
|
|
|
|
.. 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.is_authenticated() and 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
|
|
|
|
def my_view(request):
|
|
# ...
|
|
my_view = user_passes_test(lambda u: u.has_perm('polls.can_vote'))(my_view)
|
|
|
|
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.
|
|
|
|
Here's the same thing, using Python 2.4's decorator syntax::
|
|
|
|
from django.contrib.auth.decorators import user_passes_test
|
|
|
|
@user_passes_test(lambda u: u.has_perm('polls.can_vote'))
|
|
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 an
|
|
optional ``login_url`` argument, which lets you specify the URL for your
|
|
login page (:setting:`settings.LOGIN_URL <LOGIN_URL>` by default).
|
|
|
|
Example in Python 2.3 syntax::
|
|
|
|
from django.contrib.auth.decorators import user_passes_test
|
|
|
|
def my_view(request):
|
|
# ...
|
|
my_view = user_passes_test(lambda u: u.has_perm('polls.can_vote'), login_url='/login/')(my_view)
|
|
|
|
Example in Python 2.4 syntax::
|
|
|
|
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
|
|
|
|
def my_view(request):
|
|
# ...
|
|
my_view = permission_required('polls.can_vote')(my_view)
|
|
|
|
As for the :meth:`User.has_perm` method, permission names take the form
|
|
``"<application name>.<lowercased model name>"`` (i.e. ``polls.choice`` for
|
|
a ``Choice`` 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
|
|
|
|
def my_view(request):
|
|
# ...
|
|
my_view = permission_required('polls.can_vote', login_url='/loginpage/')(my_view)
|
|
|
|
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 :ref:`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
|
|
===========
|
|
|
|
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>`.
|
|
|
|
.. _custom-permissions:
|
|
|
|
Custom permissions
|
|
------------------
|
|
|
|
To create custom permissions for a given model object, use the ``permissions``
|
|
:ref:`model Meta attribute <meta-options>`.
|
|
|
|
This example model creates three custom permissions::
|
|
|
|
class USCitizen(models.Model):
|
|
# ...
|
|
class Meta:
|
|
permissions = (
|
|
("can_drive", "Can drive"),
|
|
("can_vote", "Can vote in elections"),
|
|
("can_drink", "Can drink alcohol"),
|
|
)
|
|
|
|
The only thing this does is create those extra permissions when you run
|
|
:djadmin:`manage.py syncdb <syncdb>`.
|
|
|
|
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 :ref:`Django model <ref-models-instances>`.
|
|
|
|
Authentication data in templates
|
|
================================
|
|
|
|
The currently logged-in user and his/her permissions are made available in the
|
|
:ref:`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.core.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
|
|
|
|
{% 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
|
|
|
|
{% 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
|
|
========
|
|
|
|
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
|
|
:ref:`template context <ref-templates-api>` as the template variable
|
|
``{{ messages }}``. Here's an example of template code that displays messages:
|
|
|
|
.. code-block:: html
|
|
|
|
{% if messages %}
|
|
<ul>
|
|
{% for message in messages %}
|
|
<li>{{ message }}</li>
|
|
{% endfor %}
|
|
</ul>
|
|
{% endif %}
|
|
|
|
Note that :class:`~django.template.context.RequestContext` calls
|
|
:meth:`~django.contrib.auth.models.User.get_and_delete_messages` behind the
|
|
scenes, so any messages will be deleted even if you don't display them.
|
|
|
|
Finally, note that this messages framework only works with users in the user
|
|
database. To send messages to anonymous users, use the
|
|
:ref:`session framework <topics-http-sessions>`.
|
|
|
|
.. _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 :ref:`authentication backend reference <ref-authentication-backends>`
|
|
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` 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
|