# Documentazione Django 6.0.7

# `django.contrib.auth`

This document provides API reference material for the components of Django’s authentication system. For more details on the usage of these components or how to customize authentication and authorization see the authentication topic guide.

## `User` model

class models.User

### Fields

class models.User

  `User` objects have the following fields:

  username

    Required. 150 characters or fewer. Usernames may contain alphanumeric, `_`, `@`, `+`, `.` and `-` characters.

    The `max_length` should be sufficient for many use cases. If you need a longer length, please use a custom user model.

  first_name

    Optional (`blank=True`). 150 characters or fewer.

  last_name

    Optional (`blank=True`). 150 characters or fewer.

  email

    Optional (`blank=True`). Email address.

  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. The metadata in this field may mark the password as unusable. See the password documentation.

  groups

    Many-to-many relationship to `Group`

  user_permissions

    Many-to-many relationship to `Permission`

  is_staff

    Boolean. Allows this user to access the admin site.

  is_active

    Boolean. Marks this user account as 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 but the default backend (`ModelBackend`) and the `RemoteUserBackend` do. You can use `AllowAllUsersModelBackend` or `AllowAllUsersRemoteUserBackend` if you want to allow inactive users to login. In this case, you’ll also want to customize the `AuthenticationForm` used by the `LoginView` as it rejects inactive users. Be aware that the permission-checking methods such as `has_perm()` and the authentication in the Django admin all return `False` for inactive users.

  is_superuser

    Boolean. Treats this user as having all permissions without assigning any permission to it in particular.

  last_login

    A datetime of the user’s last login.

  date_joined

    The date/time when the account was created.

### Attributes

class models.User
  is_authenticated

    Read-only attribute which is always `True` (as opposed to `AnonymousUser.is_authenticated` which is always `False`). 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 or has a valid session. Even though normally you will check this attribute on `request.user` to find out whether it has been populated by the `AuthenticationMiddleware` (representing the currently logged-in user), you should know this attribute is `True` for any `User` instance.

  is_anonymous

    Read-only attribute which is always `False`. This is a way of differentiating `User` and `AnonymousUser` objects. Generally, you should prefer using `is_authenticated` to this attribute.

### Methods

class models.User
  get_username()

    Returns the username for the user. Since the `User` model can be swapped out, you should use this method instead of referencing the username attribute directly.

  get_full_name()

    Returns the `first_name` plus the `last_name`, with a space in between.

  get_short_name()

    Returns the `first_name`.

  set_password(raw_password)

    Sets the user’s password to the given raw string, taking care of the password hashing. Doesn’t save the `User` object.

    When the `raw_password` is `None`, the password will be set to an unusable password, as if `set_unusable_password()` were used.

  check_password(raw_password)
  acheck_password(raw_password)

    Asynchronous version: `acheck_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.)

  set_unusable_password()

    Marks the user as having no password set by updating the metadata in the `password` field. This isn’t the same as having a blank string for a password. `check_password()` for this user will never return `True`. Doesn’t save the `User` object.

    You may need this if authentication for your application takes place against an existing external source such as an LDAP directory.

    Password reset restriction

    Users having an unusable password will not able to request a password reset email via `PasswordResetView`.

  has_usable_password()

    Returns `False` if `set_unusable_password()` has been called for this user.

  get_user_permissions(obj=None)
  aget_user_permissions(obj=None)

    Asynchronous version: `aget_user_permissions()`

    Returns a set of permission strings that the user has directly.

    If `obj` is passed in, only returns the user permissions for this specific object.

  get_group_permissions(obj=None)
  aget_group_permissions(obj=None)

    Asynchronous version: `aget_group_permissions()`

    Returns a set of permission strings that the user has, through their groups.

    If `obj` is passed in, only returns the group permissions for this specific object.

  get_all_permissions(obj=None)
  aget_all_permissions(obj=None)

    Asynchronous version: `aget_all_permissions()`

    Returns a set of permission strings that the user has, both through group and user permissions.

    If `obj` is passed in, only returns the permissions for this specific object.

  has_perm(perm, obj=None)
  ahas_perm(perm, obj=None)

    Asynchronous version: `ahas_perm()`

    Returns `True` if the user has the specified permission, where perm is in the format `"<app label>.<permission codename>"`. (see documentation on permissions). If the user is inactive, this method will always return `False`. For an active superuser, this method will always return `True`.

    If `obj` is passed in, this method won’t check for a permission for the model, but for this specific object.

  has_perms(perm_list, obj=None)
  ahas_perms(perm_list, obj=None)

    Asynchronous version: `ahas_perms()`

    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`. For an active superuser, this method will always return `True`.

    If `obj` is passed in, this method won’t check for permissions for the model, but for the specific object.

  has_module_perms(package_name)
  ahas_module_perms(package_name)

    Asynchronous version: `ahas_module_perms()`

    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`. For an active superuser, this method will always return `True`.

  email_user(subject, message, from_email=None, **kwargs)

    Sends an email to the user. If `from_email` is `None`, Django uses the `DEFAULT_FROM_EMAIL`. Any `**kwargs` are passed to the underlying `send_mail()` call.

### Manager methods

class models.UserManager

  The `User` model has a custom manager that has the following helper methods (in addition to the methods provided by `BaseUserManager`):

  create_user(username, email=None, password=None, **extra_fields)
  acreate_user(username, email=None, password=None, **extra_fields)

    Asynchronous version: `acreate_user()`

    Creates, saves and returns a `User`.

    The `username` and `password` are set as given. The domain portion of `email` is automatically converted to lowercase, and the returned `User` object will have `is_active` set to `True`.

    If no password is provided, `set_unusable_password()` will be called.

    If no email is provided, `email` will be set to an empty string.

    The `extra_fields` keyword arguments are passed through to the `User`’s `__init__` method to allow setting arbitrary fields on a custom user model.

    See Creating users for example usage.

  create_superuser(username, email=None, password=None, **extra_fields)
  acreate_superuser(username, email=None, password=None, **extra_fields)

    Asynchronous version: `acreate_superuser()`

    Same as `create_user()`, but sets `is_staff` and `is_superuser` to `True`.

  with_perm(perm, is_active=True, include_superusers=True, backend=None, obj=None)

    Returns users that have the given permission `perm` either in the `"<app label>.<permission codename>"` format or as a `Permission` instance. Returns an empty queryset if no users who have the `perm` found.

    If `is_active` is `True` (default), returns only active users, or if `False`, returns only inactive users. Use `None` to return all users irrespective of active state.

    If `include_superusers` is `True` (default), the result will include superusers.

    If `backend` is passed in and it’s defined in `AUTHENTICATION_BACKENDS`, then this method will use it. Otherwise, it will use the `backend` in `AUTHENTICATION_BACKENDS`, if there is only one, or raise an exception.

## `AnonymousUser` object

class models.AnonymousUser

  `django.contrib.auth.models.AnonymousUser` is a class that implements the `django.contrib.auth.models.User` interface, with these differences:

  - id is always `None`.

  - `username` is always the empty string.

  - `get_username()` always returns the empty string.

  - `is_anonymous` is `True` instead of `False`.

  - `is_authenticated` is `False` instead of `True`.

  - `is_staff` and `is_superuser` are always `False`.

  - `is_active` is always `False`.

  - `groups` and `user_permissions` are always empty.

  - `set_password()`, `check_password()`, `save()` and `delete()` raise `NotImplementedError`.

In practice, you probably won’t need to use `AnonymousUser` objects on your own, but they’re used by web requests, as explained in the next section.

## `Permission` model

class models.Permission

### Fields

`Permission` objects have the following fields:

class models.Permission
  name

    Required. 255 characters or fewer. Example: `'Can vote'`.

  content_type

    Required. A foreign key to the `ContentType` model.

  codename

    Required. 100 characters or fewer. Example: `'can_vote'`.

### Methods

`Permission` objects have the standard data-access methods like any other Django model.

class models.Permission
  user_perm_str
    New in Django 6.1.

    Returns the string representation for use in `has_perm`.

## `Group` model

class models.Group

### Fields

`Group` objects have the following fields:

class models.Group
  name

    Required. 150 characters or fewer. Any characters are permitted. Example: `'Awesome Users'`.

  permissions

    Many-to-many field to `Permission`:

        group.permissions.set([permission_list])
        group.permissions.add(permission, permission, ...)
        group.permissions.remove(permission, permission, ...)
        group.permissions.clear()

## Validators

class validators.ASCIIUsernameValidator

  A field validator allowing only ASCII letters and numbers, in addition to `@`, `.`, `+`, `-`, and `_`.

class validators.UnicodeUsernameValidator

  A field validator allowing Unicode characters, in addition to `@`, `.`, `+`, `-`, and `_`. The default validator for `User.username`.

## Login and logout signals

The auth framework uses the following signals that can be used for notification when a user logs in or out.

user_logged_in

  Sent when a user logs in successfully.

  Arguments sent with this signal:

  `sender`

    The class of the user that just logged in.

  `request`

    The current `HttpRequest` instance.

  `user`

    The user instance that just logged in.

user_logged_out

  Sent when the logout method is called.

  `sender`

    As above: the class of the user that just logged out or `None` if the user was not authenticated.

  `request`

    The current `HttpRequest` instance.

  `user`

    The user instance that just logged out or `None` if the user was not authenticated.

user_login_failed

  Sent when the user failed to login successfully

  `sender`

    The name of the module used for authentication.

  `credentials`

    A dictionary of keyword arguments containing the user credentials that were passed to `authenticate()` or your own custom authentication backend. Credentials matching a set of “sensitive” patterns (including password) will not be sent in the clear as part of the signal.

  `request`

    The `HttpRequest` object, if one was provided to `authenticate()`.

## Authentication backends

This section details the authentication backends that come with Django. For information on how to use them and how to write your own authentication backends, see the Other authentication sources section of the User authentication guide.

### Available authentication backends

The following backends are available in `django.contrib.auth.backends`:

class BaseBackend

  A base class that provides default implementations for all required methods. By default, it will reject any user and provide no permissions.

  get_user_permissions(user_obj, obj=None)
  aget_user_permissions(user_obj, obj=None)

    Asynchronous version: `aget_user_permissions()`

    Returns an empty set.

  get_group_permissions(user_obj, obj=None)
  aget_group_permissions(user_obj, obj=None)

    Asynchronous version: `aget_group_permissions()`

    Returns an empty set.

  get_all_permissions(user_obj, obj=None)
  aget_all_permissions(user_obj, obj=None)

    Asynchronous version: `aget_all_permissions()`

    Uses `get_user_permissions()` and `get_group_permissions()` to get the set of permission strings the `user_obj` has.

  has_perm(user_obj, perm, obj=None)
  ahas_perm(user_obj, perm, obj=None)

    Asynchronous version: `ahas_perm()`

    Uses `get_all_permissions()` to check if `user_obj` has the permission string `perm`.

class ModelBackend

  This is the default authentication backend used by Django. It authenticates using credentials consisting of a user identifier and password. For Django’s default user model, the user identifier is the username, for custom user models it is the field specified by USERNAME_FIELD (see Customizing Users and authentication).

  It also handles the default permissions model as defined for `User` and `PermissionsMixin`.

  `has_perm()`, `get_all_permissions()`, `get_user_permissions()`, and `get_group_permissions()` allow an object to be passed as a parameter for object-specific permissions, but this backend does not implement them other than returning an empty set of permissions if `obj is not None`.

  `with_perm()` also allows an object to be passed as a parameter, but unlike other methods it returns an empty queryset if `obj is not None`.

  authenticate(request, username=None, password=None, **kwargs)
  aauthenticate(request, username=None, password=None, **kwargs)

    Asynchronous version: `aauthenticate()`

    Tries to authenticate `username` with `password` by calling `User.check_password`. If no `username` is provided, it tries to fetch a username from `kwargs` using the key `CustomUser.USERNAME_FIELD`. Returns an authenticated user or `None`.

    `request` is an `HttpRequest` and may be `None` if it wasn’t provided to `authenticate()` (which passes it on to the backend).

  get_user_permissions(user_obj, obj=None)
  aget_user_permissions(user_obj, obj=None)

    Asynchronous version: `aget_user_permissions()`

    Returns the set of permission strings the `user_obj` has from their own user permissions. Returns an empty set if `is_anonymous` or `is_active` is `False`.

  get_group_permissions(user_obj, obj=None)
  aget_group_permissions(user_obj, obj=None)

    Asynchronous version: `aget_group_permissions()`

    Returns the set of permission strings the `user_obj` has from the permissions of the groups they belong. Returns an empty set if `is_anonymous` or `is_active` is `False`.

  get_all_permissions(user_obj, obj=None)
  aget_all_permissions(user_obj, obj=None)

    Asynchronous version: `aget_all_permissions()`

    Returns the set of permission strings the `user_obj` has, including both user permissions and group permissions. Returns an empty set if `is_anonymous` or `is_active` is `False`.

  has_perm(user_obj, perm, obj=None)
  ahas_perm(user_obj, perm, obj=None)

    Asynchronous version: `ahas_perm()`

    Uses `get_all_permissions()` to check if `user_obj` has the permission string `perm`. Returns `False` if the user is not `is_active`.

  has_module_perms(user_obj, app_label)
  ahas_module_perms(user_obj, app_label)

    Asynchronous version: `ahas_module_perms()`

    Returns whether the `user_obj` has any permissions on the app `app_label`.

  user_can_authenticate()

    Returns whether the user is allowed to authenticate. To match the behavior of `AuthenticationForm.confirm_login_allowed()`, this method returns `False` for users with `is_active=False`. Custom user models that don’t have an `is_active` field are allowed.

  with_perm(perm, is_active=True, include_superusers=True, obj=None)

    Returns all active users who have the permission `perm` either in the form of `"<app label>.<permission codename>"` or a `Permission` instance. Returns an empty queryset if no users who have the `perm` found.

    If `is_active` is `True` (default), returns only active users, or if `False`, returns only inactive users. Use `None` to return all users irrespective of active state.

    If `include_superusers` is `True` (default), the result will include superusers.

class AllowAllUsersModelBackend

  Same as `ModelBackend` except that it doesn’t reject inactive users because `user_can_authenticate()` always returns `True`.

  When using this backend, you’ll likely want to customize the `AuthenticationForm` used by the `LoginView` by overriding the `confirm_login_allowed()` method as it rejects inactive users.

class RemoteUserBackend

  Use this backend to take advantage of external-to-Django-handled authentication. It authenticates using usernames passed in `request.META['REMOTE_USER']`. See the Authenticating against REMOTE_USER documentation.

  If you need more control, you can create your own authentication backend that inherits from this class and override these attributes or methods:

  create_unknown_user

    `True` or `False`. Determines whether or not a user object is created if not already in the database Defaults to `True`.

  authenticate(request, remote_user)
  aauthenticate(request, remote_user)

    Asynchronous version: `aauthenticate()`

    The username passed as `remote_user` is considered trusted. This method returns the user object with the given username, creating a new user object if `create_unknown_user` is `True`.

    Returns `None` if `create_unknown_user` is `False` and a `User` object with the given username is not found in the database.

    `request` is an `HttpRequest` and may be `None` if it wasn’t provided to `authenticate()` (which passes it on to the backend).

  clean_username(username)

    Performs any cleaning on the `username` (e.g. stripping LDAP DN information) prior to using it to get or create a user object. Returns the cleaned username.

  configure_user(request, user, created=True)
  aconfigure_user(request, user, created=True)

    Asynchronous version: `aconfigure_user()`

    Configures the user on each authentication attempt. This method is called immediately after fetching or creating the user being authenticated, and can be used to perform custom setup actions, such as setting the user’s groups based on attributes in an LDAP directory. Returns the user object. When fetching or creating an user is called from a synchronous context, `configure_user` is called, `aconfigure_user` is called from async contexts.

    The setup can be performed either once when the user is created (`created` is `True`) or on existing users (`created` is `False`) as a way of synchronizing attributes between the remote and the local systems.

    `request` is an `HttpRequest` and may be `None` if it wasn’t provided to `authenticate()` (which passes it on to the backend).

  user_can_authenticate()

    Returns whether the user is allowed to authenticate. This method returns `False` for users with `is_active=False`. Custom user models that don’t have an `is_active` field are allowed.

class AllowAllUsersRemoteUserBackend

  Same as `RemoteUserBackend` except that it doesn’t reject inactive users because `user_can_authenticate` always returns `True`.

## Utility functions

get_user(request)

aget_user(request)

  Asynchronous version: `aget_user()`

  Returns the user model instance associated with the given `request`’s session.

  It checks if the authentication backend stored in the session is present in `AUTHENTICATION_BACKENDS`. If so, it uses the backend’s `get_user()` method to retrieve the user model instance and then verifies the session by calling the user model’s `get_session_auth_hash()` method. If the verification fails and `SECRET_KEY_FALLBACKS` are provided, it verifies the session against each fallback key using `get_session_auth_fallback_hash()`.

  Returns an instance of `AnonymousUser` if the authentication backend stored in the session is no longer in `AUTHENTICATION_BACKENDS`, if a user isn’t returned by the backend’s `get_user()` method, or if the session auth hash doesn’t validate.