The authentication that comes with Django is good enough for most common cases,\nbut you may have needs not met by the out-of-the-box defaults. To customize\nauthentication to your projects needs involves understanding what points of the\nprovided system are extensible or replaceable. This document provides details\nabout how the auth system can be customized.
\nAuthentication backends provide an extensible\nsystem for when a username and password stored with the User model need\nto be authenticated against a different service than Django's default.
\nYou can give your models custom permissions that can be\nchecked through Django's authorization system.
\nYou can extend the default User model, or substitute a completely customized model.
\nThere may be times you have the need to hook into another authentication source\n-- that is, another source of usernames and passwords or authentication\nmethods.
\nFor example, your company may already have an LDAP setup that stores a username\nand password for every employee. It'd be a hassle for both the network\nadministrator and the users themselves if users had separate accounts in LDAP\nand the Django-based applications.
\nSo, to handle situations like this, the Django authentication system lets you\nplug in other authentication sources. You can override Django's default\ndatabase-based scheme, or you can use the default system in tandem with other\nsystems.
\nSee the authentication backend reference for information on the authentication\nbackends included with Django.
\nBehind the scenes, Django maintains a list of "authentication backends" that it\nchecks for authentication. When somebody calls\ndjango.contrib.auth.authenticate() -- as described in How to log\na user in -- Django tries authenticating across\nall of its authentication backends. If the first authentication method fails,\nDjango tries the second one, and so on, until all backends have been attempted.
The list of authentication backends to use is specified in the\nAUTHENTICATION_BACKENDS setting. This should be a list of Python\npath names that point to Python classes that know how to authenticate. These\nclasses can be anywhere on your Python path.
By default, AUTHENTICATION_BACKENDS is set to:
['django.contrib.auth.backends.ModelBackend']\nThat's the basic authentication backend that checks the Django users database\nand queries the built-in permissions. It does not provide protection against\nbrute force attacks via any rate limiting mechanism. You may either implement\nyour own rate limiting mechanism in a custom auth backend, or use the\nmechanisms provided by most Web servers.
\nThe order of AUTHENTICATION_BACKENDS matters, so if the same\nusername and password is valid in multiple backends, Django will stop\nprocessing at the first positive match.
If a backend raises a PermissionDenied\nexception, authentication will immediately fail. Django won't check the\nbackends that follow.
An authentication backend is a class that implements two required methods:\nget_user(user_id) and authenticate(**credentials), as well as a set of\noptional permission related authorization methods.
The get_user method takes a user_id -- which could be a username,\ndatabase ID or whatever, but has to be the primary key of your User object\n-- and returns a User object.
The authenticate method takes credentials as keyword arguments. Most of\nthe time, it'll just look like this:
class MyBackend(object):\n def authenticate(self, username=None, password=None):\n # Check the username/password and return a User.\n ...\nBut it could also authenticate a token, like so:
\nclass MyBackend(object):\n def authenticate(self, token=None):\n # Check the token and return a User.\n ...\nEither way, authenticate should check the credentials it gets, and it\nshould return a User object that matches those credentials, if the\ncredentials are valid. If they're not valid, it should return None.
The Django admin is tightly coupled to the Django User object. The best way to deal with this is to create a Django User\nobject for each user that exists for your backend (e.g., in your LDAP\ndirectory, your external SQL database, etc.) You can either write a script to\ndo this in advance, or your authenticate method can do it the first time a\nuser logs in.
Here's an example backend that authenticates against a username and password\nvariable defined in your settings.py file and creates a Django User\nobject the first time a user authenticates:
from django.conf import settings\nfrom django.contrib.auth.hashers import check_password\nfrom django.contrib.auth.models import User\n\nclass SettingsBackend(object):\n """\n Authenticate against the settings ADMIN_LOGIN and ADMIN_PASSWORD.\n\n Use the login name, and a hash of the password. For example:\n\n ADMIN_LOGIN = 'admin'\n ADMIN_PASSWORD = 'pbkdf2_sha256$30000$Vo0VlMnkR4Bk$qEvtdyZRWTcOsCnI/oQ7fVOu1XAURIZYoOZ3iq8Dr4M='\n """\n\n def authenticate(self, username=None, password=None):\n login_valid = (settings.ADMIN_LOGIN == username)\n pwd_valid = check_password(password, settings.ADMIN_PASSWORD)\n if login_valid and pwd_valid:\n try:\n user = User.objects.get(username=username)\n except User.DoesNotExist:\n # Create a new user. Note that we can set password\n # to anything, because it won't be checked; the password\n # from settings.py will.\n user = User(username=username, password='get from settings.py')\n user.is_staff = True\n user.is_superuser = True\n user.save()\n return user\n return None\n\n def get_user(self, user_id):\n try:\n return User.objects.get(pk=user_id)\n except User.DoesNotExist:\n return None\nTo create custom permissions for a given model object, use the permissions\nmodel Meta attribute.
This example Task model creates three custom permissions, i.e., actions users\ncan or cannot do with Task instances, specific to your application:
\nclass Task(models.Model):\n ...\n class Meta:\n permissions = (\n ("view_task", "Can see available tasks"),\n ("change_task_status", "Can change the status of tasks"),\n ("close_task", "Can remove a task by setting its status as closed"),\n )\nThe only thing this does is create those extra permissions when you run\nmanage.py migrate (the function that creates permissions\nis connected to the post_migrate signal).\nYour code is in charge of checking the value of these permissions when a user\nis trying to access the functionality provided by the application (viewing\ntasks, changing the status of tasks, closing tasks.) Continuing the above\nexample, the following checks if a user may view tasks:
user.has_perm('app.view_task')\nUser modelLink to this heading#There are two ways to extend the default\nUser model without substituting your own\nmodel. If the changes you need are purely behavioral, and don't require any\nchange to what is stored in the database, you can create a proxy model based on User. This\nallows for any of the features offered by proxy models including default\nordering, custom managers, or custom model methods.
If you wish to store information related to User, you can use a\nOneToOneField to a model containing the fields for\nadditional information. This one-to-one model is often called a profile model,\nas it might store non-auth related information about a site user. For example\nyou might create an Employee model:
from django.contrib.auth.models import User\n\nclass Employee(models.Model):\n user = models.OneToOneField(User, on_delete=models.CASCADE)\n department = models.CharField(max_length=100)\nAssuming an existing Employee Fred Smith who has both a User and Employee\nmodel, you can access the related information using Django's standard related\nmodel conventions:
\n>>> u = User.objects.get(username='fsmith')\n>>> freds_department = u.employee.department\nTo add a profile model's fields to the user page in the admin, define an\nInlineModelAdmin (for this example, we'll use a\nStackedInline) in your app's admin.py and\nadd it to a UserAdmin class which is registered with the\nUser class:
from django.contrib import admin\nfrom django.contrib.auth.admin import UserAdmin as BaseUserAdmin\nfrom django.contrib.auth.models import User\n\nfrom my_user_profile_app.models import Employee\n\n# Define an inline admin descriptor for Employee model\n# which acts a bit like a singleton\nclass EmployeeInline(admin.StackedInline):\n model = Employee\n can_delete = False\n verbose_name_plural = 'employee'\n\n# Define a new User admin\nclass UserAdmin(BaseUserAdmin):\n inlines = (EmployeeInline, )\n\n# Re-register UserAdmin\nadmin.site.unregister(User)\nadmin.site.register(User, UserAdmin)\nThese profile models are not special in any way - they are just Django models that\nhappen to have a one-to-one link with a User model. As such, they do not get\nauto created when a user is created, but\na django.db.models.signals.post_save could be used to create or update\nrelated models as appropriate.
Note that using related models results in additional queries or joins to\nretrieve the related data, and depending on your needs substituting the User\nmodel and adding the related fields may be your better option. However\nexisting links to the default User model within your project's apps may justify\nthe extra database load.
\nUser modelLink to this heading#Some kinds of projects may have authentication requirements for which Django's\nbuilt-in User model is not always\nappropriate. For instance, on some sites it makes more sense to use an email\naddress as your identification token instead of a username.
Django allows you to override the default User model by providing a value for\nthe AUTH_USER_MODEL setting that references a custom model:
AUTH_USER_MODEL = 'myapp.MyUser'\nThis dotted pair describes the name of the Django app (which must be in your\nINSTALLED_APPS), and the name of the Django model that you wish to\nuse as your User model.
User modelLink to this heading#If you reference User directly (for\nexample, by referring to it in a foreign key), your code will not work in\nprojects where the AUTH_USER_MODEL setting has been changed to a\ndifferent User model.
Instead of referring to User directly,\nyou should reference the user model using\ndjango.contrib.auth.get_user_model(). This method will return the\ncurrently active User model -- the custom User model if one is specified, or\nUser otherwise.
When you define a foreign key or many-to-many relations to the User model,\nyou should specify the custom model using the AUTH_USER_MODEL\nsetting. For example:
from django.conf import settings\nfrom django.db import models\n\nclass Article(models.Model):\n author = models.ForeignKey(\n settings.AUTH_USER_MODEL,\n on_delete=models.CASCADE,\n )\nWhen connecting to signals sent by the User model, you should specify\nthe custom model using the AUTH_USER_MODEL setting. For example:
from django.conf import settings\nfrom django.db.models.signals import post_save\n\ndef post_save_receiver(sender, instance, created, **kwargs):\n pass\n\npost_save.connect(post_save_receiver, sender=settings.AUTH_USER_MODEL)\nGenerally speaking, you should reference the User model with the\nAUTH_USER_MODEL setting in code that is executed at import\ntime. get_user_model() only works once Django has imported all models.
User modelLink to this heading#Django expects your custom User model to meet some minimum requirements.
\nIf you use the default authentication backend, then your model must have a\nsingle unique field that can be used for identification purposes. This can\nbe a username, an email address, or any other unique attribute. A non-unique\nusername field is allowed if you use a custom authentication backend that\ncan support it.
Your model must provide a way to address the user in a "short" and\n"long" form. The most common interpretation of this would be to use\nthe user's given name as the "short" identifier, and the user's full\nname as the "long" identifier. However, there are no constraints on\nwhat these two methods return - if you want, they can return exactly\nthe same value.
The easiest way to construct a compliant custom User model is to inherit from\nAbstractBaseUser.\nAbstractBaseUser provides the core\nimplementation of a User model, including hashed passwords and tokenized\npassword resets. You must then provide some key implementation details:
A string describing the name of the field on the User model that is\nused as the unique identifier. This will usually be a username of some\nkind, but it can also be an email address, or any other unique\nidentifier. The field must be unique (i.e., have unique=True set\nin its definition), unless you use a custom authentication backend that\ncan support non-unique usernames.
In the following example, the field identifier is used\nas the identifying field:
class MyUser(AbstractBaseUser):\n identifier = models.CharField(max_length=40, unique=True)\n ...\n USERNAME_FIELD = 'identifier'\nUSERNAME_FIELD now supports\nForeignKeys. Since there is no way to pass\nmodel instances during the createsuperuser prompt, expect the\nuser to enter the value of to_field\nvalue (the primary_key by default) of an\nexisting instance.
A list of the field names that will be prompted for when creating a\nuser via the createsuperuser management command. The user\nwill be prompted to supply a value for each of these fields. It must\ninclude any field for which blank is\nFalse or undefined and may include additional fields you want\nprompted for when a user is created interactively.\nREQUIRED_FIELDS has no effect in other parts of Django, like\ncreating a user in the admin.
For example, here is the partial definition for a User model that\ndefines two required fields - a date of birth and height:
class MyUser(AbstractBaseUser):\n ...\n date_of_birth = models.DateField()\n height = models.FloatField()\n ...\n REQUIRED_FIELDS = ['date_of_birth', 'height']\nREQUIRED_FIELDS now supports\nForeignKeys. Since there is no way to pass\nmodel instances during the createsuperuser prompt, expect the\nuser to enter the value of to_field\nvalue (the primary_key by default) of an\nexisting instance.
A boolean attribute that indicates whether the user is considered\n"active". This attribute is provided as an attribute on\nAbstractBaseUser defaulting to True. How you choose to\nimplement it will depend on the details of your chosen auth backends.\nSee the documentation of the is_active attribute on the built-in\nuser model for details.
A longer formal identifier for the user. A common interpretation\nwould be the full name of the user, but it can be any string that\nidentifies the user.
\nA short, informal identifier for the user. A common interpretation\nwould be the first name of the user, but it can be any string that\nidentifies the user in an informal way. It may also return the same\nvalue as django.contrib.auth.models.User.get_full_name().
The following methods are available on any subclass of\nAbstractBaseUser:
Returns the value of the field nominated by USERNAME_FIELD.
Always returns False. This is a way of differentiating\nfrom AnonymousUser objects.\nGenerally, you should prefer using\nis_authenticated() to this\nmethod.
Always returns True. This is a way to tell if the user has been\nauthenticated. This does not imply any permissions, and doesn't check\nif the user is active - it only indicates that the user has provided a\nvalid username and password.
Sets the user's password to the given raw string, taking care of the\npassword hashing. Doesn't save the\nAbstractBaseUser object.
When the raw_password is None, the password will be set to an\nunusable password, as if\nset_unusable_password()\nwere used.
Returns True if the given raw string is the correct password for\nthe user. (This takes care of the password hashing in making the\ncomparison.)
Marks the user as having no password set. This isn't the same as\nhaving a blank string for a password.\ncheck_password() for this user\nwill never return True. Doesn't save the\nAbstractBaseUser object.
You may need this if authentication for your application takes place\nagainst an existing external source such as an LDAP directory.
\nReturns False if\nset_unusable_password() has\nbeen called for this user.
Returns an HMAC of the password field. Used for\nSession invalidation on password change.
\nYou should also define a custom manager for your User model. If your\nUser model defines username, email, is_staff, is_active,\nis_superuser, last_login, and date_joined fields the same as\nDjango's default User, you can just install Django's\nUserManager; however, if your User\nmodel defines different fields, you will need to define a custom manager that\nextends BaseUserManager providing two\nadditional methods:
The prototype of create_user() should accept the username field,\nplus all required fields as arguments. For example, if your user model\nuses email as the username field, and has date_of_birth as a\nrequired field, then create_user should be defined as:
def create_user(self, email, date_of_birth, password=None):\n # create user here\n ...\nThe prototype of create_superuser() should accept the username\nfield, plus all required fields as arguments. For example, if your user\nmodel uses email as the username field, and has date_of_birth\nas a required field, then create_superuser should be defined as:
def create_superuser(self, email, date_of_birth, password):\n # create superuser here\n ...\nUnlike create_user(), create_superuser() must require the\ncaller to provide a password.
BaseUserManager provides the following\nutility methods:
Normalizes email addresses by lowercasing the domain portion of the\nemail address.
\nRetrieves a user instance using the contents of the field\nnominated by USERNAME_FIELD.
Returns a random password with the given length and given string of\nallowed characters. Note that the default value of allowed_chars\ndoesn't contain letters that can cause user confusion, including:
i, l, I, and 1 (lowercase letter i, lowercase\nletter L, uppercase letter i, and the number one)
o, O, and 0 (lowercase letter o, uppercase letter o,\nand zero)
UserLink to this heading#If you're entirely happy with Django's User\nmodel and you just want to add some additional profile information, you could\nsimply subclass django.contrib.auth.models.AbstractUser and add your\ncustom profile fields, although we'd recommend a separate model as described in\nthe "Model design considerations" note of Specifying a custom User model.\nAbstractUser provides the full implementation of the default\nUser as an abstract model.
Django's built-in forms and views make certain assumptions about the user model that they\nare working with.
\nThe following forms are compatible with any subclass of\nAbstractBaseUser:
AuthenticationForm: Uses the username\nfield specified by USERNAME_FIELD.
The following forms make assumptions about the user model and can be used as-is\nif those assumptions are met:
\nPasswordResetForm: Assumes that the user\nmodel has a field named email that can be used to identify the user and a\nboolean field named is_active to prevent password resets for inactive\nusers.
Finally, the following forms are tied to\nUser and need to be rewritten or extended\nto work with a custom user model:
If your custom user model is a simple subclass of AbstractUser, then you\ncan extend these forms in this manner:
from django.contrib.auth.forms import UserCreationForm\nfrom myapp.models import CustomUser\n\nclass CustomUserCreationForm(UserCreationForm):\n\n class Meta(UserCreationForm.Meta):\n model = CustomUser\n fields = UserCreationForm.Meta.fields + ('custom_field',)\ndjango.contrib.adminLink to this heading#If you want your custom User model to also work with Admin, your User model must\ndefine some additional attributes and methods. These methods allow the admin to\ncontrol access of the User to admin content:
\nReturns True if the user is allowed to have access to the admin site.
Returns True if the user account is currently active.
Returns True if the user has the named permission. If obj is\nprovided, the permission needs to be checked against a specific object\ninstance.
Returns True if the user has permission to access models in\nthe given app.
You will also need to register your custom User model with the admin. If\nyour custom User model extends django.contrib.auth.models.AbstractUser,\nyou can use Django's existing django.contrib.auth.admin.UserAdmin\nclass. However, if your User model extends\nAbstractBaseUser, you'll need to define\na custom ModelAdmin class. It may be possible to subclass the default\ndjango.contrib.auth.admin.UserAdmin; however, you'll need to\noverride any of the definitions that refer to fields on\ndjango.contrib.auth.models.AbstractUser that aren't on your\ncustom User class.
To make it easy to include Django's permission framework into your own User\nclass, Django provides PermissionsMixin.\nThis is an abstract model you can include in the class hierarchy for your User\nmodel, giving you all the methods and database fields necessary to support\nDjango's permission model.
PermissionsMixin provides the following\nmethods and attributes:
Boolean. Designates that this user has all permissions without\nexplicitly assigning them.
\nReturns a set of permission strings that the user has, through their\ngroups.
\nIf obj is passed in, only returns the group permissions for\nthis specific object.
Returns a set of permission strings that the user has, both through\ngroup and user permissions.
\nIf obj is passed in, only returns the permissions for this\nspecific object.
Returns True if the user has the specified permission, where\nperm is in the format "<app label>.<permission codename>" (see\npermissions). If the user is inactive, this method will\nalways return False.
If obj is passed in, this method won't check for a permission for\nthe model, but for this specific object.
Returns True if the user has each of the specified permissions,\nwhere each perm is in the format\n"<app label>.<permission codename>". If the user is inactive,\nthis method will always return False.
If obj is passed in, this method won't check for permissions for\nthe model, but for the specific object.
Returns True if the user has any permissions in the given package\n(the Django app label). If the user is inactive, this method will\nalways return False.
One limitation of custom User models is that installing a custom User model\nwill break any proxy model extending User.\nProxy models must be based on a concrete base class; by defining a custom User\nmodel, you remove the ability of Django to reliably identify the base class.
If your project uses proxy models, you must either modify the proxy to extend\nthe User model that is currently in use in your project, or merge your proxy's\nbehavior into your User subclass.
\nHere is an example of an admin-compliant custom user app. This user model uses\nan email address as the username, and has a required date of birth; it\nprovides no permission checking, beyond a simple admin flag on the user\naccount. This model would be compatible with all the built-in auth forms and\nviews, except for the User creation forms. This example illustrates how most of\nthe components work together, but is not intended to be copied directly into\nprojects for production use.
This code would all live in a models.py file for a custom\nauthentication app:
from django.db import models\nfrom django.contrib.auth.models import (\n BaseUserManager, AbstractBaseUser\n)\n\n\nclass MyUserManager(BaseUserManager):\n def create_user(self, email, date_of_birth, password=None):\n """\n Creates and saves a User with the given email, date of\n birth and password.\n """\n if not email:\n raise ValueError('Users must have an email address')\n\n user = self.model(\n email=self.normalize_email(email),\n date_of_birth=date_of_birth,\n )\n\n user.set_password(password)\n user.save(using=self._db)\n return user\n\n def create_superuser(self, email, date_of_birth, password):\n """\n Creates and saves a superuser with the given email, date of\n birth and password.\n """\n user = self.create_user(\n email,\n password=password,\n date_of_birth=date_of_birth,\n )\n user.is_admin = True\n user.save(using=self._db)\n return user\n\n\nclass MyUser(AbstractBaseUser):\n email = models.EmailField(\n verbose_name='email address',\n max_length=255,\n unique=True,\n )\n date_of_birth = models.DateField()\n is_active = models.BooleanField(default=True)\n is_admin = models.BooleanField(default=False)\n\n objects = MyUserManager()\n\n USERNAME_FIELD = 'email'\n REQUIRED_FIELDS = ['date_of_birth']\n\n def get_full_name(self):\n # The user is identified by their email address\n return self.email\n\n def get_short_name(self):\n # The user is identified by their email address\n return self.email\n\n def __str__(self): # __unicode__ on Python 2\n return self.email\n\n def has_perm(self, perm, obj=None):\n "Does the user have a specific permission?"\n # Simplest possible answer: Yes, always\n return True\n\n def has_module_perms(self, app_label):\n "Does the user have permissions to view the app `app_label`?"\n # Simplest possible answer: Yes, always\n return True\n\n @property\n def is_staff(self):\n "Is the user a member of staff?"\n # Simplest possible answer: All admins are staff\n return self.is_admin\nThen, to register this custom User model with Django's admin, the following\ncode would be required in the app's admin.py file:
from django import forms\nfrom django.contrib import admin\nfrom django.contrib.auth.models import Group\nfrom django.contrib.auth.admin import UserAdmin as BaseUserAdmin\nfrom django.contrib.auth.forms import ReadOnlyPasswordHashField\n\nfrom customauth.models import MyUser\n\n\nclass UserCreationForm(forms.ModelForm):\n """A form for creating new users. Includes all the required\n fields, plus a repeated password."""\n password1 = forms.CharField(label='Password', widget=forms.PasswordInput)\n password2 = forms.CharField(label='Password confirmation', widget=forms.PasswordInput)\n\n class Meta:\n model = MyUser\n fields = ('email', 'date_of_birth')\n\n def clean_password2(self):\n # Check that the two password entries match\n password1 = self.cleaned_data.get("password1")\n password2 = self.cleaned_data.get("password2")\n if password1 and password2 and password1 != password2:\n raise forms.ValidationError("Passwords don't match")\n return password2\n\n def save(self, commit=True):\n # Save the provided password in hashed format\n user = super(UserCreationForm, self).save(commit=False)\n user.set_password(self.cleaned_data["password1"])\n if commit:\n user.save()\n return user\n\n\nclass UserChangeForm(forms.ModelForm):\n """A form for updating users. Includes all the fields on\n the user, but replaces the password field with admin's\n password hash display field.\n """\n password = ReadOnlyPasswordHashField()\n\n class Meta:\n model = MyUser\n fields = ('email', 'password', 'date_of_birth', 'is_active', 'is_admin')\n\n def clean_password(self):\n # Regardless of what the user provides, return the initial value.\n # This is done here, rather than on the field, because the\n # field does not have access to the initial value\n return self.initial["password"]\n\n\nclass UserAdmin(BaseUserAdmin):\n # The forms to add and change user instances\n form = UserChangeForm\n add_form = UserCreationForm\n\n # The fields to be used in displaying the User model.\n # These override the definitions on the base UserAdmin\n # that reference specific fields on auth.User.\n list_display = ('email', 'date_of_birth', 'is_admin')\n list_filter = ('is_admin',)\n fieldsets = (\n (None, {'fields': ('email', 'password')}),\n ('Personal info', {'fields': ('date_of_birth',)}),\n ('Permissions', {'fields': ('is_admin',)}),\n )\n # add_fieldsets is not a standard ModelAdmin attribute. UserAdmin\n # overrides get_fieldsets to use this attribute when creating a user.\n add_fieldsets = (\n (None, {\n 'classes': ('wide',),\n 'fields': ('email', 'date_of_birth', 'password1', 'password2')}\n ),\n )\n search_fields = ('email',)\n ordering = ('email',)\n filter_horizontal = ()\n\n# Now register the new UserAdmin...\nadmin.site.register(MyUser, UserAdmin)\n# ... and, since we're not using Django's built-in permissions,\n# unregister the Group model from admin.\nadmin.site.unregister(Group)\nFinally, specify the custom model as the default user model for your project\nusing the AUTH_USER_MODEL setting in your settings.py:
AUTH_USER_MODEL = 'customauth.MyUser'\n