Building a MWE with email login and custom signup form: why is a custom adapter required?

[PieterjanRobbe]

Hi all,

I'm considering implementing django-allauth on my website. Before doing so, I want to build a minimal working example (MWE) for my specific use case: users use email to login, and sign up using a custom form.

Adding a custom user model to support email login is pretty easy, according to the documentation:

ACCOUNT_USER_MODEL_USERNAME_FIELD = None
ACCOUNT_EMAIL_REQUIRED = True
ACCOUNT_USERNAME_REQUIRED = False
ACCOUNT_LOGIN_METHODS = {"email"}

ACCOUNT_EMAIL_VERIFICATION = "none"  # Turned off for now

Now let's say I have a custom app my_app with a custom user model

# my_project/my_app/models.py
from django.contrib.auth.models import AbstractUser
from django.db import models

class CustomUser(AbstractUser):
    is_awesome = models.BooleanField(default=False)

# my_project/settings.py
AUTH_USER_MODEL = "my_app.CustomUser"

I also have a custom signup form

# my_project/my_app/forms.py
from django import forms
from .models import CustomUser

class CustomUserCreationForm(forms.ModelForm):

    class Meta:
        model = CustomUser
        fields = ("is_awesome", )

    # Required by django-allauth
    def signup(self, request, user):
        pass

# my_project/settings.py
ACCOUNT_SIGNUP_FORM_CLASS = "my_app.forms.CustomUserCreationForm"

Now, let's say I want to add 2 users to my database:

from django.test import TestCase
from django.urls import reverse

class CustomUserCreationFormTest(TestCase):
    def test_users(self):

        form_data_1 = {
            "email": "[email protected]",
            "password1": "securepassword1",
            "password2": "securepassword1",
            "is_awesome": True,
        }
        form_data_2 = {
            "email": "[email protected]",
            "password1": "securepassword2",
            "password2": "securepassword2",
            "is_awesome": False,
        }

        # First signup attempt
        response = self.client.post(reverse("account_signup"), data=form_data_1, follow=True)
        self.assertEqual(response.status_code, 200)

        # Logout
        self.client.post(reverse("account_logout"), follow=True)

        # Second signup attempt
        response = self.client.post(reverse("account_signup"), data=form_data_2, follow=True)

However, this tests fails with (full stack trace below)

django.db.utils.IntegrityError: UNIQUE constraint failed: my_app_customuser.username

The issue seems to be that allauth is not able to generate a unique username for these two users.

I can fix the test by adding a custom adapter with a custom save method, or a custom populate_username method that uses the email us the username, like this:

# my_project/my_app/adapter.py
from allauth.account.adapter import DefaultAccountAdapter
from allauth.account.utils import user_email, user_field

class CustomAccountAdapter(DefaultAccountAdapter):
    
    # Use email as username
    def populate_username(self, request, user):
        email = user_email(user)
        user_field(user, "username", email)

# my_project/settings.py
ACCOUNT_ADAPTER = "my_app.adapter.CustomAccountAdapter"

Why is this adapter required? What am I missing?

Full stack trace

Found 1 test(s).
Creating test database for alias 'default'...
System check identified no issues (0 silenced).
E
======================================================================
ERROR: test_users (my_app.tests.CustomUserCreationFormTest.test_users)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
  File "django/db/backends/sqlite3/base.py", line 354, in execute
    return super().execute(query, params)
sqlite3.IntegrityError: UNIQUE constraint failed: my_app_customuser.username

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "my_app/tests.py", line 36, in test_users
    response = self.client.post(reverse("account_signup"), data=form_data_2, follow=True)
  File "django/test/client.py", line 1158, in post
    response = super().post(path, **extra)
  File "django/test/client.py", line 503, in post
    return self.generic("POST", path, **extra)
  File "django/test/client.py", line 676, in generic
    return self.request(**r)
  File "django/test/client.py", line 1092, in request
    self.check_exception(response)
  File "django/test/client.py", line 805, in check_exception
    raise exc_value
  File "django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "django/views/generic/base.py", line 104, in view
    return self.dispatch(request, *args, **kwargs)
  File "django/utils/decorators.py", line 48, in _wrapper
    return bound_method(*args, **kwargs)
  File "allauth/decorators.py", line 12, in wrap
    resp = function(request, *args, **kwargs)
  File "allauth/account/views.py", line 158, in dispatch
    return super().dispatch(request, *args, **kwargs)
  File "allauth/account/forms.py", line 443, in try_save
    return super().try_save(request)
  File "allauth/account/forms.py", line 377, in try_save
    user = self.save(request)
  File "allauth/account/forms.py", line 387, in save
    adapter.save_user(request, user, self)
  File "allauth/account/adapter.py", line 331, in save_user
    user.save()
  File "django/db/models/base.py", line 892, in save
    self.save_base(using=using, update_fields=update_fields)
  File "django/db/models/base.py", line 998, in save_base
    updated = self._save_table(raw, cls._base_manager, using, fields, returning_fields)
  File "django/db/models/base.py", line 1161, in _save_table
    results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw)
  File "django/db/models/base.py", line 1202, in _do_insert
    return manager._insert([self], **kwargs)
  File "django/db/models/manager.py", line 87, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "django/db/models/query.py", line 1847, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File "django/db/models/sql/compiler.py", line 1836, in execute_sql
    cursor.execute(sql, params)
  File "django/db/backends/utils.py", line 79, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "django/db/backends/utils.py", line 92, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "django/db/backends/utils.py", line 100, in _execute
    with self.db.wrap_database_errors:
  File "django/db/utils.py", line 91, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "django/db/backends/utils.py", line 105, in _execute
    return self.cursor.execute(sql, params)
  File "django/db/backends/sqlite3/base.py", line 354, in execute
    return super().execute(query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: my_app_customuser.username

----------------------------------------------------------------------
Ran 1 test in 0.384s

FAILED (errors=1)
Destroying test database for alias 'default'...

[pennersr]

Your user model does have a username field, yet, by configuring this you are informing allauth there is no such field:

ACCOUNT_USER_MODEL_USERNAME_FIELD = None

As a result, allauth won't make any attempt to populate it with a unique value.

[PieterjanRobbe]

Got it, thanks @pennersr! Seems like I misunderstood the documentation on custom user models.

So either I keep the custom user model as is, but carry around a username field in the data base and set

ACCOUNT_USER_MODEL_USERNAME_FIELD = "username"

or I update the user model so that it does not have a username field

from django.contrib.auth.models import AbstractBaseUser
from django.db import models

class CustomUser(AbstractBaseUser):
    email = models.EmailField(unique=True)
    is_awesome = models.BooleanField(default=False)

    USERNAME_FIELD = "email"

and keep

ACCOUNT_USER_MODEL_USERNAME_FIELD = None

Both of these work and do not require the custom adapter.