How to add max_length to allauth username

问题

I'm using Django allauth as my user account framework for my django site. The docs show there is an ACCOUNT_USERNAME_MIN_LENGTH however there is no ACCOUNT_USERNAME_MAX_LENGTH for some reason.

Is there any way to create a max length for username?

Here's my custom allauth signup form - maybe I can do something here?:

class AllauthSignupForm(forms.Form):

    captcha = ReCaptchaField(
        public_key=config("RECAPTCHA_PUBLIC_KEY"),
        private_key=config("RECAPTCHA_PRIVATE_KEY"),
    )

    class Meta:
        model = User

    def signup(self, request, user):
        """ Required, or else it throws deprecation warnings """
        pass

Edit: Trying to subclass SignupView

draft1/forms.py

class AllauthSignupForm(SignupForm):
    def __init__(self, *args, **kwargs):
        super(AllauthSignupForm, self).__init__(*args, **kwargs)
        self.fields['username']['validators'] += MaxLengthValidator(150,
                                                                    "Username should be less than 150 character long")

    captcha = ReCaptchaField(
        public_key=config("RECAPTCHA_PUBLIC_KEY"),
        private_key=config("RECAPTCHA_PRIVATE_KEY"),
    )

    class Meta:
        model = User

    def signup(self, request, user):
        """ Required, or else it throws deprecation warnings """
        pass

draft1/views.py

from allauth.account.views import SignupView

class MySignupView(SignupView):
    form_class = AllauthSignupForm

allauth/account/urls.py

url(r"^signup/$", MySignupView.as_view(), name="account_signup"),

draft1/settings.py

ACCOUNT_SIGNUP_FORM_CLASS = 'draft1.forms.AllauthSignupForm'

The above code returns this error:

Traceback (most recent call last):
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/utils/autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/commands/runserver.py", line 125, in inner_run
    self.check(display_num_errors=True)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/base.py", line 359, in check
    include_deployment_checks=include_deployment_checks,
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/management/base.py", line 346, in _run_checks
    return checks.run_checks(**kwargs)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/checks/registry.py", line 81, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/checks/urls.py", line 16, in check_url_config
    return check_resolver(resolver)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/core/checks/urls.py", line 26, in check_resolver
    return check_method()
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/urls/resolvers.py", line 254, in check
    for pattern in self.url_patterns:
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/urls/resolvers.py", line 405, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/django/urls/resolvers.py", line 398, in urlconf_module
    return import_module(self.urlconf_name)
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 665, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/Users/zorgan/Desktop/vorsso/venvor/draft1/urls.py", line 6, in <module>
    from . import views
  File "/Users/zorgan/Desktop/vorsso/venvor/draft1/views.py", line 11, in <module>
    from .forms import UserSettingsForm
  File "/Users/zorgan/Desktop/vorsso/venvor/draft1/forms.py", line 8, in <module>
    from allauth.account.forms import SignupForm
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/allauth/account/forms.py", line 228, in <module>
    class BaseSignupForm(_base_signup_form_class()):
  File "/Users/zorgan/Desktop/postr1/lib/python3.5/site-packages/allauth/account/forms.py", line 216, in _base_signup_form_class
    fc_classname))
django.core.exceptions.ImproperlyConfigured: Module "draft1.forms" does not define a "AllauthSignupForm" class

回答1:

This can be quickly done by extending DefaultAccountAdapter class and overriding the clean_username method. You need to also reference the clean_username once again after our custom validation to complete other inbuilt validations.

It can be done as follows.

from allauth.account.adapter import DefaultAccountAdapter
from django.forms import ValidationError

class UsernameMaxAdapter(DefaultAccountAdapter):

    def clean_username(self, username):
        if len(username) > 'Your Max Size':
            raise ValidationError('Please enter a username value less than the current one')
        return DefaultAccountAdapter.clean_username(self,username) # For other default validations.

Finally, point to the subclass in your settings.py

ACCOUNT_ADAPTER = 'YourProject.adapter.UsernameMaxAdapter'

Reference: https://github.com/pennersr/django-allauth/blob/8fbbf8c1d32832d72de5ed1c7fd77600af57ea6f/allauth/account/adapter.py#L244

回答2:

You should use a max length validator like below. More documentation about validators here.

from django.core.validators import MaxLengthValidator
from allauth.account.forms import SignupForm
class AllauthSignupForm(SignupForm):
    def __init__(self, *args, **kwargs):
        self.fields['username']['validators'] += MaxLengthValidator(150, "Username should be less than 150 character long")

回答3:

Not sure if this is the best way but it works.

After extending the SignupForm, Completely changed the username field with a new one that has the max_length parameter.

from django import forms
from django.utils.translation import ugettext_lazy as _
from allauth.account.forms import SignupForm

class AllauthSignupForm(SignupForm):
    username = forms.CharField(label=_("Username"),
                               min_length=5,
                               max_length=20, # Change this 
                               widget=forms.TextInput(
                                   attrs={'placeholder':
                                              _('Username'),
                                          'autofocus': 'autofocus'}))

回答4:

I would like to explain why there is no ACCOUNT_USERNAME_MAX_LENGTH. If you open source code you will see that max_length validator comes from username model field https://github.com/pennersr/django-allauth/blob/330bf899dd77046fd0510221f3c12e69eb2bc64d/allauth/account/forms.py#L277

username_field.max_length = get_username_max_length()

Where get_username_max_length is function that actually pulls max_length value from User model https://github.com/pennersr/django-allauth/blob/8fbbf8c1d32832d72de5ed1c7fd77600af57ea6f/allauth/utils.py#L64

def get_username_max_length():
    from .account.app_settings import USER_MODEL_USERNAME_FIELD
    if USER_MODEL_USERNAME_FIELD is not None:
        User = get_user_model()
        max_length = User._meta.get_field(USER_MODEL_USERNAME_FIELD).max_length
    else:
        max_length = 0
    return max_length

First approach: So you could change max_length value directly on your User's model username field if you have it swapped.

I don't think overriding form fields or __init__ method will actually work the it suggested by other answers, because assign of max_length happens in subclass of ACCOUNT_SIGNUP_FORM_CLASS https://github.com/pennersr/django-allauth/blob/330bf899dd77046fd0510221f3c12e69eb2bc64d/allauth/account/forms.py#L259

class BaseSignupForm(_base_signup_form_class()):

where _base_signup_form_class is function that gets your ACCOUNT_SIGNUP_FORM_CLASS

Second approach: is to subclass SignupView and override it's SignupForm read Override signup view django-allauth and How to customize user profile when using django-allauth

In that SignupForm you could actually do what @MehdiB or @PeterSobhi suggested.

ImproperlyConfigured issue occurs because of https://github.com/pennersr/django-allauth/issues/1792

So you be sure that these forms are defined in different python modules as per https://github.com/pennersr/django-allauth/issues/1749#issuecomment-304628013

# base/forms.py 
# this is form that your ACCOUNT_SIGNUP_FORM_CLASS is points to
class BaseSignupForm(forms.Form):

    captcha = ReCaptchaField(
        public_key=config("RECAPTCHA_PUBLIC_KEY"),
        private_key=config("RECAPTCHA_PRIVATE_KEY"),
    )

    class Meta:
        model = User

    def signup(self, request, user):
        """ Required, or else it throws deprecation warnings """
        pass

# data1/forms.py
# this is your signup form
from django.core.validators import MaxLengthValidator
from allauth.account.forms import SignupForm

class MySignupForm(SignupForm):
    def __init__(self, *args, **kwargs):
        super(MySignupForm, self).__init__(*args, **kwargs)
        self.fields['username']['validators'] += MaxLengthValidator(150, "Username should be less than 150 character long")

# views.py

from allauth.account.views import SignupView
class MySignupView(SignupView):
    form_class = MySignupForm

# urls.py

url(r"^signup/$", MySignupView.as_view(), name="account_signup"),

回答5:

Try importing with the full name like in your forms : from allauth.accouts import forms as AllauthForms class AllauthSignupForm(AllauthForms.SignupForm): ....

i didn't test this and sorry i posted this with my phone i will reformat the answer soon

来源：https://stackoverflow.com/questions/50548685/how-to-add-max-length-to-allauth-username