Django Allauth自定义注册表单问题：cpf_cnpj字段无法保存至用户模型的解决方法

Hey there! Let's break down why your cpf_cnpj field isn't saving, and how to fix it:

The Root Cause #

Your default Django User model doesn't include a cpf_cnpj field—this is why first_name and last_name work (they're built-in fields), but your custom field gets ignored. You have two solid options to resolve this:

Option 1: Extend the Django User Model (Recommended for New Projects) #

If you're early in your project, replacing the default User model with a custom one is the cleanest approach:

1. Create a Custom User Model in models.py:

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

class CustomUser(AbstractUser):
    # Add your custom field here
    cpf_cnpj = models.CharField(max_length=14)

2. Update Settings to use your new model in settings.py:

# Replace 'mysite' with your app name
AUTH_USER_MODEL = 'mysite.CustomUser'

3. Run Migrations to apply the changes to your database:

python manage.py makemigrations
python manage.py migrate

4. Fix Your Form's Save Method (note the typo correction!):

class MyCustomSignupForm(SignupForm):
    cpf_cnpj = forms.CharField(max_length=14)
    first_name = forms.CharField(max_length=30)
    last_name = forms.CharField(max_length=30)

    def save(self, request):
        user = super(MyCustomSignupForm, self).save(request)
        # Fixed the typo: cleanedD_data → cleaned_data
        user.first_name = self.cleaned_data['first_name']
        user.last_name = self.cleaned_data['last_name']
        user.cpf_cnpj = self.cleaned_data['cpf_cnpj']
        user.save()
        return user

Option 2: Use a Separate Profile Model (Good for Existing Projects) #

If you can't replace the default User model (e.g., your project is already in progress), create a one-to-one linked profile model:

1. Create a Profile Model in models.py:

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

class UserProfile(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    cpf_cnpj = models.CharField(max_length=14)

2. Update Your Form's Save Method to create/update the profile:

class MyCustomSignupForm(SignupForm):
    cpf_cnpj = forms.CharField(max_length=14)
    first_name = forms.CharField(max_length=30)
    last_name = forms.CharField(max_length=30)

    def save(self, request):
        user = super(MyCustomSignupForm, self).save(request)
        # Fix the typo here too!
        user.first_name = self.cleaned_data['first_name']
        user.last_name = self.cleaned_data['last_name']
        user.save()

        # Create or get the existing profile for the user
        profile, created = UserProfile.objects.get_or_create(user=user)
        profile.cpf_cnpj = self.cleaned_data['cpf_cnpj']
        profile.save()

        return user

3. Run Migrations to create the profile table:

python manage.py makemigrations
python manage.py migrate

Quick Note: Typo Fix! #

I noticed you had cleanedD_data (capital D) in your original code for last_name—that's a typo! Even if you said last_name was saving, fixing that will ensure it works reliably.

内容的提问来源于stack exchange，提问作者Jorge Marques