如何在 Django 中向用户 model 添加具有默认值的字段

Question

I need to add fields to the User model with default values that will not be displayed in the registration form but I am new to Django. How can I implement it and what am I doing wrong? models.py:

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


class CustomUser(AbstractUser):
    level = models.IntegerField(default=0)

forms.py:

from django import forms
from django.contrib.auth.forms import UserCreationForm, AuthenticationForm
from .models import CustomUser


class RegisterUserForm(UserCreationForm):
    username = forms.CharField(label="Имя", widget=forms.TextInput(attrs={'class': 'register__form-title form-control form-input',
                                                                          'placeholder': 'введите ваше имя'}))
    email = forms.CharField(label="Почта", widget=forms.TextInput(attrs={'class': 'register__form-title form-control form-control',
                                                                          'placeholder': 'введите вашу почту'}))
    password1 = forms.CharField(label="Пароль", widget=forms.TextInput(attrs={'class': 'register__form-title form-control form-input',
                                                                          'placeholder': 'введите пароль'}))
    password2 = forms.CharField(label="Подтверждение пароля", widget=forms.TextInput(attrs={'class': 'register__form-title form-control form-input',
                                                                          'placeholder': 'подтвердите ваш пароль'}))

    def __init__(self, *args, **kwargs):
        super(UserCreationForm, self).__init__(*args, **kwargs)
        for field_name in ['username', 'email', 'password1', 'password2']:
            self.fields[field_name].help_text = None

    class Meta:
        model = CustomUser
        fields = ('username', 'email', 'password1', 'password2')

views.py:

from django.contrib.auth import logout
from django.contrib.auth.views import LoginView
from django.shortcuts import render, redirect
from django.urls import reverse_lazy
from django.views.generic import CreateView

from .forms import RegisterUserForm, LoginUserForm


class RegisterUser(CreateView):
    form_class = RegisterUserForm
    success_url = reverse_lazy('login')
    template_name = 'users/register.html'

settings.py:

AUTH_USER_MODEL = 'users.CustomUser'

Answer 1

If you want to use only placeholder just remove the default value from model, since a value in a form takes presence over the placeholder.

If that is not an option then you can define an initial parameter in the form field

Here is an example:

class NewSomeModel(forms.ModelForm):
    title = forms.CharField(
        initial=None,
        widget=forms.TextInput(attrs={'placeholder': 'Myplaceholdertext'})
    )

    def clean_title(self):
        title = self.cleaned_data['title']
        return title or 'some-default-value-here'
    
    class Meta:
        model = SomeModel
        fields = ['title']