Django自定义UserCreationForm无法从forms.py导入views.py如何解决

问题根因 #

你的UserRegisterForm无法导入的核心问题是forms.py存在缩进错误：UserRegisterForm被错误嵌套写在了UserLoginForm类的内部，不属于模块顶层可直接导入的成员，而同层级的UserLoginForm本身是顶层类，所以可以正常导入。

同时你的代码还存在另外两处会导致运行报错的问题：

• UserCreationForm内置的密码字段为password1（输入密码）、password2（确认密码），你表单Meta中声明的password字段不存在
• 注册视图中password = form.save(commit=False)写法错误，save(commit=False)返回的是用户对象，无法直接获取密码

修正后的forms.py代码 #

from django import forms
from django.contrib.auth import authenticate
from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth.models import User


class UserLoginForm(forms.Form):
    username = forms.CharField()
    password = forms.CharField(widget=forms.PasswordInput)

    def clean(self, *args, **kwargs):
        username = self.cleaned_data.get('username')
        password = self.cleaned_data.get('password')

        if username and password:
            user = authenticate(username=username, password=password)

            if not user:
                raise forms.ValidationError('This user does not exist')
            if not user.check_password(password):
                raise forms.ValidationError('Incorrect password')
            if not user.is_active:
                raise forms.ValidationError('This user is not active')
        return super(UserLoginForm, self).clean(*args, **kwargs)

# 缩进拉到和UserLoginForm同级，成为模块顶层类
class UserRegisterForm(UserCreationForm):
    email = forms.EmailField(label='Email address')
    email2 = forms.EmailField(label='Confirm email')

    class Meta:
        model = User
        fields = [
            'username',
            'email',
            'email2',
            'password1', # 替换为UserCreationForm内置的密码字段
            'password2'
        ]

    # 改为全局clean方法，才能同时获取两个邮箱字段做校验
    def clean(self):
        cleaned_data = super().clean()
        email = cleaned_data.get('email')
        email2 = cleaned_data.get('email2')
        if email != email2:
            raise forms.ValidationError("emails must match")
        email_qs = User.objects.filter(email=email)
        if email_qs.exists():
            raise forms.ValidationError(
                "This email is already being used"
            )
        return cleaned_data

修正后的注册视图代码 #

def register_view(request):
    next = request.GET.get('next')
    form = UserRegisterForm(request.POST or None)
    if form.is_valid():
        user = form.save(commit=False)
        # UserCreationForm会自动处理密码加密，直接保存即可
        user.save()
        new_user = authenticate(username=user.username, password=form.cleaned_data.get('password1'))
        login(request, new_user)
        if next:
            return redirect(next)
        return redirect('/')

    context = {
        'form': form,
    }

    return render(request, 'signup.html', context)

修正后即可正常导入UserRegisterForm，注册功能也能正常运行。

内容的提问来源于stack exchange，提问作者Jie-Liang Lin