使用Django Rest Framework注册用户时触发TypeError报错求助

问题描述 #

我是Django和DRF新手，使用Postman注册新用户时遇到如下报错：

调用`User.objects.create()`时触发TypeError。这可能是因为你的序列化器类中有一个可写字段，它不是`User.objects.create()`的有效参数。你可能需要将该字段设为只读，或者重写UserRegistrationSerializer.create()方法来正确处理这个问题。

我跟随教程编写代码，但教程中的代码可正常运行，我却卡在此问题数小时，希望有人能解释报错原因。以下是我的代码：

serializers.py #

from rest_framework import serializers
from account.models import User

class UserRegistrationSerializer(serializers.ModelSerializer):
  password2 = serializers.CharField(style={'input_type':'password'},write_only=True)
  class  Meta:
    model =  User
    fields = ['email','name','password','password2','tc']
    extra_kwargs = {
      'password':{'write_only':True}
    }
    # validating Password and confirm password while Registration
    def validate(self,attrs):
      password = attrs.get('password')
      password2 = attrs.get('password2')
      if password != password2:
        raise serializers.ValidationError("Password and confirm password doesn't match")
      return attrs
    
    def create(self,validate_data):
      print(validate_data);
      return User.objects.create_user(**validate_data);

Models.py #

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

# Custom User Manager
class UserManager(BaseUserManager):
  def create_user(self, email, name,tc, password=None,password2=None):
      """
      Creates and saves a User with the given email, name, tc and password.
      """
      if not email:
          raise ValueError('Users must have an email address')

      user = self.model(
          email=self.normalize_email(email),
          name = name,
          tc = tc,
      )

      user.set_password(password)
      user.save(using=self._db)
      return user

  def create_superuser(self, email, name,tc, password=None):
      """
      Creates and saves a superuser with the given email, name, tc and password.
      """
      user = self.create_user(
          email,
          password=password,
          name=name,
          tc=tc,
      )
      user.is_admin = True
      user.save(using=self._db)
      return user
# Custom user model
class User(AbstractBaseUser):
  email = models.EmailField(
      verbose_name='Email',
      max_length=255,
      unique=True,
  )
  name = models.CharField(max_length=200)
  tc = models.BooleanField()
  is_active = models.BooleanField(default=True)
  is_admin = models.BooleanField(default=False)
  created_at = models.DateTimeField(auto_now_add=True)
  updated_at = models.DateTimeField(auto_now=True)
  
  objects = UserManager()

  USERNAME_FIELD = 'email'
  REQUIRED_FIELDS = ['name','tc']

  def __str__(self):
      return self.email

  def has_perm(self, perm, obj=None):
      "Does the user have a specific permission?"
      # Simplest possible answer: Yes, always
      return self.is_admin

  def has_module_perms(self, app_label):
      "Does the user have permissions to view the app `app_label`?"
      # Simplest possible answer: Yes, always
      return True

  @property
  def is_staff(self):
      "Is the user a member of staff?"
      # Simplest possible answer: All admins are staff
      return self.is_admin

views.py #

from rest_framework.response import Response
from rest_framework import status
from rest_framework.views import APIView
from account.serializers import UserRegistrationSerializer
class UserRegistrationView(APIView):
  def post(self,request,format=None):
    serializer = UserRegistrationSerializer( data = request.data);
    print("******************************************")
    print(request.data);
    if serializer.is_valid(raise_exception=True):
      user = serializer.save()
      return Response({'msg':'Registration Sucssess'},status=status.HTTP_201_CREATED)
    return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

报错原因分析 #

1. 缩进错误导致重写方法失效：你的validate和create方法被错误地缩进在Meta类内部，DRF无法识别这些重写方法，会默认调用ModelSerializer的create方法——该方法直接调用User.objects.create()，但password2不是User模型的字段，因此触发TypeError。
2. 无效参数传递：即使修正缩进，create方法中把包含password2的完整validate_data传给create_user也会有问题，因为create_user方法不需要password2参数（它仅用于前端验证，模型和创建逻辑都不需要这个字段）。

解决方案 #

步骤1：修正缩进并移除无效字段 #

修改serializers.py，将validate和create方法移到Meta类外部，并在create方法中移除password2字段：

from rest_framework import serializers
from account.models import User

class UserRegistrationSerializer(serializers.ModelSerializer):
    password2 = serializers.CharField(style={'input_type':'password'}, write_only=True)
    
    class Meta:
        model = User
        fields = ['email','name','password','password2','tc']
        extra_kwargs = {
            'password':{'write_only':True}
        }
    
    # 验证密码和确认密码是否一致
    def validate(self, attrs):
        password = attrs.get('password')
        password2 = attrs.get('password2')
        if password != password2:
            raise serializers.ValidationError("密码和确认密码不匹配")
        return attrs
    
    def create(self, validate_data):
        # 移除不需要的password2字段
        validate_data.pop('password2')
        return User.objects.create_user(**validate_data)

步骤2：验证逻辑 #

• validate方法已经完成了密码一致性校验，password2完成使命后无需再传入用户创建方法。
• 修正缩进后，DRF会使用你重写的create方法，而非默认逻辑，避免调用User.objects.create()时传入无效字段。

完成上述修改后，重新用Postman测试注册接口即可正常运行。

内容的提问来源于stack exchange，提问作者sushant aryal