python - AttributeError - 使用 Django NestedFields 序列化器时

Question

我有 2 个型号:-

class Users(models.Model):
    first_name = models.CharField(max_length=255)
    middle_name = models.CharField(max_length=255)


class UserAddress(models.Model):
    line1 = models.CharField(max_length=255)
    country = models.CharField(max_length=255)
    user = models.ForeignKey(Users)

用户模型和用户地址模型。以下是 2 个序列化器。

class UserAddressSerializer(ModelSerializer):

    class Meta:
        model = UserAddress
        exclude = ('id', 'user')


class UserSerializer(ModelSerializer):
    address = UserAddressSerializer(many=True)

    class Meta:
        model = Users
        fields = '__all__'

    def create(self, validated_data):
        address = validated_data.pop('address', [])
        user = Users.objects.create(**validated_data)

        for ad in address:
            UserAddress.objects.create(user=user, **ad)

        return user

我从客户端收到的数据是

{
  "first_name": "string",
  "last_name": "string",
  "address": [{
     "line1": "asd",
     "country": "asd",
  }],
}

这就是我创建新用户及其相应地址的方法。

class UserCreate(GenericAPIView):

    serializer_class = UserSerializer

    def post(self, request, *args, **kwargs):

        data = request.data
        serializer = UserSerializer(data=data)
        if not serializer.is_valid():
            return

        user = serializer.save()
        response = {
            'user_id': user.uuid
        }
        return

现在，在取回用户详细信息后，我收到一条错误消息

AttributeError: Got AttributeError when attempting to get a value for field `address` on serializer `UserSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `Users` instance.
Original exception text was: 'Users' object has no attribute 'address'.

这就是我获取用户详细信息(包括地址)的方法。

class UserDetails(GenericAPIView):
    queryset = Users.objects.all()
    serializer_class = UserSerializer
    lookup_field = 'uuid'

    def get(self, request, uuid, *args, **kwargs):
        user = Users.get_user(uuid)
        if not user:
            return 

        serializer = UserSerializer(instance=user)
        return

我读过this example嵌套关系，并且我正在以完全相同的方式进行。为什么会出现错误？

此外，可以使用一些 DRF mixin 来进一步缩短此代码(以更干净的方式)吗？如果是，那么如何？

Answer 1

我认为适合您的情况的最简单的解决方案是:在模型 UserAddress 中添加 lated_name='address'

class UserAddress(models.Model):
    line1 = models.CharField(max_length=255)
    country = models.CharField(max_length=255)
    user = models.ForeignKey(Users, related_name='address')
    #                                 ^^^^^^^^^^^^^^^

或者您可以在序列化程序中添加源属性:

class UserSerializer(ModelSerializer):
    address = UserAddressSerializer(source='useraddress_set', many=True)

序列化器尝试在模型User中查找属性“address”，但默认情况下它是模型名称下划线集(在您的情况下是useraddress_set)，并且您尝试其他名称，因此您可以在模型中设置或通过源指定。

在示例中您可以查看 models并找到lated_name='tracks'