Django REST 框架："This field is required." 需要=False 和 unique_together

Question

我想用 Django REST Framework 保存一个简单的模型。唯一的要求是 UserVote.created_by 在 perform_create() 方法中自动设置。失败并出现以下异常：

{
    "created_by": [
        "This field is required."
    ]
}

我猜是因为 unique_together 索引。

models.py:

class UserVote(models.Model):
    created_by = models.ForeignKey(User, related_name='uservotes')
    rating = models.ForeignKey(Rating)

    class Meta:
        unique_together = ('created_by', 'rating')

serializers.py

class UserVoteSerializer(serializers.ModelSerializer):
    id = serializers.IntegerField(read_only=True)
    created_by = UserSerializer(read_only=True)

    class Meta:
        model = UserVote
        fields = ('id', 'rating', 'created_by')

views.py

class UserVoteViewSet(viewsets.ModelViewSet):
    queryset = UserVote.objects.all()
    serializer_class = UserVoteSerializer
    permission_classes = (IsCreatedByOrReadOnly, )

    def perform_create(self, serializer):
        serializer.save(created_by=self.request.user)

如何在 DRF 中保存我的模型而无需用户提供 created_by 而是在代码中自动设置此字段？

提前致谢！

Answer 1

我有一个类似的问题，我通过显式创建一个新实例并将其传递给序列化程序来解决它。在 UserVoteViewSet 中，您必须将 perform_create 替换为 create:

 def create(self, request, *args, **kwargs):
    uv = UserVote(created_by=self.request.user)
    serializer = self.serializer_class(uv, data=request.data)
    if serializer.is_valid():
        serializer.save()
        return Response(serializer.data, status=status.HTTP_201_CREATED)
    else:
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

Answer 2

另一种奇怪的方法是使用这样的信号

@receiver(pre_save, sender=UserVote)
def intercept_UserVote(sender, instance, *args, **kwargs):
    import inspect
    for frame_record in inspect.stack():
        if frame_record[3]=='get_response':
            request = frame_record[0].f_locals['request']
            break
    else:
        request = None

    instance.pre_save(request)

然后基本上你可以在你的模型中定义pre_save

def pre_save(self, request):
    # do some other stuff
    # Although it shouldn't happen but handle the case if request is None
    self.created_by = request.user

这个系统的优点是您可以为每个模型使用相同的代码。如果您需要更改任何内容，只需更改 pre_save()。您还可以添加更多内容

Answer 3

我在 views.py

中用一行代码解决了这个问题

def create(self, request, *args, **kwargs):
    request.data.update({'created_by': request.user.id})
    return super(UserVoteViewSet, self).create(request, *args, **kwargs)

由于此视图需要对用户进行身份验证，因此不要忘记为 rest_framework.permissions.IsAuthenticated

扩展 permission_classes

Answer 4

下面的代码对我有用。

即使我在多次实验后也遇到了同样的错误，所以在 class meta 中添加了 serializer.py 中的所有字段，如下所示 -

class Emp_UniSerializer( serializers.ModelSerializer ):
    class Meta:
        model = table
        fields = '__all__'  # To fetch For All Fields
        extra_kwargs = {'std_code': {'required': False},'uni_code': {'required': False},'last_name': {'required': False},'first_name': {'required': False}}

在这里，我们可以更新 "extra_kwargs" 中的任何字段，它不会显示错误 ["This field is required."]

Django REST 框架："This field is required." 需要=False 和 unique_together

Django REST Framework : "This field is required." with required=False and unique_together

python

database

django

unique

django-rest-framework