REST 框架——序列化多对多。创建并保存

Question

我正在为我的 API 使用 django-restframework。

我的问题：我无法验证数据。需要创建“区域”并与 courier 嵌套。区域作为 json 列表发送。

但在验证数据时，出现以下错误： error_valid {'regions': [{'non_field_errors': [ErrorDetail(string='Invalid data. Expected a dictionary, but got int.', code='invalid')]}, {'non_field_errors': [ErrorDetail(string='Invalid data. Expected a dictionary, but got int.', code='invalid')]}, {'non_field_errors': [ErrorDetail(string='Invalid data. Expected a dictionary, but got int.', code='invalid')]

如何使用这个 json POST 请求创建模型？

POST json：

{
"data": [
{
"courier_id": 10,
"courier_type": "foot",
"regions": [1, 12, 22]
},
{
"courier_id": 11,
"courier_type": "bike",
"regions": [22]
},..
]
}

我的models.py：

class Regions(models.Model):
    region_id = models.PositiveIntegerField(unique=True)

    def __str__(self):
        return self.region_id


class Courier(models.Model):
    courier_id = models.PositiveIntegerField(unique=True,
                                             )
    courier_type = models.CharField(max_length=4,
                                    choices=TypeCourier.choices,
                                    blank=False,
                                    )
    regions = models.ManyToManyField("Regions",
                                     through=RegionsCouriers,
                                     through_fields=("courier",
                                                     "region"
                                                     ),
                                     )

需要与发布请求一起创建区域 我的序列化器.py

class RegionsSerializer(serializers.ModelSerializer):

    class Meta:
        fields = "__all__"
        model = Regions


class CourierSerializerPost(serializers.ModelSerializer):
    regions = RegionsSerrializer(many=True)

    class Meta:
        model = Courier
        fields = "__all__"

我的视图.py

class CourierView(APIView):

    def post(self, request):
        data = request.data["data"]
        couriers_add = []
        couriers_fail = []
        for record in data:
            serializer = CourierSerializerPost(data=record)
            if serializer.is_valid():
                courier_id = record["courier_id"]
                couriers_add.append({"id": courier_id})
                serializer.save()
            else:
                couriers_fail.append({"id": record["courier_id"]})
        if couriers_fail:
            return Response({"couriers": couriers_fail},
                        status=status.HTTP_400_BAD_REQUEST)
        else:
            return Response({"couriers": couriers_add},
                            status=status.HTTP_201_CREATED
                            )

请帮帮我 升级版： 我如何将验证区域字段更改为列表正整数字段。 我的错误：我无法创建： record {'courier_id': 12, 'courier_type': 'car', 'regions': [12, 22, 23, 33]}

serializer.is_valid False

serializer.error {'regions': [{'non_field_errors': [ErrorDetail(string='Invalid data. Expected a dictionary, but got int.', code='invalid')]},

Answer 1

您不能像使用外键或一对一那样使用序列化程序来保存 M2M 字段。

你需要重写序列化器的create方法并指定M2M添加

class CourierSerializerPost(serializers.ModelSerializer):
    regions = RegionsSerrializer(many=True)

    class Meta:
        model = Courier
        fields = "__all__"

    def create(self, validated_data):
        # removing the regions ids from the about to be created Courier obj
        regions_ids = validated_data.pop('regions', None)
        # getting the regions objs
        regions = tuple(Regions.objects.filter(id__in=regions_ids))
        # creating the Courier object
        obj = Courier.objects.create(**validated_data)
        # adding the regions relations to it
        obj.regions.add(*regions)
        return obj