ValueError:不能分配"1"："LeadFacilityAssign.assigned_facilities“必须是”设施“实例

Question

我一直试图创建一个api端点来更新我的“铅”对象，并在发送put请求时向它们添加一个工具列表(每次都有不同数量的工具)。铅对象已经存在于数据库中，设施对象也是如此。由于我需要一个日期和时间与每个工具相关联，当它们被添加到一个领导时，我创建了"LeadFacilityAssign“类。由于我无法让它开始工作，所以我现在只想通过post请求来完成它，在领导创建过程中。有人告诉我，如果我需要以这种方式添加多个工具，我需要使用bulk_create。我在drf文档中找不到任何关于bulk_create的东西，所以我决定现在只使用一个工具来完成这个任务，并且每次只改进我的代码，因为我对drf很陌生。

有人知道是什么导致了这个错误吗？我尝试了几种不同的方法，但到目前为止都没有用。

ValueError: Cannot assign "1": "LeadFacilityAssign.assigned_facilities" must be a "Facility" instance.

serializers.py

class LeadUpdateSerializer(serializers.ModelSerializer):
    is_owner = serializers.SerializerMethodField()
    assigned_facilities = serializers.IntegerField(required=True)
    datetime = serializers.DateTimeField(required=True)

    class Meta:
        model = Lead
        fields = (
            "id",
            "first_name",
            "last_name",
            "assigned_facilities",
            "datetime",
        )
        read_only_fields = ("id", "created_at", "agent", "is_owner")

    def get_is_owner(self, obj):
        user = self.context["request"].user
        return obj.agent == user
    
    def create(self, validated_data):
        assigned_facilities = validated_data.pop("assigned_facilities")
        datetime = validated_data.pop("datetime")
        instance = Lead.objects.create(**validated_data)
        instance.leadfacility.create(assigned_facilities=assigned_facilities,datetime=datetime)
        print(instance)
        return instance

models.py

class Facility(models.Model):
    name = models.CharField(max_length=150, null=True, blank=False)

    def __str__(self):
        return self.name

class Lead(models.Model):
    first_name = models.CharField(max_length=40, null=True, blank=True)
    last_name = models.CharField(max_length=40, null=True, blank=True)

    def __str__(self):
        return f"{self.first_name} {self.last_name}"

class LeadFacilityAssign(models.Model):
    assigned_facilities = models.ForeignKey(Facility, on_delete=models.CASCADE, related_name='leadfacility')
    lead = models.ForeignKey(Lead, on_delete=models.CASCADE, related_name='leadfacility')
    datetime = models.DateTimeField()

views.py

class LeadCreateView(CreateAPIView):
    permission_classes = [IsAuthenticated, IsLeadOwner]
    serializer_class = LeadUpdateSerializer

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

class LeadUpdateView(UpdateAPIView):
    permission_classes = [IsAuthenticated, IsLeadOwner]
    serializer_class = LeadUpdateSerializer

    def get_queryset(self):
        return Lead.objects.all()

Answer 1

您正在尝试将Integer值添加到FK field中。

你有两个选择。您可以更改序列化程序字段。

assigned_facilities = serializers.PrimaryKeyRelatedField(queryset=Facility.objects.all(), required=True, write_only=True)

或

    assigned_facilities = serializers.IntegerField(required=True, write_only=True)
instance.leadfacility.create(assigned_facilities_id=assigned_facilities,datetime=datetime)

我宁愿使用1种选择。

Answer 2

另一种可能的解决方案是：

class LeadUpdateSerializer(serializers.ModelSerializer):
    is_owner = serializers.SerializerMethodField()
    assigned_facilities = serializers.IntegerField(required=True)
    datetime = serializers.DateTimeField(required=True)

    class Meta:
        model = Lead
        fields = (
            "id",
            "first_name",
            "last_name",
            "assigned_facilities",
            "datetime",
        )
        read_only_fields = ("id", "created_at", "agent", "is_owner")
   
    def validate_assigned_facility(self, facility_pk)->:
        assigned_facility = Facility.objects.filter(pk=facility_pk).first()
        if assigned_facility:
            return assigned_facility
        raise ValidationError('Facility not found, provide a valid pk')

    def get_is_owner(self, obj):
        user = self.context["request"].user
        return obj.agent == user
    
    def create(self, validated_data):
        assigned_facilities = validated_data.pop("assigned_facilities")
        datetime = validated_data.pop("datetime")
        instance = Lead.objects.create(**validated_data)
        instance.leadfacility.create(assigned_facilities=assigned_facilities,datetime=datetime)
        print(instance)
        return instance

这个解决方案很大，但非常灵活，因为您可以在模型或数据源中的输入和预期数据周围添加更多业务逻辑。