如何从 ModelViewSet 中另一个对象的 PK 访问一个对象

Question

模型的通用结构是有教师和设备，每个设备与教师ID/PK都有一个ForeignKey关系。

我正在尝试以这样一种方式创建我的 API，即当转到教师的详细视图时，所有关联的设备都会显示出来。我已覆盖 get_serializer_class() 以指定在适当的时间使用哪个序列化程序，但无法弄清楚如何根据详细视图正确更改查询集.错误贴在下面。

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

class TeacherViewSet(viewsets.ModelViewSet):
    queryset = Teacher.objects.order_by('campus','name')
    serializer_class = TeacherSerializer
    detail_serializer_class = DeviceSerializer

    def get_serializer_class(self):
        if self.action == 'retrieve':
            if hasattr(self, 'detail_serializer_class'):
                return self.detail_serializer_class
        return super(TeacherViewSet, self).get_serializer_class()

    def get_queryset(self, pk=None):
        if pk is not None:
            return Device.objects.filter(device__owner=self.kwargs.get('pk')
        return Teacher.objects.all()

Answer 1

我能够通过在我的 TeacherSerializer 中添加一个嵌套的 DeviceSerializer 来解析设备对象列表，从而获得所需的输出。

class TeacherSerializer(serializers.ModelSerializer):
devices = DeviceSerializer(many=True)

class Meta:
    model = Teacher
    fields = ('id', 'name', 'campus', 'email', 'devices')

Answer 2

我假设您正在使用 DRF。如果是这种情况，只需将 TeacherSerializer 调整为：

def TeachSearializer(serializer.ModelSerializer):
    devices = serializers.SerializerMethodField()

    class Meta:
        model = Teacher
        fields = '__all__'

    def get_devices(self, obj):
        return Devices.objects.filter(teacher=obj)

就是这样，每次您在教师对象上使用序列化程序时，他们的设备都会添加到字段devices