Queryset 返回响应自定义

Question

我对 Django restframework 很陌生，我现在正在尝试使用外键返回对象。

class User(models.Model):
    name = models.CharField(max_length=255,blank=True)
    date_created = models.DateTimeField(auto_now_add=True)
    date_modiefied = models.DateTimeField(auto_now=True)
    area = models.CharField(max_length=255,blank=True)
    uuid = models.CharField(max_length=255)
    home = models.CharField(max_length=255,blank=True)
    work = models.CharField(max_length=255,blank=True)
    mobileNo = models.CharField(max_length=255,blank=True)
    email = models.CharField(max_length=255,blank=True)
    appVersionCode = models.CharField(max_length=255,blank=True)
    photoUrl = models.CharField(max_length=255,blank=True)
    serverTime = models.CharField(max_length=255,blank=True)
    fcmTokenId = models.CharField(max_length=255,blank=True)
   def __str__(self):
    return self.name

class LocationData(models.Model):
   user = models.ForeignKey(
     User, related_name='user', on_delete=models.DO_NOTHING)
    source_id = models.CharField(max_length=255)
    latitude = models.CharField(max_length=255)
    longitude = models.CharField(max_length=255)
    speed = models.CharField(max_length=255)
    kms = models.CharField(max_length=255)
    date_created = models.DateTimeField(auto_now=True)
    date_modiefied = models.DateTimeField(auto



class UserSerializer(serializers.ModelSerializer):
  class Meta:
    model = User
    fields = '__all__'

class LocationDataSerializer(serializers.ModelSerializer): 

class Meta:
    model = LocationData
    fields = '__all__'
    depth = 1

我正在使用 def get_queryset(self):

class SyncIndexLastDataViewSet(viewsets.ModelViewSet):
serializer_class = LocationDataSerializer

def get_queryset(self):

    userid = self.request.query_params.get('user_id', None)
    userExist = User.objects.filter(id=userid)
    if userExist.exists():
        # call the original 'list' to get the original response
        queryset = LocationData.objects.values('source_id').filter(user__id=userid).order_by('-source_id')[:1]
        lastSourceId = queryset[0]['source_id']
        response = {"collection": {"data": lastSourceId,"statusCode": status.HTTP_200_OK,"version":"1.0"}}
        json = JSONRenderer().render(response)
        # customize the response data
        if response is not None:
            return json
    else:
        # return response with this custom representation
        response = {"collection": {"data": "","statusCode":status.HTTP_404_NOT_FOUND,"version":"1.0","error":"Not found"}}
        return response

现在结果在下面的响应中，并立即抛出此错误

但我希望该查询集返回如下，因此我可以在 android 中读取这些密钥对值

{ "collection": {
  "data": {
    "id": 31,
    "source_id": "55",
    "latitude": "24654",
    "longitude": "454654",     
    "date_created": "2019-02-08T17:10:09.318644Z",
    "date_modiefied": "2019-02-08T17:10:09.318714Z",
    "area": "54546",
    "user": {
        "id": 1,
        "name": "Dormy",
        "date_created": "1992-01-18T03:29:53.388000Z",
        "date_modiefied": "2018-02-19T05:17:00.164000Z",
        "serverTime": "",
        "fcmTokenId": ""
      }
  },
    "statusCode": 200,
    "version": "1.0"
 }

现在错误抛出

AttributeError: 在尝试获取source_idserializer 上的字段值时出现 AttributeError LocationDataSerializer。序列化器字段可能命名不正确，并且与int实例上的任何属性或键都不匹配。原始异常文本为：'int' 对象没有属性 'source_id'。

谢谢！

Answer 1

对此的答案取决于您使用的视图类型，但最重要的是您不会这样做，因为get_queryset您在请求类型的方法中执行此操作。

因为如果你使用的是例如RetrieveAPIView应覆盖retrieve从方法RetrieveModelMixin像这样：

class MyAPIView(RetrieveAPIView):
    queryset = MyModel.objects.all()
    serializer_class = MySerializer

    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance)
        data = {
            "collection": {
                "data": serializer.data
            },
            "statusCode": 200,
            "version": "1.0"
        }
        return Response(data)

如果您使用的是 ListAPIView 之类的其他东西，那么您希望查看相关方法中使用的内容并覆盖它以包装您的数据。

这里要意识到的主要事情是它与获取查询集无关 - 这只是从数据库中获取数据。这是关于在发回响应时将数据转换为正确的格式。因此，工作应该在做出响应时完成。