Django REST to_representation：序列化器字段最后出现

Question

我有以下序列化程序 class：

class DataLocationSerializer(QueryFieldsMixin, serializers.ModelSerializer):

    def create(self, validated_data):
        pass

    def update(self, instance, validated_data):
        pass

    class Meta:
        model = MeasurementsBasic
        fields = ['temp', 'hum', 'pres', 'co', 'no2',
                            'o3', 'so2']

    def to_representation(self, instance):
        representation = super().to_representation(instance)
        representation['timestamp'] = instance.time_received

        return representation

数据在 JSON 文件中返回，其结构如下：

{
    "source": "ST",
    "stations": [
        {
            "station": "ST1",
            "data": [
                {
                    "temp": -1.0,
                    "hum": -1.0,
                    "pres": -1.0,
                    "co": -1.0,
                    "no2": -1.0,
                    "o3": -1.0,
                    "so2": null,
                    "timestamp": "2021-07-04T21:00:03"                  
                }
            ]
        }
    ]
}

我怎样才能使时间戳出现在序列化程序的字段之前？

Answer 1

创建一个新字典：

def to_representation(self, instance):
    representation = super().to_representation(instance)
    return {'timestamp': instance.time_received, **representation }