在我的 DRF 應用程式中，我有以下模型、序列化程式和視圖。
模型.py
class Log(models.Model):
plant = models.ForeignKey(Plant, on_delete=models.CASCADE)
date_time = models.DateTimeField()
water_consumption = models.PositiveSmallIntegerField()
elec_consumption = models.PositiveSmallIntegerField()
序列化程式.py
class ConsumptionSerializer(serializers.ModelSerializer):
class Meta:
model = Log
fields = ("water_consumption", "elec_consumption")
視圖.py
class ConsumptionViewSet(viewsets.ModelViewSet):
permission_classes = [permissions.IsAuthenticated, ]
serializer_class = ConsumptionSerializer
def get_queryset(self):
# Get params from url
start_date = self.request.query_params.get('start_date')
end_date = self.request.query_params.get('end_date')
# Make sure params are not null
if start_date is not None and end_date is not None:
queryset = queryset.filter(date_time__range=[start_date, end_date])
return queryset
else:
raise ValidationError({"ERROR": ["No params found in url"]})
這有效，它在 JSON 中輸出如下內容：
[
{
"water_consumption": 1,
"electrical_consumption": 1
},
{
"water_consumption": 1,
"electrical_consumption": 1
},
{
"water_consumption": 1,
"electrical_consumption": 1
},
]
我想要實作的是在這些資料旁邊接收一些聚合資料，如下所示：
{
"total_water_consumption": 3,
"total_elec_consumption": 3,
"detailed_logs": [{
"water_consumption": 1,
"electrical_consumption": 1
},
{
"water_consumption": 1,
"electrical_consumption": 1
},
{
"water_consumption": 1,
"electrical_consumption": 1
}]
}
我應該如何自定義查詢集以添加總值？
先感謝您。
uj5u.com熱心網友回復：
您可以SerializerMethodField在序列化程式檔案中使用它
檔案：https : //www.django-rest-framework.org/api-guide/fields/#serializermethodfield
您可以request在序列化程式中訪問為context：
from django.db.models import Sum
class ConsumptionSerializer(serializers.ModelSerializer):
total_water_consumption = serializers.SerializerMethodField()
total_elec_consumption = serializers.SerializerMethodField()
class Meta:
model = Log
fields = ("water_consumption", "elec_consumption")
def get_total_water_consumption(self, obj):
request = self.context['request']
query_params = request.query_params.get(...)
return Log.objects.filter(...).aggregate(Sum('water_consumption')).get('water_consumption__sum')
def get_total_elec_consumption(self, obj):
request = self.context['request']
query_params = request.query_params.get(...)
return Log.objects.filter(...).aggregate(Sum('elec_consumption')).get('elec_consumption__sum')
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