python - 如何在同一api内的django rest框架中获取聚合

Question

这是我的模型.py

from __future__ import unicode_literals
from django.db import models

class User(models.Model):
    name = models.CharField(max_length=200)
    company_name = models.ForeignKey('Company',on_delete=models.CASCADE,related_name='user')

    def __str__(self):
        return self.name

class Company(models.Model):
    name = models.CharField(max_length=200)
    phone_number = models.IntegerField(null=True,blank=True)

    def __str__(self):
        return self.name

class Catalog(models.Model):
    name = models.CharField(max_length=200)
    no_of_pcs = models.IntegerField(null=True,blank=True)
    per_piece_price = models.DecimalField(null=True,blank=True,max_digits=10,decimal_places=2)
    company_name = models.ForeignKey(Company,on_delete=models.CASCADE,related_name='catalog')

    def __str__(self):
        return self.name

这是我的serializers.py

from rest_framework import serializers
from .models import *
from django.db.models import Sum,Avg,Max,Min,Count,F,Q

class CatalogSerializer(serializers.HyperlinkedModelSerializer):
    dynamic_data = serializers.SerializerMethodField()
    class Meta:
        model = Catalog
        fields = '__all__'

    def get_dynamic_data(self, obj):
        totalpieces = Catalog.objects.all().aggregate(total_pieces=Count('no_of_pcs'))
        totalprice = Catalog.objects.all().aggregate(total_price=Sum('per_piece_price'))
        print(totalpieces["total_pieces"],totalprice["total_price"])
        return totalpieces["total_pieces"],totalprice["total_price"]


class UserSerializer(serializers.ModelSerializer):
    # name = serializers.StringRelatedField()
    company_name = serializers.CharField()
    class Meta:
        model = User
        fields = '__all__'

class CatalogData(serializers.ModelSerializer):
    class Meta:
        model = Catalog
        fields = ('name', 'no_of_pcs', 'per_piece_price')


class CompanySerializer(serializers.ModelSerializer):
    # catalog_details = serializers.SerializerMethodField()
    # name = serializers.StringRelatedField()
    catalog = CatalogData(many=True)
    user = UserSerializer(many=True)
    class Meta:
        model = Company
        fields = ('name', 'phone_number', 'catalog','user')

这是我的views.py

from __future__ import unicode_literals
from django.http import HttpResponse
from .models import *
import json
from django.http import JsonResponse, HttpResponse
from .serializers import *
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status
from rest_framework import viewsets


class CatalogView(viewsets.ModelViewSet):
    queryset =  Catalog.objects.select_related('company_name')
    serializer_class = CatalogSerializer


class CompanyView(viewsets.ModelViewSet):
    queryset =  Company.objects.all()
    serializer_class = CompanySerializer

class UserView(viewsets.ModelViewSet):
    queryset =  User.objects.all()
    serializer_class = UserSerializer

我正在获取这样的 api..

[
    {
        "url": "http://127.0.0.1:8000/catalogs/1/",
        "dynamic_data": [
            3,
            471118.0
        ],
        "name": "sarees",
        "no_of_pcs": 23,
        "per_piece_price": "33333.00",
        "company_name": "http://127.0.0.1:8000/companies/1/"
    }
]

这里的动态数据3是total no of pieces意思是aggregate Count而在动态数据中471118.0是总价表示聚合Sum

但我期待不同格式的 api

像这样:

[
    {
        "url": "http://127.0.0.1:8000/catalogs/1/",
        "total_pieces":3,
        "total_price": 471118.0
        "name": "sarees",
        "no_of_pcs": 23,
        "per_piece_price": "33333.00",
        "company_name": "http://127.0.0.1:8000/companies/1/"
    }
]

我想在同一个 api 中获得 total_pieces 和 total_price。

谢谢,,

Answer 1

在一个函数中你返回两个值，所以 django 不会把它分开并将它作为一个列表传递，如果你想要不同的键值对使用这个

class CatalogSerializer(serializers.HyperlinkedModelSerializer):
    total_pieces = serializers.SerializerMethodField()
    total_price = serializers.SerializerMethodField()
    class Meta:
        model = Catalog
        fields = '__all__'

    def get_total_pieces(self, obj):
        totalpieces = Catalog.objects.all().aggregate(total_pieces=Count('no_of_pcs'))
        return totalpieces["total_pieces"]
    def get_total_price(self, obj):
        totalprice = Catalog.objects.all().aggregate(total_price=Sum('per_piece_price'))
        return totalprice["total_price"]