python - 如何使用 Django REST Framework 读取数据、应用函数并返回结果？

Question

考虑一个计算“y = ax + b”的简单任务，其中“a”和“b”由模型给出，“x”由用户通过 API 请求给出，例如 http://someurl .com/api/15，其中 x=15。

通常，API 会以 JSON 格式返回“a”和“b”。但是，相反，我想在服务器上求解这个方程并且只返回“y”。但是，我不知道如何从 URL 获取“x”以及将最后一个函数放置在哪里以将“y”返回到 JSON。有什么想法吗？

模型.py:

from django.db import models

class SimpleEquation(models.Model):
    a = models.IntegerField()
    b = models.IntegerField()

序列化器.py:

from rest_framework import serializers
from .models import SimpleEquation

class SimpleEquationSerializer(serializers.ModelSerializer):
    class Meta:
        model = SimpleEquation
        fields = ('a','b') # Should return 'y' instead

views.py:

from rest_framework import generics
from .serializers import SimpleEquationSerializer

class Results(generics.ListAPIView):
    queryset = SimpleEquation.objects.all()[0]
    serializer_class = SimpleEquationSerializer

到目前为止我的愚蠢功能:

def the_function(request):
    x = SOME_REQUEST_GET_METHOD
    pars = SimpleEquation.objects.all()[0]
    a = pars.a
    b = pars.b
    y = a*x + b
    return y

Answer 1

使用Serializer Method Field

from rest_framework import serializers
from .models import SimpleEquation

class SimpleEquationSerializer(serializers.ModelSerializer):

    y = serializers.SerializerMethodField('get_y')

    class Meta:
        model = SimpleEquation
        fields = ('y')

    def get_y(self, obj):
        x =  self.context['request'].x
        y = obj.a*x + obj.b  # obj comes from the queryset from view
        return y