如何将通过 POST 方法传递的参数与 Django rest 框架 Model 进行比较并生成自定义响应？

Question

I am designing Basic Django rest framework based application, i need to compare external parameters passed through POST method in Postman with Coupon code in database and generate custom response like 'This code is redeemed/validate." or " This is invalid coupon/code."

Here is my Model.py file:

from django.db import models
from django.core.validators import MinValueValidator, MaxValueValidator


class Coupon(models.Model):
    code = models.CharField(max_length=50, unique=True)
    valid_from = models.DateTimeField()
    valid_to = models.DateTimeField()
    discount = models.IntegerField(validators=[MinValueValidator(0), MaxValueValidator(100)])
    active = models.BooleanField()

    def __str__(self):
        return self.code

here is my views.py file:

from rest_framework import status
from rest_framework.decorators import api_view
from rest_framework.response import Response
from .models import Coupon
from .serializers import CouponSerializer
from rest_framework import viewsets

class CouponViewSet(viewsets.ModelViewSet):
    queryset = Coupon.objects.all()
    serializer_class = CouponSerializer


    @api_view(['POST'])
    def coupon_redeem(request):
        if request.method =='POST':
            serializer = CouponSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_200_OK)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

here is my Serializer.py file

from rest_framework import serializers
from .models import Coupon


class CouponSerializer(serializers.ModelSerializer):
    class Meta:
        model = Coupon
        fields = '__all__'

Please help if possible, Thank you.

Answer 1

IN Your post method u can filter the desired object like:

if serializer.is_valid():

    coup=Coupon.objects.filter(code=serializer.data['code'],active=True).exists()
    if(coup=="NULL"):
        return Response("This is invalid coupon/code",status=status.HTTP_400_BAD_REQUEST)
    else:
        return Response("This is valid code",status=status.HTTP_200_OK)