【Vue+Django REST framework实战】第9章—— 购物车、订单管理和支付功能

购物车功能需求分析和加入到购物车实现

#购物车url
router.register(r'shopcarts', ShoppingCartViewset, base_name="shopcarts")

class ShoppingCartViewset(viewsets.ModelViewSet):
    """
    购物车功能
    list:
        获取购物车详情
    create：
        加入购物车
    delete：
        删除购物记录
    """
    permission_classes = (IsAuthenticated, IsOwnerOrReadOnly)
    authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication)
    serializer_class = ShopCartSerializer
    lookup_field = "goods_id"

    def perform_create(self, serializer):
        shop_cart = serializer.save()
        goods = shop_cart.goods
        goods.goods_num -= shop_cart.nums
        goods.save()

    def perform_destroy(self, instance):
        goods = instance.goods
        goods.goods_num += instance.nums
        goods.save()
        instance.delete()

    def perform_update(self, serializer):
        existed_record = ShoppingCart.objects.get(id=serializer.instance.id)
        existed_nums = existed_record.nums
        saved_record = serializer.save()
        nums = saved_record.nums-existed_nums
        goods = saved_record.goods
        goods.goods_num -= nums
        goods.save()

    def get_serializer_class(self):
        if self.action == 'list':
            return ShopCartDetailSerializer
        else:
            return ShopCartSerializer

    def get_queryset(self):
        return ShoppingCart.objects.filter(user=self.request.user)

class ShopCartDetailSerializer(serializers.ModelSerializer):
    goods = GoodsSerializer(many=False, read_only=True)
    class Meta:
        model = ShoppingCart
        fields = ("goods", "nums")


class ShopCartSerializer(serializers.Serializer):
    user = serializers.HiddenField(
        default=serializers.CurrentUserDefault()
    )
    nums = serializers.IntegerField(required=True, label="数量",min_value=1,
                                    error_messages={
                                        "min_value":"商品数量不能小于一",
                                        "required": "请选择购买数量"
                                    })
    goods = serializers.PrimaryKeyRelatedField(required=True, queryset=Goods.objects.all())

    def create(self, validated_data):
        user = self.context["request"].user
        nums = validated_data["nums"]
        goods = validated_data["goods"]

        existed = ShoppingCart.objects.filter(user=user, goods=goods)

        if existed:
            existed = existed[0]
            existed.nums += nums
            existed.save()
        else:
            existed = ShoppingCart.objects.create(**validated_data)

        return existed

    def update(self, instance, validated_data):
        #修改商品数量
        instance.nums = validated_data["nums"]
        instance.save()
        return instance