Django实战-生鲜电商-提交订单

# 创建事务保存点
        save_id = transaction.savepoint()
        try:
            order = OrderInfo.objects.create(
                order_id=order_id,
                user=user,
                address=address,
                total_amount=0,
                trans_cost=10,
                pay_method=pay_method,
            )

# 回退的保存点的状态
transaction.savepoint_rollback(save_id)

class CommitOrderView(LoginRequiredJsonMixin, TransactionAtomicMixin, View):
    """提交订单"""
    def post(self, request):
        # 获取参数
        #  user 地址id  支付方式  商品id  数量(从购物车中获取）
        user = request.user
        address_id = request.POST.get("address_id")
        sku_ids = request.POST.get("sku_ids")  # "1,2,3,4"
        pay_method = request.POST.get("pay_method")

        # 校验参数
        if not all([address_id, sku_ids, pay_method]):
            return JsonResponse({"code": 2, "message": "参数缺失"})

        # 判断地址是否存在
        try:
            address = Address.objects.get(id=address_id)
        except Address.DoesNotExist:
            return JsonResponse({"code": 3, "message": "地址不存在"})

        # 判断支付方式
        pay_method = int(pay_method)
        if pay_method not in OrderInfo.PAY_METHODS.keys():
            return JsonResponse({"code": 4, "message": "支付方式错误"})

        # 判断商品
        sku_ids = sku_ids.split(",")   # ["1", "2"]
        redis_conn = get_redis_connection("default")
        cart = redis_conn.hgetall("cart_%s" % user.id)

        # 创建一个订单基本信息表数据

        # 自定义的order_id  "20171026111111用户id"
        order_id = timezone.now().strftime("%Y%m%d%H%M%S") + str(user.id)

        # 创建事务保存点
        save_id = transaction.savepoint()
        try:
            order = OrderInfo.objects.create(
                order_id=order_id,
                user=user,
                address=address,
                total_amount=0,
                trans_cost=10,
                pay_method=pay_method,
            )

            total_count = 0  # 总数
            total_amount = 0  # 总金额
            for sku_id in sku_ids:
                for i in range(3):
                    try:
                        sku = GoodsSKU.objects.get(id=sku_id)
                    except GoodsSKU.DoesNotExist:
                        # 回退的保存点的状态
                        transaction.savepoint_rollback(save_id)
                        return JsonResponse({"code": 5, "message": "商品有误"})

                    # 获取订购的商品数量，判断库存
                    sku_count = cart.get(sku_id.encode())
                    sku_count = int(sku_count)
                    if sku_count > sku.stock:
                        # 回退的保存点的状态
                        transaction.savepoint_rollback(save_id)
                        return JsonResponse({"code": 6, "message": "库存不足"})

                    # 减少商品的库存, 增加商品的销量
                    origin_stock = sku.stock
                    new_stock = origin_stock - sku_count
                    new_sales = sku.sales + sku_count
                    # update操作会返回受影响的行数，即更新成功的函数
                    result = GoodsSKU.objects.filter(id=sku_id, stock=origin_stock).update(stock=new_stock, sales=new_sales)
                    if result == 0 and i < 2:
                        # 表示更新失败
                        continue
                    elif result == 0 and i == 2:
                        # 表示尝试三次失败
                        transaction.savepoint_rollback(save_id)
                        return JsonResponse({"code": 7, "message": "下单失败"})

                    # 保存订单商品
                    OrderGoods.objects.create(
                        order=order,
                        sku=sku,
                        count=sku_count,
                        price=sku.price,
                    )

                    # 累计计算总数
                    total_count += sku_count
                    # 累计计算总金额
                    total_amount += (sku.price * sku_count)

                    # 跳出三次循环，处理下一个商品
                    break

            # 修改订单基本信息表中的统计数据字段
            order.total_count = total_count
            order.total_amount = total_amount + 10
            order.save()

        except Exception:
            # 出现任何异常，都要回退的保存点的状态
            transaction.savepoint_rollback(save_id)
            return JsonResponse({"code": 8, "message": "下单失败"})

        # 执行成功，提交事务
        transaction.savepoint_commit(save_id)

        # 保存最新的购物车数据
        redis_conn.hdel("cart_%s" % user.id, *sku_ids)  # 删除订购的商品

        # 返回前端json状态
        return JsonResponse({"code": 0, "message": "创建订单成功"})