同步多请求支付Express Node.js [英] Synchronization multi request payment express nodejs

问题描述

今天，我正在用猫鼬构建RESTful API充值资金.这包括增加和减少.我希望金额永远不会超过0.

Today I am building RESTful API recharge money with mongoose. This include increase and decrease. I want amount never get bellow than 0.

如果多个请求增加一个帐户，没问题.但我要求非常快速的多要求充值帐户坏了!!!!

No problem if multi request increase by one account. But I request very very fast multi request recharge a account It broken!!!!

这是一个减少帐户资金的示例:

This is a example decrease money of a account:

app.post("/recharge",function(req,res){
    Bottle.findById({user: "foo"}, function (err, user) {
    if(user.money <= 0) return res.json({message: "Not enough money"});
    else {
        user.money -=5000;
        user.save();
        return res.json({message: "Give success"});
        }    
    })
}

我设置了 foo 钱= 5000

然后在0.001秒内发出10个快速请求.然后我检查我的数据库，它显示fo money -25000

Then a make fast 10 request in 0.001s. Then I check my database It show fo money -25000

不是同步吗?

为什么 if(user.money< = 0)返回res.json({message:没有足够的钱"}); 无效?

请帮帮我.每个答案都会被接受！

Help me please. Every answer will be accepted!

推荐答案

使用方括号 {} 可能会有所帮助，并且您调用返回res.json({message:"Give成功}); 将在 user.save(); 完成之前完成.

It may help to use brackets {} and also your call to return res.json({message: "Give success"}); will complete BEFORE user.save(); is complete.

async-await 示例，省略了错误处理.

async-await example given below with error handling omitted.

app.post("/recharge", async (req,res) => {
    const user = await Bottle.findById({user: "foo"}).exec();

    if (user.money <= 0) {
        res.json({message: "Not enough money"});
        return;
    }

    user.money -= 5000;
    await user.save()

    res.json({message: "Give success"});
}

这篇关于同步多请求支付Express Node.js的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！