node.js 抢红包程序

const express = require('express');
const app = express();
const bodyParser = require('body - parser');
const redis = require('redis');
const client = redis.createClient();

app.use(bodyParser.json());

// 创建红包（简化示例）
app.post('/createRedPacket', (req, res) => {
    const { totalAmount, totalNum } = req.body;
    client.set('redPacketTotalAmount', totalAmount);
    client.set('redPacketTotalNum', totalNum);
    client.set('redPacketRemainAmount', totalAmount);
    client.set('redPacketRemainNum', totalNum);
    res.send('红包创建成功');
});

// 抢红包
app.post('/grabRedPacket', (req, res) => {
    const userId = req.body.userId;
    client.get('redPacketRemainNum', (err, remainNum) => {
        if (err) {
            return res.status(500).send('服务器错误');
        }
        if (remainNum <= 0) {
            return res.send('红包已被抢光');
        }
        client.get('redPacketRemainAmount', (err, remainAmount) => {
            if (err) {
                return res.status(500).send('服务器错误');
            }
            const amount = calculateRedPacketAmount(parseFloat(remainAmount), parseInt(remainNum), 1);
            client.decr('redPacketRemainNum');
            client.decrByFloat('redPacketRemainAmount', amount);
            // 这里可以将用户抢到红包的信息记录到数据库
            res.send(`恭喜您抢到${amount}元红包`);
        });
    });
});

function calculateRedPacketAmount(totalAmount, totalNum, num) {
    let remainAmount = totalAmount;
    let remainNum = totalNum;
    let amount = 0.01 * Math.floor(Math.random() * (remainAmount / remainNum * 100));
    amount = Math.max(amount, 0.01);
    amount = Math.min(amount, remainAmount - 0.01 * (remainNum - num - 1));
    return amount.toFixed(2);
}

app.listen(3000, () => {
    console.log('服务器运行在端口3000');
});