用户访问管理秒杀

const express = require('express');
const redis = require('redis');
const app = express();
const client = redis.createClient();

app.use(express.json());

app.post('/seckill', async (req, res) => {
  const { productId, userId } = req.body;
  
  // 使用Redis的Lua脚本来保证操作的原子性
  const luaScript = `
    local stock = tonumber(redis.call('get', KEYS[1]))
    if stock and stock > 0 then
      redis.call('decr', KEYS[1])
      return 1
    else
      return 0
    end
  `;
  
  try {
    const result = await new Promise((resolve, reject) => {
      client.eval(luaScript, 1, `stock:${productId}`, (err, reply) => {
        if (err) reject(err);
        else resolve(reply);
      });
    });
    
    if (result === 1) {
      res.status(200).send({ message: '秒杀成功' });
    } else {
      res.status(400).send({ message: '秒杀失败，库存不足' });
    }
  } catch (error) {
    res.status(500).send({ message: '服务器错误' });
  }
});

app.listen(3000, () => {
  console.log('秒杀服务启动，监听端口3000');
});