迁移服务平台秒杀

const express = require('express');
const app = express();
const bodyParser = require('body-parser');
const { Pool } = require('pg'); // PostgreSQL数据库连接池

app.use(bodyParser.json());

const pool = new Pool({
  user: 'your_db_user',
  host: 'your_db_host',
  database: 'your_db_name',
  password: 'your_db_password',
  port: 5432,
});

app.post('/seckill', async (req, res) => {
  const { productId, userId } = req.body;
  
  // 使用事务保证操作的原子性
  const client = await pool.connect();
  try {
    await client.query('BEGIN');
    
    // 检查库存
    const stockResult = await client.query('SELECT stock FROM products WHERE id = $1 FOR UPDATE', [productId]);
    if (stockResult.rows[0].stock <= 0) {
      return res.status(400).send('Out of stock');
    }
    
    // 扣减库存
    await client.query('UPDATE products SET stock = stock - 1 WHERE id = $1', [productId]);
    
    // 记录订单
    await client.query('INSERT INTO orders (product_id, user_id) VALUES ($1, $2)', [productId, userId]);
    
    await client.query('COMMIT');
    res.send('Seckill successful');
  } catch (e) {
    await client.query('ROLLBACK');
    throw e;
  } finally {
    client.release();
  }
});

app.listen(3000, () => console.log('Server running on port 3000'));