应用PaaS平台限时秒杀

const express = require('express');
const app = express();
const bodyParser = require('body-parser');
const { Pool } = require('pg');

const pool = new Pool({
  connectionString: 'your_database_url'
});

app.use(bodyParser.json());

app.post('/seckill', async (req, res) => {
  const { productId, userId } = req.body;
  const client = await pool.connect();
  try {
    await client.query('BEGIN');
    const result = await client.query('SELECT stock FROM products WHERE id = $1 FOR UPDATE', [productId]);
    if (result.rows[0].stock > 0) {
      await client.query('UPDATE products SET stock = stock - 1 WHERE id = $1', [productId]);
      await client.query('INSERT INTO orders (product_id, user_id) VALUES ($1, $2)', [productId, userId]);
      await client.query('COMMIT');
      res.status(200).send('秒杀成功');
    } else {
      await client.query('ROLLBACK');
      res.status(400).send('库存不足');
    }
  } catch (e) {
    await client.query('ROLLBACK');
    res.status(500).send('服务器错误');
  } finally {
    client.release();
  }
});

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