如何在node.js中将url重定向到www？

const http = require('http');

const server = http.createServer((req, res) => {
  // 处理请求
});

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

const http = require('http');

const server = http.createServer((req, res) => {
  const { headers, url } = req;
  const host = headers.host;

  if (!host.startsWith('www.')) {
    const redirectUrl = `https://www.${host}${url}`;
    res.writeHead(301, { Location: redirectUrl });
    res.end();
  } else {
    // 处理其他请求
  }
});

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

const http = require('http');
const https = require('https');
const fs = require('fs');

const options = {
  key: fs.readFileSync('private-key.pem'),
  cert: fs.readFileSync('public-cert.pem')
};

const server = http.createServer((req, res) => {
  // HTTP重定向逻辑
});

const httpsServer = https.createServer(options, (req, res) => {
  // HTTPS请求处理逻辑
});

server.listen(80, () => {
  console.log('HTTP Server is running on port 80');
});

httpsServer.listen(443, () => {
  console.log('HTTPS Server is running on port 443');
});