不用cdn视频怎么加速

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

const server = http.createServer((req, res) => {
  const filePath = path.join(__dirname, 'video.mp4');
  const fileSize = fs.statSync(filePath).size;
  const chunkSize = 1024 * 1024; // 1MB
  let offset = 0;

  const readStream = fs.createReadStream(filePath, { start: offset, end: offset + chunkSize - 1 });

  readStream.on('data', (chunk) => {
    res.write(chunk);
  });

  readStream.on('end', () => {
    res.end();
  });

  readStream.on('error', (err) => {
    res.statusCode = 500;
    res.end(err.message);
  });
});

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