status code: 206 partial content

const express = require('express');
const app = express();

app.get('/file', (req, res) => {
  const { range } = req.headers;
  if (!range) {
    return res.status(416).send('Requires Range header');
  }

  const fileSize = 10000; // 假设文件大小为 10000 字节
  const parts = range.replace(/bytes=/, '').split('-');
  const start = parseInt(parts[0], 10);
  const end = parts[1] ? parseInt(parts[1], 10) : fileSize - 1;

  if (start >= fileSize || end >= fileSize) {
    return res.status(416).send('Range not satisfiable');
  }

  const chunkSize = (end - start) + 1;
  const fileData = Buffer.alloc(chunkSize); // 模拟文件数据

  res.status(206).header({
    'Content-Range': `bytes ${start}-${end}/${fileSize}`,
    'Accept-Ranges': 'bytes',
    'Content-Length': chunkSize,
    'Content-Type': 'application/octet-stream'
  }).send(fileData);
});

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