Send video chunk by chunk

send-video-express.js

if (!req.headers.range) {
  res.sendFile(fileAbsolutePath, { maxAge: '2 days' }, (err) => {
    if (err) console.error(err);
  });
} else {
  const { size, blksize } = statSync(fileAbsolutePath);

  const chunkSizeTarget = 10 ** 7 / 2;
  const chunkSize = Math.floor(chunkSizeTarget / blksize) * blksize;

  const start = Number(req.headers.range.replace(/\D/g, ''));
  const end = Math.min(start + chunkSize, size - 1);

  const contentLength = end - start + 1;

  res.setHeader('Content-Range', `bytes ${start}-${end}/${size}`);
  res.setHeader('Accept-Ranges', `bytes`);
  res.setHeader('Content-Length', contentLength);
  res.setHeader('Content-Type', `video/mp4`);

  res.status(206);

  const videoStream = createReadStream(fileAbsolutePath, { start, end });

  videoStream.pipe(res);