Streaming audio in Node.js with Content-Range

Question

I\'m using a streaming server in Node.js to stream MP3 files. While the whole file streaming it is ok, I cannot use the Content-Range header to stream the file

Answer 1

I'm using expressjs framework and I've made it like this:

// Readable Streams Storage Class
class FileReadStreams {
  constructor() {
    this._streams = {};
  }

  make(file, options = null) {
    return options ?
      fs.createReadStream(file, options)
      : fs.createReadStream(file);
  }

  get(file) {
    return this._streams[file] || this.set(file);
  }

  set(file) {
    return this._streams[file] = this.make(file);
  }
}
const readStreams = new FileReadStreams();

// Getting file stats and caching it to avoid disk i/o
function getFileStat(file, callback) {
  let cacheKey = ['File', 'stat', file].join(':');

  cache.get(cacheKey, function(err, stat) {
    if(stat) {
      return callback(null, stat);
    }

    fs.stat(file, function(err, stat) {
      if(err) {
        return callback(err);
      }

      cache.set(cacheKey, stat);
      callback(null, stat);
    });
  });
}

// Streaming whole file
function streamFile(file, req, res) {
  getFileStat(file, function(err, stat) {
    if(err) {
      console.error(err);
      return res.status(404);
    }

    let bufferSize = 1024 * 1024;
    res.writeHead(200, {
      'Cache-Control': 'no-cache, no-store, must-revalidate',
      'Pragma': 'no-cache',
      'Expires': 0,
      'Content-Type': 'audio/mpeg',
      'Content-Length': stat.size
    });
    readStreams.make(file, {bufferSize}).pipe(res);
  });
}

// Streaming chunk
function streamFileChunked(file, req, res) {
  getFileStat(file, function(err, stat) {
    if(err) {
      console.error(err);
      return res.status(404);
    }

    let chunkSize = 1024 * 1024;
    if(stat.size > chunkSize * 2) {
      chunkSize = Math.ceil(stat.size * 0.25);
    }
    let range = (req.headers.range) ? req.headers.range.replace(/bytes=/, "").split("-") : [];

    range[0] = range[0] ? parseInt(range[0], 10) : 0;
    range[1] = range[1] ? parseInt(range[1], 10) : range[0] + chunkSize;
    if(range[1] > stat.size - 1) {
      range[1] = stat.size - 1;
    }
    range = {start: range[0], end: range[1]};

    let stream = readStreams.make(file, range);
    res.writeHead(206, {
      'Cache-Control': 'no-cache, no-store, must-revalidate',
      'Pragma': 'no-cache',
      'Expires': 0,
      'Content-Type': 'audio/mpeg',
      'Accept-Ranges': 'bytes',
      'Content-Range': 'bytes ' + range.start + '-' + range.end + '/' + stat.size,
      'Content-Length': range.end - range.start + 1,
    });
    stream.pipe(res);
  });
}

router.get('/:file/stream', (req, res) => {

  const file = path.join('path/to/mp3/', req.params.file+'.mp3');

  if(/firefox/i.test(req.headers['user-agent'])) {
    return streamFile(file, req, res);
  }
  streamFileChunked(file, req, res);
});

Full sources of site here

Try to fix to Your code:

this will enforce browser to act with resource as chunked.

var header = {
    'Content-Length': range[1],
    'Content-Type': type,
    'Access-Control-Allow-Origin': req.headers.origin || "*",
    'Access-Control-Allow-Methods': 'POST, GET, OPTIONS',
    'Access-Control-Allow-Headers': 'POST, GET, OPTIONS',
    'Cache-Control': 'no-cache, no-store, must-revalidate',
    'Pragma': 'no-cache',
    'Expires': 0
  };

  if(/firefox/i.test(req.headers['user-agent'])) {  
    res.writeHead(200, header);
  }
  else {
    header['Accept-Ranges'] = 'bytes';
    header['Content-Range'] = 'bytes ' + range[0] + '-' + range[1] + '/' + total;
    header['Content-Length'] = range[2];
    res.writeHead(206, header);
  }