stream-resume.js

const Stream = require('stream');
const https = require('https');
const http = require('http');
const URL = require('url');

/**
 * Resumable stream via a Stream PassThrough
 * @param {string|URL} url Input url
 * @param {stream.Transform} [output=stream.PassThrough] Output stream
 * @param {Object} [meta] Meta information to pass between stuff
 * @returns {stream.Transform}
 * @example
 * const Speaker = require('speaker');
 *
 * const speaker = new Speaker({
 *   channels: 2,
 *   bitDepth: 16,
 *   sampleRate: 44100,
 * });
 *
 * require('./')('http://www.music.helsinki.fi/tmt/opetus/uusmedia/esim/a2002011001-e02.wav').pipe(speaker);
 */
function streamIt(url, output = new Stream.PassThrough(), meta = { downloaded: 0, total: 0 }) {
  if (output._destroyed) return output;

  let input;

  output.destroy = function destroy() {
    this._destroyed = true;
    if (input) {
      input.unpipe();
      input.destroy();
    }
  };

  const options = typeof url === 'string' ? URL.parse(url) : url;
  options.headers = {};

  (url.startsWith('https') ? https : http).get(options, (res) => {
    output.resume();
    input = res;

    if (meta.downloaded === 0) meta.total = Number(input.headers['content-length']);

    input.on('data', (chunk) => {
      meta.downloaded += Buffer.byteLength(chunk);
    });

    input.on('end', () => {
      if (meta.downloaded < meta.total) {
        input.unpipe();
        options.headers.Range = `bytes=${meta.downloaded}`;
        streamIt(options, output, meta);
      } else {
        output.end();
      }
    });

    input.on('error', (err) => {
      if (!err) return;
      if (err.message === 'read ECONNRESET') {
        output.pause();
        return;
      }

      output.emit('error', err);
    });

    input.pipe(output, { end: false });
  });

  return output;
}

module.exports = streamIt;

url.startsWith('https') should be options.protocol === 'https:', If it starts again url is a parsed object
The range header should also be bytes=${meta.downloaded}- not bytes=${meta.downloaded}