Rewind Server

rewind-server.js

'use strict';

const express      = require('express');
const fs           = require('fs');
const http         = require('http');
const https        = require('https');
const RewindBuffer = require('./lib/rewind-buffer');

let rewindBuffer = new RewindBuffer({maxFrames: 300});
let app          = express();
let httpsServer  = https.createServer({
  key: fs.readFileSync('./key.pem', 'utf8'),
  cert: fs.readFileSync('./cert.pem', 'utf8'),
  passphrase: "password"
}, app);


app.get('/stream', function (req, res) {
  res.writeHead(200, {'Content-Type': 'audio/mpeg'});
  let offset      = req.query.offset ? parseInt(req.query.offset) : 0;
  let isConnected = true;
  rewindBuffer.read(offset, (samples) => {
    res.write(Buffer.from(samples), 'binary');
    return isConnected;
  });
  let terminateRead = () => {
    console.log('client disconnected');
    isConnected = false;
  }
  req.on("close", terminateRead);
  req.on("end",   terminateRead);
});


httpsServer.listen(3003);

const options = {
  hostname: 'live.scpr.org',
  protocol: 'http:',
  path: '/kpcclive?ua=SCPRWEB&preskip=true'
};

http.get(options, (res) => {

  let secondBuffer    = []; // to buffer up 1 second of audio
  let frameCount      = 0;
  let syncWord        = '255,251';
  let nickelbackTimeout = null;

  function bufferAudio (d, x){
    let i   = 0;
    let len = d.length;
    while(i<len){
      let lastThreeBytes = secondBuffer.slice(secondBuffer.length - 2, secondBuffer.length);
      if(lastThreeBytes.toString() === syncWord){
        frameCount++;
      }
      if(frameCount >= 38){
        if(x){
          debugger
        }
        rewindBuffer.push(secondBuffer);
        secondBuffer = [];
        frameCount   = 0;
      }
      secondBuffer.push(d[i]);
      i++;
    }
  }

  function playNickelback(){
    let d = fs.readFileSync('./resources/nickelbackx.mp3');
    console.log('something went wrong');
    bufferAudio(d, true);
  }

  res.on('data', (d) => {
    clearTimeout(nickelbackTimeout);
    bufferAudio(d);
    nickelbackTimeout = setTimeout(playNickelback, 5000);
  });

});