dashcam.js

var CHANNEL, CHUNK_SIZE, CLIENT_NAME, H_RES, PHOTO_INTERVAL, V_RES, child, fs, imageCallback, pn, pnCfg;

fs      = require('fs'); // included with nodejs
child   = require('child_process'); // included with nodejs

CLIENT_NAME    = 'dashcam-001';
CHANNEL        = 'dashcam-demo';
CHUNK_SIZE     = 1024 * 28;
PHOTO_INTERVAL = 10000;
H_RES          = (400).toString();
V_RES          = (300).toString();

pnCfg = {
  publish_key:   'YOUR_PUB_KEY',
  subscribe_key: 'YOUR_SUB_KEY',
  uuid: CLIENT_NAME,
  ssl: true
};

pn = (require('pubnub')).init(pnCfg);

process.on('SIGINT', function() {
  console.log('Dashcam Stopped');
  return process.exit();
});

imageCallback = function() {
  var args, fname, spawn, ts;
  ts = new Date().toISOString().replace(/[:\-]/g, "").replace(/\.\d{3}/g, "");
  fname = "photo/image_" + ts + ".jpg";

  args = ['-w', H_RES, '-h', V_RES, '-o', fname, '-t', '1', '-vf'];
  spawn = child.spawn('raspistill', args);

  return spawn.on('exit', function(code) {
    var buffer, content, i, imagePt, imgLen, msg, total;

    buffer = fs.readFileSync(fname);
    content = "data:image/jpeg;base64," + buffer.toString('base64').replace(/\n/g, "");
    total = Math.ceil(content.length / CHUNK_SIZE);

    console.log(CLIENT_NAME + " publish: " + fname);
    i = 0;

    while (i < total) {
      imgLen = i < total - 1 ? CHUNK_SIZE : content.length % CHUNK_SIZE;
      imagePt = content.substring(i * CHUNK_SIZE, (i * CHUNK_SIZE) + imgLen);
      msg = {
        uuid: CLIENT_NAME,
        ts: ts,
        i: i,
        n: total,
        imgPart: imagePt
      };
      i += 1;
      pn.publish({
        channel: CHANNEL,
        message: msg
      });
    }
  });
};

setInterval(imageCallback, PHOTO_INTERVAL);
console.log('Dashcam Starting');