Scan Uri Beacons with Web Bluetooth

uribeacon.js

navigator.mozBluetooth.defaultAdapter.startLeScan([]).then(handle => {
  console.log('Start scanning', handle);
  handle.ondevicefound = e=> {
    var uri = parseUriBeacon(e.scanRecord);
    if (uri) {
      return console.log('Found UriBeacon', uri);
    }
  }

  setTimeout(() => {
    console.log('Stop scanning');
    navigator.mozBluetooth.defaultAdapter.stopLeScan(handle)
  }, 5000);

}, err => console.error(err))

function parseUriBeacon(scanRecord) {
  var data = new Uint8Array(scanRecord);

  for (var b = 0; b < 8; b++) {
    if (data[b] === 0x03 && data[b + 1] === 0x03 &&
        data[b + 2] === 0xd8 && data[b + 3] === 0xfe) {
      break;
    }
  }

  if (b === 8) {
    return false;
  }

  var schemes = [
    'http://www.',
    'https://www.',
    'http://',
    'https://',
    'urn:uuid:'
  ];

  var expansions = [
    '.com/',
    '.org/',
    '.edu/',
    '.net/',
    '.info/',
    '.biz/',
    '.gov/',
    '.com',
    '.org',
    '.edu',
    '.net',
    '.info',
    '.biz',
    '.gov',
  ];

  b += 4;
  var adLength = data[b++];
  var adType = data[b++];
  b += 2; // skip Service UUID
  var flags = data[b++];
  var txPower = data[b++];
  var scheme = data[b++];

  var text = schemes[scheme];
  // it has been 0x06 bytes since we read adLength, so take that into account
  for (var i = b, c = data[i]; i < b + adLength - 0x06; c = data[++i]) {
    if (c < expansions.length) {
      text += expansions[c];
    }
    else {
      text += String.fromCharCode(c);
    }
  }

  return text;
}