EGTS_SR_POS_DATA parser (EGTS_TELEDATA_SERVICE)

index.js

const net = require('net');

var getBits = (octet) => {
  var bits = [];
  for (var i = 7; i >= 0; i--) {
    var bit = octet & (1 << i) ? 1 : 0;
    bits.push(bit);
  }
  return bits;
};

var getUInt = (valArr, base) => {
  if(!base) {
    base = 256;
  }
  return valArr.reduce((mem, cur, index) => {
    return mem + (cur * Math.pow(base, index));
  }, 0);
};

var secsFrom1970to2010 = 1262304000;

const server = net.createServer((socket) => { //'connection' listener
  console.log('client connected');
  socket.on('end', () => {
    console.log('client disconnected');
  });
  socket.on('data', (data) => {
    var byteArray = new Uint8Array(data);

    console.log('------------------------------------------------------------------------------------');
    console.log('Date:', new Date());
    console.log('Packed data:');
    console.log(' ', new Buffer(data).toString('hex'));
    console.log(' ', byteArray.toString());
    console.log('\n');
    console.log('EGTS Transport Layer:');
    console.log('---------------------');
    console.log('  Protocol Version    -', byteArray[0].toString());
    console.log('  Security Key ID     -', byteArray[1].toString());
    var flagsBits = getBits('0x' + new Buffer([byteArray[2]]).toString('hex'));
    console.log('  Flags               -', flagsBits.join(''));
    console.log(`
     Prefix         - ${flagsBits.slice(0, 2).join('')}
     Route          -   ${flagsBits[2]}
     Encryption Alg -    ${flagsBits.slice(3, 5).join('')}
     Compression    -      ${flagsBits[5]}
     Priority       -       ${flagsBits.slice(6, 8).join('')} (the highest)`);
    console.log('  Header Length       -', byteArray[3].toString());
    console.log('  Header Encoding     -', byteArray[4].toString());
    console.log('  Frame Data Length   -', byteArray.slice(5, 7).reduce((mem, val) => mem + val, 0).toString());
    console.log('  Packet ID           -', getUInt(byteArray.slice(7, 9)));
    console.log('  No route info       -');
    console.log('  Header Check Sum    -', '0x' + byteArray[10].toString());
    console.log('');
    console.log('EGTS Service Layer:');
    console.log('---------------------');
    console.log('  Packet Type         -', byteArray[9].toString());
    console.log('');
    console.log('    Service Layer Record:');
    console.log('    ---------------------');
    console.log('    Record Length               -', byteArray.slice(11, 13).reduce((mem, val) => mem + val, 0).toString());
    console.log('    Record Number               -', byteArray.slice(13, 15).reduce((mem, val) => mem + val, 0).toString());
    var recordFlagsBits = getBits('0x' + new Buffer([byteArray[15]]).toString('hex'));
    console.log('    Record flags                -     ', recordFlagsBits.join(''));
    console.log(`
        Source Service On Device    - ${recordFlagsBits[0]}
        Recipient Service On Device -  ${recordFlagsBits[1]}
        Group Flag                  -   ${recordFlagsBits[2]}
        Record Processing Priority  -    ${recordFlagsBits.slice(3, 5).join('')}
        Time Field Exists           -      ${recordFlagsBits[5]}
        Event ID Field Exists       -       ${recordFlagsBits[6]}
        Object ID Field Exists      -        ${recordFlagsBits[7]}`);
    console.log('    Object Identifier           -', getUInt(byteArray.slice(16, 20)));
    console.log('    Source Service Type         -', byteArray[20].toString());
    console.log('    Recipient Service Type      -', byteArray[21].toString());
    console.log('       Subrecord Data:');
    console.log('       ------------------');
    console.log('       Subrecord Type      -', byteArray[22].toString());
    console.log('       Subrecord Length    -', getUInt(byteArray.slice(23, 25)));
    console.log('       Navigation Time     -', new Date((getUInt(byteArray.slice(25, 29)) + secsFrom1970to2010) * 1000));
    console.log('       Position Latitude   -', (getUInt(byteArray.slice(29, 33)) * 90) / 4294967295);
    console.log('       Position Longitude  -', (getUInt(byteArray.slice(33, 37)) * 180) / 4294967295);
    console.log('');
    var subRecordFlagsHexBuffer = new Buffer([byteArray[37]]).toString('hex'),
        subRecordFlagsBits = getBits('0x' + subRecordFlagsHexBuffer);

    console.log('       Record flags        -     ', subRecordFlagsBits.join(''), '(', '0x' + subRecordFlagsHexBuffer, ')');
    console.log(`
          Altitude exist         - ${subRecordFlagsBits[0]}
          Longitude hemisphere   -  ${subRecordFlagsBits[1] == 0 ? 'east' : 'west'}
          Latitude hemisphere    -   ${subRecordFlagsBits[2] == 0 ? 'north' : 'south'}
          Is moving?             -    ${subRecordFlagsBits[3]}
          Black box              -     ${subRecordFlagsBits[4]}
          Coordinates system     -      ${subRecordFlagsBits[5] == 0 ? 'WGS-84' : 'ПЗ-90.02'}
          FIX                    -       ${subRecordFlagsBits[6] == 0 ? '2D fix' : '3D fix'}
          Is valid?              -        ${subRecordFlagsBits[7]}`);
    console.log('');
    //console.log('       Speed                -     ', subRecordFlagsBits.join(''));
    //console.log('       direction                -     ', subRecordFlagsBits.join(''));
    console.log('       Odometer            -     ', getUInt(byteArray.slice(41, 44)));
    console.log('       Source              -     ', byteArray[45]);
    console.log('       Altitude            -     ', getUInt(byteArray.slice(46, 48)));



    console.log('=================================');
  });
});
server.listen(8124, () => { //'listening' listener
  console.log('server bound');
});