dnssd/bin/bin.build.js

Bonjour/Avahi-like service discovery in pure JavaScript

#!/usr/bin/env node
'use strict';

var dnssd = require('../index.js');

//
//
main(process.argv);
//
//


function showHelp(reason) {
  if (reason) console.log('\n' + reason);

  console.log('\nUsage: dnssd-js <command>\n');
  console.log('dnssd-js browse [type] [domain]');
  console.log('dnssd-js advertise <type> <port> [name] [txt]');
  console.log('dnssd-js query <record name> <record type>');
  console.log('dnssd-js address <hostname> [v4/v6]');

  process.exit();
}

function exit(err) {
  if (err) console.log('\n' + err + '\n');
  process.exit();
}

function padStart(value, len) {
  var filler = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : ' ';

  var str = String(value);
  var fill = String(filler);
  var needed = len - str.length;

  return needed > 0 ? fill.repeat(needed) + str : str;
}

function padEnd(value, len) {
  var filler = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : ' ';

  var str = String(value);
  var fill = String(filler);
  var needed = len - str.length;

  return needed > 0 ? str + fill.repeat(needed) : str;
}

function timestamp() {
  var now = new Date();

  var time = [padStart(now.getHours(), 2, 0), padStart(now.getMinutes(), 2, 0), padStart(now.getSeconds(), 2, 0), padStart(now.getMilliseconds(), 3, 0)];

  return '[' + time.join(':') + ']';
}

function print(time, status, type, instance) {
  console.log('%s  %s  %s  %s', padEnd(time, 14), padEnd(status, 4), padEnd(type, 20), instance);
}

function browse(serviceType, domain) {
  var browser = new dnssd.Browser(serviceType, { domain: domain });

  // format to:
  // [23:18:53:805]  Up    _http._tcp   Test @ box.local. (169.254.22.58:4576)
  browser.on('serviceUp', function (service) {
    print(timestamp(), 'Up', '_' + service.type.name + '._' + service.type.protocol, service.name + ' @ ' + service.host + ' (' + service.addresses[0] + ':' + service.port + ')');
  });

  browser.on('serviceDown', function (service) {
    print(timestamp(), 'Down', '_' + service.type.name + '._' + service.type.protocol, service.name + ' @ ' + service.host + ' (' + service.addresses[0] + ':' + service.port + ')');
  });

  browser.on('error', exit);
  browser.start();
}

function browseAll(domain) {
  console.log('Browsing for all available services:\n');
  print('Time', 'U/D', 'Service Type', 'Instance');
  print('----', '---', '------------', '--------');

  var browser = new dnssd.Browser(dnssd.all(), { domain: domain });
  var active = {};

  browser.on('serviceUp', function (type) {
    var serviceType = '_' + type.name + '._' + type.protocol;

    // only start one browser for each new service type
    if (!active[serviceType]) {
      active[serviceType] = true;
      browse(serviceType, domain);
    }
  });

  browser.on('error', exit);
  browser.start();
}

function browseType(type, domain) {
  if (!type || type === 'all') return browseAll(domain);

  var serviceType = void 0;

  // wrap in case type validation fails
  try {
    serviceType = new dnssd.ServiceType(type);
  } catch (err) {
    exit('Bad service type: ' + err.message);
  }

  console.log('Browsing for "' + serviceType + '":\n');
  print('Time', 'U/D', 'Service Type', 'Instance');
  print('----', '---', '------------', '--------');

  browse(serviceType, domain);
}

function advertise(type, portString, name, obj) {
  var port = parseInt(portString, 10);
  var txt = void 0,
      advertisement = void 0;

  if (!port) exit('Missing port number');
  if (!Number.isInteger(port)) exit('Bad port number');

  // parse txt string
  if (obj) {
    try {
      txt = JSON.parse(obj);
    } catch (err) {
      exit('Problem parsing txt object: ' + txt.message);
    }
  }

  // wrap in case advert args fail validation check
  try {
    advertisement = new dnssd.Advertisement(type, port, { name: name, txt: txt });
  } catch (err) {
    exit('Problem creating advertisement: ' + err.messsage);
  }

  console.log('Creating advertisement for "' + type + '"...');

  advertisement.on('active', function () {
    console.log('%s Advertisement now active', timestamp());
  });

  advertisement.on('instanceRenamed', function (instance) {
    console.log('%s Advertisement instance renamed "%s" due to a conflict.', timestamp(), instance);
  });

  advertisement.on('hostRenamed', function (host) {
    console.log('%s Advertisement hostname renamed "%s" due to a conflict.', timestamp(), host);
  });

  advertisement.on('stopped', function () {
    console.log('%s Advertisement stopped.', timestamp());
    exit();
  });

  advertisement.on('error', exit);
  advertisement.start();
}

function query(name, type) {
  if (!name) exit('Missing record name');
  if (!type) exit('Missing record type');

  // rrtype could be string (like TXT) or and int (like 16)
  var rrtype = Number.isInteger(parseInt(type, 10)) ? parseInt(type, 10) : type;
  var getRecord = void 0;

  // wrap to check for validation errors
  try {
    getRecord = dnssd.resolve(name, rrtype);
  } catch (err) {
    exit(err);
  }

  getRecord.then(function (result) {
    console.log('Found record: ' + result.answer);
  }).catch(function (err) {
    exit('Record not found. \nReason: ' + err.message);
  });
}

function address(hostname) {
  var IPv = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 'v4/v6';

  if (!hostname) exit('Missing hostname');

  var getIPv4 = void 0,
      getIPv6 = void 0;

  // wrap to check for validation errors
  try {
    if (!!~IPv.indexOf('v4')) getIPv4 = dnssd.resolveA(hostname);
    if (!!~IPv.indexOf('v6')) getIPv6 = dnssd.resolveAAAA(hostname);
  } catch (err) {
    exit(err);
  }

  if (!getIPv4 && !getIPv6) exit('Invalid address type given: ' + IPv);

  Promise.all([getIPv4, getIPv6]).then(function (results) {
    var IPv4 = results[0];
    var IPv6 = results[1];

    if (IPv4) console.log('Found IPv4 address: ' + IPv4);
    if (IPv6) console.log('Found IPv6 address: ' + IPv6);
  }).catch(function (err) {
    exit('Address not found. \nReason: ' + err.message);
  });
}

function main(args) {
  var commands = {
    browse: browseType,
    register: advertise,
    advertise: advertise,
    query: query,
    address: address
  };

  var command = args[2];

  if (!command || command === '-h' || command === '--help') showHelp();
  if (!(command in commands)) showHelp('Unknown command given');

  commands[command].apply(null, args.slice(3));

  process.on('SIGINT', exit);
  process.on('SIGTERM', exit);
  process.on('SIGQUIT', exit);
}