harmonyhubjs-discover/lib/explorer.js

Discover available Logitech Harmony Hubs in the current network.

var debug = require('debug')('harmonyhubjs:discover:explorer')
var util = require('util')
var EventEmitter = require('events').EventEmitter
var Ping = require('./ping')
var ResponseCollector = require('./responseCollector')

function deserializeResponse (response) {
  var pairs = {}

  response.split(';')
    .forEach(function (rawPair) {
      var splitted = rawPair.split(':')
      pairs[splitted[0]] = splitted[1]
    })

  return pairs
}

function arrayOfKnownHubs (knownHubs) {
  return Object.keys(knownHubs).map(function (hubUuid) {
    return knownHubs[hubUuid]
  })
}

function handleResponse (data) {
  var hub = deserializeResponse(data)

  if (this.knownHubs[hub.uuid] === undefined) {
    debug('discovered new hub ' + hub.friendlyName)
    this.knownHubs[hub.uuid] = hub
    this.emit('online', hub)
    this.emit('update', arrayOfKnownHubs(this.knownHubs))
  } else {
    this.knownHubs[hub.uuid].lastSeen = new Date()
  }
}

function executeCleanUp () {
  debug('executeCleanUp()')

  var self = this
  var now = new Date()

  Object.keys(self.knownHubs).forEach(function (hubUuid) {
    var hub = self.knownHubs[hubUuid]
    var diff = now - hub.lastSeen

    if (diff > 5000) {
      debug('hub at ' + hub.ip + ' seen last ' + diff + 'ms ago. clean up and tell subscribers that we lost that one.')
      delete self.knownHubs[hubUuid]
      self.emit('offline', hub)
      self.emit('update', arrayOfKnownHubs(self.knownHubs))
    }
  })
}

function Explorer (port, pingOptions) {
  debug('Explorer(' + port + ')')
  EventEmitter.call(this)

  this.knownHubs = {}
  this.port = port
  this.ping = new Ping(this.port, pingOptions)
}
util.inherits(Explorer, EventEmitter)

Explorer.prototype.start = function start () {
  debug('start()')

  this.responseCollector = new ResponseCollector(this.port)
  this.responseCollector.on('response', handleResponse.bind(this))
  this.cleanUpIntervalToken = setInterval(executeCleanUp.bind(this), 5000)

  this.responseCollector.start()
  this.ping.start()
}

Explorer.prototype.stop = function stop () {
  debug('stop()')

  this.ping.stop()
  this.responseCollector.stop()
  clearInterval(this.cleanUpIntervalToken)
}

module.exports = Explorer