XHRPollingSocket.js

var events = require('events')
  , util   = require('util')
  , uuid   = require('uuid')

module.exports = XHRPollingSocket

// ws should be open and valid
function XHRPollingSocket(ws) {
  events.EventEmitter.call(this)
  var self       = this
  this.buffer    = []
  this.is_closed = false
  this.id        = uuid.v1()
  this.timeout   = null
  this.ws        = ws
  this.ws.once('close', function() {
    console.log('websocket:close')
    self.close()
  })
  this.ws.on('message', function(data) {
    self.send_client(data)
  })
}
util.inherits(XHRPollingSocket, events.EventEmitter)

XHRPollingSocket.prototype.close = function() {
  if (!this.is_closed) {
    this.buffer.push({event: 'close'})
    if (this.client) {
      this.set_client(this.client)
    }
    this.ws.removeAllListeners()
    this.ws.close()
    this.emit('close')
  }
  this.is_closed = true
}

XHRPollingSocket.prototype.send_ws = function(data) {
  this.ws.send(data) 
}

XHRPollingSocket.prototype.send_client = function(data) {
  this.buffer.push({event: 'message', data: data})
  if (this.client) {
    this.set_client(this.client)
  }
}

XHRPollingSocket.prototype.set_client = function(client) {
  if (this.timeout) {
    clearTimeout(this.timeout)
  }
  var self = this
  if (this.buffer.length) {
    client.json({events: this.buffer})
    this.buffer = []
    this.client = null
    // we just had contact with this fella, so we're expecting a quick response
    this.timeout = setTimeout(function() {
      console.log('didn\'nt hear back, closing socket...')
      self.close()
    }, 5000)
  } else {
    this.client = client
    // we've got a pending connection... but nothing to say, so let's hold it for a time and then send a heartbeat
    this.timeout = setTimeout(function() {
      console.log('sending heartbeat')
      self.buffer.push({event: 'heartbeat'})
      self.set_client(self.client)
    }, 15000)
  }
}