CoffeeScript function to create a long-polling server

long-polling.coffee

http = require 'http'

createLongPollingServer = (interval, {getData, returnData}) ->
  http.createServer (request, response) ->
    poll = ->
      data = getData request

      return setTimeout poll, interval if not data

      response.writeHead 200, 'Content-Type': 'text/plain'
      returnData response, data

    setTimeout poll, interval

server = createLongPollingServer 500 
  getData: (request) ->
    # a request of some resource would go here...
    'yippee!' if Math.random() > .5
  returnData: (response, data) ->
    response.end "#{ data }\n"

server.listen 8012, '127.0.0.1'
console.log 'Server running...'