server.js

var  request = require('request'),
express = require("express"),
config = require('./config'),
app = express(),
pingServer,
sendPing;

  app.configure(function() {
    app.use(express.bodyParser());
  });

  sendPing = function(url) {
    request.get(url, function() {
      console.log('RESPONSE FROM: ' + url);
      pingServer(url);
    });
  };

  pingServer = function(url) {
    var urlToPing = url;
    setTimeout(function(){
    console.log('PINGING ' + urlToPing + ' ' + new Date().toString());
      sendPing(urlToPing);
    }, config.pingFrequency);
  };

  for(var i=0; i < config.urlsToPing.length; i++) {
    var url = config.urlsToPing[i];
    pingServer(url);
  }

  pingServer(config.pingServerUrl);

var port = process.env.PORT || 3000;
var server = app.listen(port);
console.log("*****Server running on port " + port);