using node to display realtime heatmap of user's clicks

server.js

var sys = require('sys'),
		fs = require('fs'),
		Url = require('url'),
        http = require('http'),
		querystring = require('querystring');
		

//create a Heatmap Obj that inherits
//from EventEmitter
var events = require('events');
function Heatmap() {
    events.EventEmitter.call(this);
};
Heatmap.super_ = events.EventEmitter;
Heatmap.prototype = Object.create(events.EventEmitter.prototype, {
    constructor: {
        value: Heatmap,
        enumerable: false
    }
});

//save dataPoint and emit event 'added'
//that is listened to by displayNewDataPoints
Heatmap.prototype.add = function(xyPoints) {
    var self = this;
    self.xyPoints = xyPoints;
    fs.open("./clickcount.txt", "a", 0666, function(er, fd){
		var timeStamp = Math.round(new Date().getTime() / 1000);
		fs.write(fd, xyPoints.x+','+xyPoints.y+";\n", null);
		console.log('displaying new points. x: '+xyPoints.x + ' y:'+xyPoints.y);
		self.emit('added', self.xyPoints);
	});
};

//create an instance of Heatmap
//we'll use this in the requests
var MyHeatmap = new Heatmap();

//get datapoints from querystring
//save datapoinst to file
//and emit event
var addDataPoint = function(req, res){
	var formData = [];
	var urlObj = Url.parse(req.url, true);	
        
	if (urlObj.query["x"] === undefined) { 
        res.end('0');
        return;
	}
	
	if (urlObj.query["y"] === undefined) { 
        res.end('0');
        return;
	}
	
	formData.x = urlObj.query["x"];
    formData.y = urlObj.query["y"];
    
	
	MyHeatmap.add(formData);
	
	res.end('1');
};

//responds to request when new click is sent
//to /addDataPoint, otherwise hangs
var displayNewDataPoints = function(req, res) {
    MyHeatmap.on('added', function(dt) {
        //console.log('displaying new points. x: '+dt.x + ' y:'+dt.y);
        
        //print client side js so client heatmap 
        //display functions are called
        //and recall this url again
        var str = 'xx.addDataPoint('+dt.x+","+dt.y+');';
        str += 'ajad_send(nurl);';
        res.write(str,'utf8');
        res.end();
    });
};

//@todo display heatmap using last n dataPoints from file
var displayCurrentDataPoints = function(req, res) {
    fs.readFile("./clickcount.txt", function(err, data){
        res.write( data.toString() );
        res.end();
    });

};

//basic basic routing
var router = { "/" : displayCurrentDataPoints, 
                "/addDataPoint" : addDataPoint, 
                "/newDataPoints" : displayNewDataPoints  
            };

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/javascript'});
    var requestPath = Url.parse(req.url).pathname;
    console.log(requestPath);
    try {
        router[requestPath](req, res);
    } catch(e) {
        res.end('');
    }
    
    
}).listen(8000);