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using node to display realtime heatmap of user's clicks
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);
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