Pixel Code in Node js whenever you used insert in href of img tag

node-1x1-pixel.js

var fs = require('fs'),
    http = require('http'),
    url = require('url'),
    img = fs.readFileSync(__dirname + '/stat.png'),
    stats = {};

var collectStats = function(type) {
    console.log('collectStats type=' + type);
    if(!stats[type]) stats[type] = 0;
    stats[type]++;
}

http.createServer(function(req, res){
    var request = url.parse(req.url, true);
    var action = request.pathname;
    if (action == '/stat.png') {
        collectStats(request.query.type);
        res.writeHead(200, {'Content-Type': 'image/gif', 'Cache-Control': 'no-cache' });
        res.end(img, 'binary');
    } else {
        res.writeHead(200, {'Content-Type': 'text/html' });
        res.end('Stats server:<pre>' + JSON.stringify(stats) + '</pre>\n');
    }
}).listen(8000, '127.0.0.1');
console.log('Server is running at http://127.0.0.1:8000');


// Uses Example
// * http://127.0.0.1:8000/ - shows the collected statistics
// * http://127.0.0.1:8000/stat.png?type=something - collecting statistics.