program.js

var args = process.argv.slice(2);
var http = require('http');
var map = require('through2-map');

var server = http.createServer(function(req, res) {
    req.pipe(map(function(chunk) {
        return chunk.toString().toUpperCase();
    })).pipe(res);
    //console.log(req.pipe);
});

server.listen(+args[0]);