web server in node.js

webserver.js

var http = require("http");
var express = require("express")
var fs = require("fs")
var port = "8081";
var serverURL = "127.0.0.1";
var path = require("path")
console.log('Server running at ' + serverURL + ":" + port);

http.createServer(function (request, response) {


	var filename = request.url || "Energy.html";
	var now = new Date();
	var ext = path.extname(filename);
	var localpath = __dirname;

	var validExtensions = {
		".html" : "text/html",			
		".js": "application/javascript", 
		".css": "text/css",
		".txt": "text/plain",
		".jpg": "image/jpeg",
		".gif": "image/gif",
		".png": "image/png"
	};

	var isValidExt = validExtensions[ext];

	if (isValidExt) {
		localpath += filename;
		fs.exists(localpath, function(exists){
			if(exists){
				console.log("Serving File:" + filename)
				getFile(localpath, response, ext);				
				}
			else {
				console.log("File not Found:"+ filename)
				res.writeHead(404);
				res.end();
				}		
});
}
		else {
			console.log("Invalid extension:" +ext)
			}
}).listen(port, serverURL);

function getFile(localpath, response, mimeType) {
	fs.readFile(localpath, function(error, contents){
		if(!error) {
				response.setHeader("Content-Length", contents.length);
				response.setHeader("Content-Length",mimeType);
				response.statusCode = 200;
				response.end(contents);
				} else {
						response.writeHead(500);
						response.end();
					}
});
}