NodeJS Simple Static Server

staticserver.js

var http = require("http"),
    url = require("url"),
    path = require("path"),
    fs = require("fs")
    port = process.argv[2] || 8888;

var guessContentType = (function () {
    var CONTENT_TYPE_OCTET_STREAM = "application/octet-stream";
    
    var DEFAULT_CONTENT_TYPES = {
        "html": "text/html",
        "js": "text/javascript",
        "png": "image/png"
    };
    
    function guessContentType(filename) {
        var dot = filename.lastIndexOf(".");
        if (dot <= 0) {
            return CONTENT_TYPE_OCTET_STREAM;
        }
    
        var ext = filename.substring(dot + 1).toLowerCase();
        var mimeType = DEFAULT_CONTENT_TYPES[ext];
    
        return mimeType || CONTENT_TYPE_OCTET_STREAM;
    }

    return guessContentType;
})();


http.createServer(function(request, response) {
    var uri = url.parse(request.url).pathname, 
        filename = path.join(process.cwd(), uri);

    fs.exists(filename, function(exists) {
        if (!exists) {
            response.writeHead(404, {
                "Content-Type": "text/plain"
            });
            response.write("404 Not Found\n");
            response.end();
            return;
        }

        if (fs.statSync(filename).isDirectory()) {
            filename += '/index.html';
        }

        fs.readFile(filename, "binary", function(err, file) {
            if(err) {
                response.writeHead(500, {"Content-Type": "text/plain"});
                response.write(err + "\n");
                response.end();
                return;
            }

            response.writeHead(200, {
                "Content-Type": guessContentType(filename)
            });
            response.write(file, "binary");
            response.end();
        });
    });
}).listen(parseInt(port, 10));

console.log("Static file server running at\n => http://localhost:" + port + "/\nCTRL + C to shutdown.\n" +
            "Open http://localhost:8888/server.js to see the sample");