file_server.js

var http = require('http');
var parse = require('url').parse;
var join = require('path').join;
var fs = require('fs');
var root = __dirname;

var server = http.createServer(function(req, res){
    var url = parse(req.url);
    var path = join(root, url.pathname);
    fs.stat(path, function(err, stat){
        if (err) {
            if ('ENOENT' == err.code) {
                res.statusCode = 404;
                res.end('Not Found');
            } else {
                res.statusCode = 500;
                res.end('Internal Server Error');
            }
        } else {
            res.setHeader('Content-Length', stat.size);
            var stream = fs.createReadStream(path);
            stream.pipe(res);
            stream.on('error', function(err){
                res.statusCode = 500;
                res.end('Internal Server Error');
            });
        }
    });
});

server.listen(3000);