gistfile1.js

var http = require('http');
var fs   = require('fs');
var url  = require('url');

var settingsPath='settings2.json';

var Server = function(path){
	this.readSettings(path);
}

Server.prototype.readSettings=function(path){
	fs.readFile(path, 'utf8', function(err,data){
		if(err) throw err;
		Server.prototype.parseSettings(data);
	})
}

Server.prototype.parseSettings=function(data){
	this.options=JSON.parse(data);
	if(!this.options.downloadPath) throw new Error('downloadPath is not set in settings file');
	if(this.options.downloadPath.substring(this.options.downloadPath.length-1,1)!='/') this.options.downloadPath+'/';
	Server.prototype.findFiles();
}

Server.prototype.findFiles=function(){
        var server_ref = this; // saves a reference to this
	fs.readdir(this.options.downloadPath,function(err,files){
		if(err) throw err;
		server_ref.files={};
		for(var i in files){
			Server.prototype.addFile(files[i]);
		}
		console.log(JSON.stringify(server_ref.files));
	})
}
Server.prototype.addFile= function(filename){
	this.files[filename]={filename: filename, status: 'pre-stat'};
	fs.stat(this.downloadPath+filename, (function(err, stats){
		if(err) throw err;
		this.files[filename].size=stats.size;
		this.files[filename].status='ready';
	}).bind(this)); // using .bind you'll be instructing the function to execute with the given `this`
}
var s=new Server(settingsPath);