TimBeyer

//\/////
//\  overLIB 4.22 - You may not remove or change this notice.
//\  Copyright Erik Bosrup 1998-2004. All rights reserved.
//\
//\  Contributors are listed on the homepage.
//\  This file might be old, always check for the latest version at:
//\  http://www.bosrup.com/web/overlib/
//\
//\  Please read the license agreement (available through the link above)
//\  before using overLIB. Direct any licensing questions to erik@bosrup.com.

TimBeyer

'use strict';

var assert = require('assert'),
  director = require('director'),
  EventEmitter = require('events').EventEmitter,
  ns,// = require('continuation-local-storage').createNamespace('testing'),
  express = require('express'),
  app = express(),
  domain = require('domain');

TimBeyer

var uuid = require('node-uuid');
var _ = require('lodash');

var privates = {};

function MyClass () {
    this.id = uuid.v4();
    privates[this.id].foobar = 'somethingprivate';
};

TimBeyer

var items = [{'price': 123, 'tax': 0.1}, {'price': 234, 'tax': 0.3}];

var taxCalculator = function (items) {
        
    var taxedMapper = function (item) {
        return item.price + item.price * item.tax;
    };
    
    var nonTaxedMapper = function (item) {
        return item.price;

TimBeyer

Working using domains

In this example we'd like to have a factory that works per request and allows to keep track of created Models We create a factory per request and create a domain to which we attach the factory That way the singleton is automatically shared with all parts of the application under process.domain.*

TimBeyer

Working but complicated

In this example we'd like to have a factory that works per request and allows to keep track of created Models We create a factory per request and pass it around to the parts of the code that need access This can quickly lead to hard to understand, messy code

TimBeyer

// In this example we'd like to have a factory that works per request and allows to keep track of created Models
// The singleton will however apply to all requests and thus keep growing
// For that reason we supply it with a reset function.
// This works fine until between receiving a request and sending a response there is no asynchronous code execution
// Once multiple requests come in in very short intervals, the asynchronous execution will lead to requests cross-polluting
// the singleton class

// factory.js
// 
// Should be per-request so we can keep track