OAuth - Cross-Site Authentication

Nowadays its normal for users to PUSH/PULL data TO/FROM 3rd party Web Applications to your Website.
eg: Facebook LIKE button

USE CASE
1.     A User (or You on behalf of the User) wants to login to their account
        on a 3rd party Web Application and pass data to your Web Application?
eg:  Tweet from your website using their twittername
       Check their Gmail from your website

QUESTION:
Can a user submit their Login Credentials via your WebApp and expect you to securely handle their Sensitive Data?
How does your Web App Authorise & Store their Login Credentials?
How does your website make Requests based on Their Login Credentials?

ANSWER:
OAuth v1 or v2

WIth an OAuth Client connecting to an OAuth Server, we can solve the above USE CASE.

Study the above Diagram for an Overview of OAuth v1
When you're ready to connect to 3rd party Web Apps...read their DOcumentation of their implementation of OAuth since methods and names may change.

Client Side implementation of OAuth
With Browser side code you have no way of PREVENTING people from seeing your Secret 'oauth_consumer_key' and 'oauth_toke_secret'.
StackOverFlow.com Article  StackOverFlow Article 2
Read the following Very Interesting Article for some ideas to solve Client Side OAuth implementation Security Problems. http://derek.io/blog/2010/how-to-secure-oauth-in-javascript/

Note:
You should also understand
SAME-ORIGIN POLICY
SAME-OROGIN POLICY 2
JsonP

Memoization

Once an expensive function runs, it can rewrite itself with an optimized version.

Memoization is a technique similar to caching that takes advantage of

the fact that functions are just data.

var getElement = function() {



    console.log("creating element");

    var element = document.createElement("div");



    // ... Do a bunch of expensive operations



    // Now OVERWRITE this function with a SIMPLER VERSION

    getElement = function() {

        return element;

    };



    return element;

};

The first time getElement runs, it creates the element and runs a bunch
of code with it. Then it rewrites the getElement function to solely return the created element. This makes subsequent calls to getElement much quicker.

Source:  "The JavaScript PocketGuide" - Lenny Burdette 2010

Beautiful HTML - Example

Great Article

Source: http://css-tricks.com/examples/CleanCode/Beautiful-HTML.png

Catalog of Patterns of Enterprise Application Architecture - Martin Fowler

  One of my Essential Resources on Understanding Software Design Patterns

Domain Logic Patterns: Transaction Script (110), Domain Model (116), Table Module (125), Service Layer (133).

Data Source Architectural Patterns: Table Data Gateway (144), Row Data Gateway (152), Active Record (160), Data Mapper (165).

Object-Relational Behavioral Patterns: Unit of Work (184), Identity Map (195), Lazy Load (200)

Object-Relational Structural Patterns: Identity Field (216), Foreign Key Mapping (236), Association Table Mapping (248), Dependent Mapping (262), Embedded Value (268), Serialized LOB (272), Single Table Inheritance (278), Class Table Inheritance (285), Concrete Table Inheritance (293), Inheritance Mappers (302).

Object-Relational Metadata Mapping Patterns: Metadata Mapping (306), Query Object (316), Repository (322).

Web Presentation Patterns: Model View Controller (330), Page Controller (333), Front Controller (344), Template View (350), Transform View (361), Two-Step View (365), Application Controller (379).

Distribution Patterns: Remote Facade (388), Data Transfer Object (401)

Offline Concurrency Patterns: Optimistic Offline Lock (416), Pessimistic Offline Lock (426), Coarse Grained Lock (438), Implicit Lock (449).

Session State Patterns: Client Session State (456), Server Session State (458), Database Session State (462).

Base Patterns: Gateway (466), Mapper (473), Layer Supertype (475), Separated Interface (476), Registry (480), Value Object (486), Money (488), Special Case (496), Plugin (499), Service Stub (504), Record Set (508)

PHP Architecture - 3 tier & MVC

Great Articles on Architecture here 

http://www.tonymarston.net/php-mysql/sample-application.html