Rich Internet Applications

Rich Internet Applications are the next wave in User Interfaces (Google Gmail, Google RSS Reader, Google Finance etc). AJAX (Asynchronous JavaScript and XML) is a key technology in this direction. RIA’s are designed to deliver 8A’s of software simplicity. 8A’s is Bill Gates old information at your finger tips or IBM SAA (System Application Architecture). According to Gartner (Article: RIA’s are the next evolution of the web by Mark, Ray, Gene) at least 60% of the application development in 2010 will include RIA technologies and 25% in that will primarily on RIA.

Applications Able to deliver Access to Anyone Authorized Anytime, Anyplace on Any Device.

Evolution of the Application User Interface

From the command line user interfaces in the 80’s to the Client Server based Graphical User interfaces in the early 90’s to the Web based applications in the late 90s and currently to the Rich Internet Applications which has the thin client framework with features of the Thick Clients (Client Server GUI).

Main Frame Text UI > Client Server Apps GUI > Web Apps (Web Pages) > RIA

AJAX technologies are not new. All the components in Ajax technologies existed from 1998 onwards. The term AJAX was born in 2005 and made it popular by Google applications like Google Suggest, Google Maps and GMail. Even Microsoft through its Atlas project is pushing the AJAX developments. The term AJAX was coined by Jesse James Garret of Adaptive Path. The Following diagram shows the comparison between a traditional Web Application with an AJAX based web application. In the traditional model all the request are based on a user action and every request require a new web page to be returned by the web server. In the new model initial request is based on the user action and then lot of asynchronous request(s) were made from the RIA (the client) to the server to give a traditional thick client user experience.

New Architecture Model – Four Layers of App Stack (FLAST)

This New Architecture model is similar to the IP Protocol Stack. Following diagram illustrates the details of each layer. Client Layer focuses on the Browser with AJAX Engines / Macromedia Flash Engines etc. This layer gives a Rich Interface to the end user similar to Client side heavy GUI applications. This layer transparently talks to the back end presentation layer build using JSP, ASP, PHP or Servlets. Asynchronous calls where made from the Client layer to the Presentation Layer. Presentation Layer talks to the Business Layer for handling the Business functions which in turn talks to the infrastructure layer to store and retrieve the data.

Features of AJAX

• GUI Widgets Rich Applications in the Web model without the support Java or Flash compared to the static or dynamic HTML pages.
  
• It uses existing technologies like JavaScript, XML. The backend can be written in PHP, Perl, Java, C# etc. This helps to avoid any new technology learning curve for the developers. So, the developers can use their existing skill set to develop highly interactive AJAX web based applications.
  
• AJAX applications run on any browser which supports JavaScript (and enabled). This makes a wide Browser support under all platforms at any time.
  
• These applications even run on low bandwidth environments.
• RIA is deployed without a separate installation process.

Key points to consider and aware of when you build an application using AJAX.

• AJAX apps are not traditional ‘Web Page’ based system where you can bookmark a page. It’s an application so what is more important is to think about the application states rather than pages.
• Keep in mind the behavior of ‘Back’ and ‘Forward’ buttons of the browsers. As this is not a ‘Page’ based system. AJAX applications refreshes internal areas with out reloading or changing the ‘Web Page’.
• Spiders (Search Engine Crawlers) will not be able to index your pages for searches.
• Users may disable JavaScript in their browsers.

AJAX Quick Start Development Kit

The packages identified in this section are for development purposes only. You need to take extra care to secure the PHP, MySQL and other packages with proper passwords and other security controls. XAMPP is a collection of popular open source tools. Developers at Apache Friends did a great job in bringing all these together and the installation and configuration is absolutely smooth. Download XAMPP (v1.5.2) from http://www.apachefriends.org/en/index.html available for both Linux and Windows. This will install the following packages.

o Apache 2.2
o PHP (5.1.2)
o MySQL (5.0.20)
o Perl
o FileZilla FTP Server
o Mercury Mail Server

There are lot of popular JavaScript libraries which gives table grids, pull down menus, drag and drop features, tree widgets etc. One of the most famous is ‘script.aculo.us’. Download the latest JavaScript library from http://script.aculo.us/ and the 'OpenLaszlo' open source development platfom for the Rich Internet Appliations.

Other JavaScript Library Collections
o http://www.mochikit.com/demos.html
o http://edevil.wordpress.com/2005/11/14/javascript-libraries-roundup/
o http://cross-browser.com/
o http://www.rawdata.net/developer/web_developer/ajax_javascript_librabries.php
o http://www.ajaxmatters.com/r/resources?id=17

Conclusion

Rich Internet Applications using AJAX technologies looks very promising. Thanks to Google and others they showed how to use existing technologies to change the way we access internet based applications. Most of the software giants like Microsoft, Adobe and others are coming out with AJAX based software development toolkits which shows their commitment to the new model of web based applications. Following sections gives references (links) to AJAX technologies and other resources.

Examples: Popular AJAX Applications on the Web

Google Suggest - http://www.google.com/webhp?complete=1&hl=en
Google Maps – http://maps.google.com/
Flickr - http://www.flickr.com/
Odeo - http://odeo.com/
Backpack - http://backpackit.com/
Basecamp - http://basecamphq.com/

RIA - Software Development Kit

Microsoft Atlas: http://atlas.asp.net/
Adobe Macromedia Flex 2.0: http://www.adobe.com/products/flex/
Backbase Ajax Development Framework: http://www.backbase.com/
Tibco General Interface: http://www.tibco.com/software/ria/gi_resource_center.jsp
JackBeNQ Suite : htttp://www.jackbe.com/
Open Source - OpenLaszlo: http://www.openlaszlo.org/

REST – Representational State Transfer
SOAP – Simple Object Access Protocol
AJAX – Asynchronous JavaScript And XML
ECMA – ECMA-262 Specifications
CSS – Cascading Style Sheets

Demo

• Open Source Openlaszlo Demos
• Adobe Macromedia Flex 2.0 Demo 1
• Adobe Macromedia Flex 2.0 Demo 2
• Backbase Demo 1
• JackBe Demo 1
• JackBe Demo 2 Bank

AJAX Blogs

http://www.ajaxian.com/
http://www.ajaxmatters.com/
http://www.ajaxpatterns.org/
http://www.ajaxinfo.com/
http://www.ajaxblog.com/
http://ajaxguru.blogspot.com/

Books

Amazon – AJAX and PHP: Building Responsive Web Applications
Amazon – AJAX in Action
Amazon – AJAX Patterns and Best Practices (Experts Voice)
Amazon – Foundations of AJAX
Amazon – Essential Actionscript 2.0
Amazon – Developing Rich Clients with Macromedia Flex
Amazon – Professional AJAX (Programmer to Programmer)

Resources

AJAX Magazine – W3C Working Draft on the XMLHttpRequest Object
AJAX – Getting Google Calendar Data on your site
Sun – AJAX made easy
Microsoft – AJAX for ASP
Rich Internet Apps - http://theopensourcery.com/xmlria.htm
ECMA Script - http://en.wikipedia.org/wiki/ECMAScript
ECMA International – ECMA Script - 262
ZDNet - RIA Clients: Not just for the web anymore
Java Lobby – RIA and AJAX: Selecting the best product
AJAX Magazine – Yshout a PHP and AJAX powered shoutbox
AJAX Magazine – PHP and AJAX