Typical AJAX = Client Server
AJAX client side is similar to client-server computing, because it shifts much of the application logic to the client. It allows experienced javascript developers for applications that access the Internet and the computer they run on the development, during the liberation of the servers that do not focus on UI tasks. Client-side AJAX application shows that flow and UI logic will be developed in conjunction with DHTML and JavaScript to connect to any server-side
Failed, the trend towards AJAX has on businesses and the line of business applications. The developers are constantly trying to cope with ever-growing demand while improving the overall user experience. However, AJAX is a new challenge when they are used in the company, submitted.: Securing direct connections between client and server
On Server AJAX = On Server computing
The On-Server AJAX paradigm shift is lead by Visual WebGui.
The approach, marked by Guy Peled as
On-Server AJAX, opens the path for enterprises to enjoy the AJAX evolution benefits
Server based computing platforms such as Citrix and Windows Terminal Services have grown in popularity as a result of no alternatives means of supporting heavy deployments of client-server line of business applications over web. Their costs are accordingly. On-Server AJAX paradigm shift allows for the first time, to support deployments of complex AJAX line of business applications in unprecedented simplicity, by-design security, no-limit complexities all at dramatically reduced costs.
Eliminating the security hazard, facilitating enterprises usage
Client side AJAX requires the browser to connect directly to a web service or even a raw data provider. Since this is a very dangerous practice, developers usually connect to a proxy application service which understands the “context” of the request by recalling session state. There are numerous articles discussing the security challenges presented by client side AJAX. For consumer internet sites, the improved user experience has usually overridden the security concerns. However, for enterprise applications this is still a key concern.
On-Server AJAX utilizes a client side “rendering” engine which communicates with the server over XMLHttp. The rendering engine uses a proprietary protocol to incrementally update the view. The client never consumes data or services directly since all of the application logic, UI logic and data access is handled on the server. The client simply connects to the “view” on the server and therefore never compromises security. Furthermore, since a proprietary protocol is used to correlate view state between the server and the client, it’s a greater challenge to override, eavesdrop or hack.
In addition in On -Server AJAX, the only data that is delivered to the client is data that can be viewed on the client meaning there is never any sensitive data that may be required for logic or validation beyond what is rendered and seen by the user on the screen.
Developer Productivity in building complex enterprise level GUIs, as never before
While AJAX has brought a significant improvement in user experience and application complexity, it has also brought about a dramatic increase in the complexity of development and testing. Furthermore it requires developers to a number of different languages: Javascript, HTML, CSS and XML on the client as well as the server side language being used to develop the underlying business logic.
A complex web application such as Microsoft Outlook Web Access or Salesforce.com also requires serious architecting skills in order to maintain application state, security and data integrity between local cached data and server side data. While historical, page based web applications were deemed easier and cheaper to develop then their desktop counterparts, developing a complex client based AJAX web application is harder and more expensive to develop then an equivalent client-server application.
On-Server AJAX paradigm shift enables the developer to use a single language and programming model in order to design the application UI and the underlying logic. In addition it alleviates the need to understand and deal with the web’s innate statelessness. Instead On-Server AJAX offers the use of well known design patterns and tools such as WinForms to design and develop highly interactive, data rich applications with the same productivity of desktop applications.
Simplifying the architecture from a loosely coupled, stateless, multi-language/technology into a tightly coupled, object oriented, single language environment means less time is spent on architecture, development, debugging and maintenance ultimately improving ROI and TCO. In addition the layout and interaction design are not as limiting as most web oriented application development platforms.
On-Server AJAX developers also enjoy re-use of well honed skills (WinForms) and existing code which further improves productivity.
For technological Gurus opinion on On-Server AJAX productivity see:
MS MVP RICK STRAHNL on his blog: “Visual WebGui is intriguing. It’s ridiculous how productive you can be with a tool like this compared to building an ASPX page. But somehow it feels like cheating…”. ” http://west-wind.com/weblog/posts/180727.aspx
MVP ROY OSHOROVE on his blog:” “…Visual WebGui can help change the web development world and make it more usable, reachable and easier than ever…” http://weblogs.asp.net/rosherove/archive/2007/07/28/visual-web-gui-helps-me-write-in-winform-and-run-as-asp-net.aspx
Highly optimized performance (purely desktop’s) and user experience
Client side AJAX is meant to improve the responsiveness of the client. In most cases the user experience is improved, however it can have a dramatic effect on server load. Frameworks send across hundreds of lines of Javascript code over and over between requests, necessitating heavy I/O on the host web server generating a “large” bandwidth profile. Client side AJAX frameworks rely on the processing power of the client to handle caching, serialization, validation and paging. Performance varies according to the available resources on the client. Lower memory and slower CPUs could have an adverse effect on the user experience.
On- Server AJAX only need to transfer the rendering engine code once and then transfer state and data changes as required. Ultimately they require more client/server round trips; however their bandwidth profile is kept at a minimum. This results in a highly responsive application which utilizes fewer resources by the server enabling it to handle more concurrent users. In On-Server AJAX the client only handles rendering of the current view state. This means that less client side objects and data need to be processed on the client (for rendering purposes) resulting in less client side resources being required. Ultimately this ensures all users receive uniform performance regardless of their memory and CPU limitations.
MS MVP WIKTOR ZYCHLA on his blog: ‘ VWG is the undoubted winner it did a great job of serving the highest number of requests per second”
http://netpl.blogspot.com/2007/06/aspnet-ajax-framework-contest.html
Summary
As more and more applications in turn support the Internet as the de-facto deployment platform, the need for tools to grow and development on complex surfaces. AJAX is a key component of modern web applications and will continue to serve as the basis for many rich Internet applications. AJAX is just an expression, there are plenty of AJAX technologies and techniques available, and not all are created equal. As a whole, On-Server AJAX paradigm shift led by Visual WebGui provides a better way to design and develop complex, secure, robust applications in an effective and familiar way.
For samples of applications built on On-Server AJAX see:
http://www.visualwebgui.com/Community/Forum/tabid/53/forumid/-1/threadid/5247/scope/posts/Default.aspx
Bibliography:
“Cognitive Load and the Superiority of Server-Side Ajax GUI Frameworks”
http://blogs.pathf.com/agileajax/2006/08/cognitive_load_.html
“Attacking AJAX Web Applications” – Alex Stamos, Zane Lackey iSEC – http://www.isecpartners.com/files/iSEC-Attacking_AJAX_Applications.BH2006.pdf
“Ajax (programming)” – Wikipedia
http://en.wikipedia.org/wiki/Ajax_(programming)
“Server –Side AJA X for the Enterprise”
http://www.adtmag.com/article.aspx?id=21111
“What’s Ajax”
http://ajaxpatterns.org/Whats_Ajax
“Ajax alert raises security, scalability issues”
http://searchsoa.techtarget.com/originalContent/0,289142,sid26_gci1162641,00.html
