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Web Application Session Tracking

category: database

How do Web-based applications differ from stand-alone applications like your word processor? The basic difference is that Web applications require session tracking in order to duplicate the functionality of your stand-alone applications. What the hell does that mean? Read on.

When you open your word processor, it formats the screen for you and waits. It has done its part, and now it's your turn. If you click the mouse or press the enter key, it responds and then, politely, it waits. You are having a one-on-one conversation with your word processor; therefore there is never any confusion about who is saying what to whom. If you choose the save button, your word processor knows who you are and where to put your document because you are the only user it's talking to. Your word processor is a stand-alone application functioning in conversational mode. If you page back in your document, you will never see page 1 of someone else's letter.

A Web server running a Web application, on the other hand, services your request to view such and such a page, or whatever, and then breaks the connection. It breaks the connection because it's designed to handle a variable number of users at any one time. This is not a problem if your request is simply to view a page once you have clicked a link; however if the Web application is required to duplicate the functionality of a standalone application on your PC, that is have a conversation with you, it must know who you are before it can determine where you were in the conversation. To determine the correct place in the conversation, a Web application keeps notes about your conversation (session) and stores them under your name (session ID) before it breaks the connection. The next time you make a request, do anything, the Web application reads your session ID, stored as a cookie in your browser, restores your conversation from its notes and responds to you appropriately. The Web application is functioning in pseudo conversational mode. Web application session tracking allows a Web application to duplicate the functionality of a stand-alone application functioning in one-on-one conversational mode.

If you want Web applications to work as they were designed to work, don't disable cookies in your browser.

He said on 03.18.05 @ 04:32 PM CST