Solving web replication conflict problems?08:26:35 AMYesterday I finished my latest Lotus Advisor article, the fifth in my series on AJAX in the Domino world. 
In this one, thanks to some much-appreciated help from Henry Newberry, I solved what I think may be an as-yet unsolved issue with Domino web applications: Preventing multiple people from editing the same document at once.
The problem, as you may know, is the web is stateless. That is, it's not like the Notes client where, except when the client or Windows crashes, there are recognizable events when you both open and close a document. Using those events (Query- and PostOpen, QuerySave, QueryClose), you can build mechanisms into Notes applications to keep two people from editing the same document at the same time (assuming a few things: They're on the same server, etc.).
We've been doing this in ProcessIt! for many years now.
Heck, with R6, Lotus added this capability into the standard Notes client so even mortals could get this stuff working for client-based applications. But, as far as I know, there are still no solutions to this from the web. The problem is, once the server sends its stream of code down to the client, it goes on to other things. It has no way of knowing whether you're still there or not.
Maybe more to the point, you, as a user, can leave the Domino page in your browser at any time to do whatever it is you're doing when your boss isn't looking. When you ditch the work you were supposed to be doing to go search eBay for trinkets and trash, the server has no idea you're not there anymore. Consequently, it doesn't know whether to allow me to edit the document you were "working" on eariler.
Well, we've solved the problem using a little AJAX and a simple Notes agent. It's easily portable to other applications, runs quickly and...turned out really great. To find out more, look for the September 2006 issue of Lotus Advisor.
1. Joachim06/28/2006 06:10:32 PM
Homepage: http://domino.dagerot.com
For sure one of the most common problems when building collaboration sites. I'm certainly looking forward for the next Advisor issue!
2. Mahesh11/20/2008 07:37:55 AM
I want how to prevent the save conflict in web applications..plz help me
3. Scott Good11/20/2008 08:36:26 AM
Homepage: http://www.scottgood.com
Hi Mahesh,
Get a copy of the September 2006 Advisor or get access to it on-line. Details are there.
Scott
