Rick Schummer wrote: >>> I wouldn't dream of running the app on the server anymore, ever since 1999 >>> when I learned about > the LOADER idea from others here on ProFox.<< > > So how do you ensure the user is running the loader and not the local EXE? > Have you taken the > precaution of adding versioning logic to the app startup and every operation > to make sure they are > all running the latest and greatest? It is a common flaw in the loader > approach and one I have been > burned on when taking over projects from other developers. I often see the > recommendation to move to > this approach, but rarely see people explain some of the pitfalls. I am not > saying it is a bad > approach, all I am saying is it has its flaws and overhead to consider.
You can't merely implement a loader, as you've explained. You also have to have: + app checking the version and refusing to start if it isn't the right version. + app checking to see if there's an update to the loader program + some mechanism to ensure the application reloads within a reasonable timeframe after the new app was uploaded. Point #3 I rarely use, because usually these days I'm fixing a bug or adding a feature everyone wants, but I can send a message to all running apps by dropping a command file on the server with things like "shutdown 10" to shut down the application in 10 minutes. At that point, the user gets a modeless always-on-top window telling them to finish up and a countdown to when the app will close itself. So yeah, these things need to be thought about in advance, but I've had this architecture for about a decade now and haven't had any issues to speak of. For a 24/7 app, you'd want to use some variation on the loader that would spawn a new process for the new app while the old version was still running; once the new one was loaded and in place then you'd kill the old. But I can't see how that would work if people were running the exe off the server. Paul _______________________________________________ Post Messages to: ProFox@leafe.com Subscription Maintenance: http://leafe.com/mailman/listinfo/profox OT-free version of this list: http://leafe.com/mailman/listinfo/profoxtech Searchable Archive: http://leafe.com/archives/search/profox This message: http://leafe.com/archives/byMID/profox/[EMAIL PROTECTED] ** All postings, unless explicitly stated otherwise, are the opinions of the author, and do not constitute legal or medical advice. This statement is added to the messages for those lawyers who are too stupid to see the obvious.
