Re: Howto implement atomical actions

On Sat, June 11, 2005 6:46 am, Andy Pieters said: > I am developing a web interface to patch a program. The user uploads the > patch and after uncompressing and verification of signature, the update > should take place. However I do not want users to be able to start an > update > and then abort the process by stopping to load the page. > > I imagine that by calling a program externally from php that it would be > possible but there are limitations because of the distribution. The > systems > are installed on php+mysql+apache servers but no shell access is granted. Perhaps it would be best to take PHP out of the picture entirely after the upload. For example, upload to a temporary directory, and, as your last PHP step, use http://php.net/rename to move the uploaded file to a "to_be_installed" directory. Then you can have cron job 2 minutes that installs anything it finds in that directory. At that point, nothing the user can do can interfere. That wouldn't necessarily make the operation atomic... What makes a "patch" atomic?... You'd be looking at something like subversion for that, I should think... I don't think even tar -xzf guarantees atomicity, but I dunno. -- Like Music? http://l-i-e.com/artists.htm