I switched my server over to lighttpd running on cygwin and implemented your suggestion now that I have access to PIDs. I am just trying to get proof of concept at the moment, and I am running into a little problem. I fork my upload cgi script to create a text file with the PID of the upload script in a separate process.

The cancel cgi script is reading the PID just fine, but the problem is that even though I am forking the upload process, that text file isn't showing up/being created for awhile after the "upload" button is pressed. I am waiting in the parent upload process and put a sleep on the child process(write text file with PID), but it still takes awhile for that text file to show up. Obviously if you click the Cancel button within a second or two of starting, it throws an error, because that file isnt there yet.

Is this a problem that could be helped by using FastCGI?