Here is the concept:
A user has options: Red, Green, and Blue
If the user pick "Red", a file will be created, "Red" is written to it, and then the file is offered to be download.
Here is what I come up with by myself. If you guys know better method, let me know. Also let me know if my system could potentially be abused.
I will allow, say, 10 downloads at a time. So I'm gonna have file01-file10. When user enters his selection, I'm gonna check if there is a file among the ten that is not opened. If there is, selection is written to the file and offered to be downloaded. If not, prompt to try again later.
The filename has to be the same. So my quick and dirty solution is to create each of the ten files in ten different folders. Any thoughts?