I'm writing a web application that, among other things, allows users to upload files to my server. In order to prevent name clashes and to organize the files, I rename them once they are put on my server. By keeping track of the original file name I can communicate with the file's owner without them ever knowing I changed the file name on the back end. That is, until they go do download the file. In that case they're prompted to download a file with a unfamiliar name.
My question is, is there any way to specify the name of a file to be downloaded using just HTML? So a user uploads a file named 'abc.txt' and I rename it to 'xyz.txt', but when they download it I want the browser to save the file as 'abc.txt' by default. If this isn't possible with just HTML, is there any way to do it?