How to serve files in Drupal without using links?

Question

How do I serve files in Drupal without revealing a link that might be re-used? This sort of thing is usually handled by postbacks in .NET for example, but I can't find any documentation for accomplishing it in Drupal.

The goal is to be able to give a specific file to a user exactly once when they complete a series of steps defined by the module. Some of the eCommerce modules provide some features to support limited file downloads, but I would prefer not to install an entire eCommerce solution just to accomplish one task.

Thanks in advance!

Answer 1

You can do it at the web server level, saving on the drupal code+db load: for example with lighttpd you can use the mod-trigger-b4-dl module to have limited validity urls, either using an interstitial or a validation callback in drupal.

See mod trigger b4 dl docs for details

Answer 2

You would write a module to manage the one-time URLs and log when they have been accessed.

The module would use the PHP fread() function to serve the file from some private location.