Current way to download large files in rails
===

I used to use the method outlined by Obie Fernandez to download files: 

http://www.therailsway.com/2009/2/22/file-downloads-done-right/

But this way is a bit outdated so curious what is better?  My fear is if you have multiple clients downloading large files too much memory would be eaten up.

I need to camo the S3 url and control who can download what.  Perhaps this method is still fine or maybe streaming is the way to go.

Thanks in advance.