From: khaines@...
Date: 2006-08-11T16:01:12+09:00
Subject: Re: Getting a files mime-type

On Fri, 11 Aug 2006, Daniel Greig wrote:

> Can anyone tell me if there is a simple way to get the mime-type of a
> file?
> (I've seen the Mime::Type library, but haven't figured out how to use
> it).
> I'm trying to check the type before processing a bunch of files on disk
> (and ignoring files that I'm not interested in. Is there a better way
> than using the file extension?

MIME::Types.type_for(filename)

Using a file extension is fast.  It's what MIME::Types does.  It obviously 
doesn't work if the extension doesn't match the file type, though.

The alternative is to use a heuristic that identifies distinct 
characteristics of different file types in order to guess at the type. 
This can identify the type of a file when the extension doesn't match the 
type, but it isn't necessarily 100% certain, either.

If you have Apache, look in the conf directory for a 'magic' file. 
mod_mime_magic uses that to perform type guessing.  I am unaware of a mime 
magic library for Ruby at this time, but if anyone knows of one, I'd love 
to be pointed towards it.


Kirk Haines