N file uploads from one post - one File, (N-1) StringIOs

All,

Win XP
Ruby 1.8.4
Rails 1.1

I have a multipart form that I am posting with a dynamic number of
file_fields that are generated on it, say N.

When I post this form and look at the form params, I see one “File”
object and N-1 “StringIO” objects.

It appears that I should be able to manipulate these the way that I
would like (file-wise), so I think it’s not a problem.

I’ve verified that regardless of the number of file fields N, if N > 1,
then I will get a File object and (N-1) StringIO objects.

Anyone know why I get the StringIO objects and why the first one is a
File?

I’ve looked at the CGI.rb docs and I see that StringIO and Tempfile are
what’s expected. I just wanted to be sure that this was normal
behavior.

Thanks,
Wes