Detecting MIME type of a shared file

[James Simmons]

I am working on adding sharing code to the Read Etexts activity, mostly 
adapting existing code from the core Read activity.  Read ETexts can 
open ascii text files and zip files that contain a single text file.  I 
look at the suffix of the filename to tell what kind of file I'm dealing 
with.  This works just fine when I download the file using the Browse 
activity, but when I share the file the computer receiving the file gets 
a random filename with no suffix.  At least that's what I *think* is 
happening, as my sugar-jhbuild is not fully functional yet.  So the 
question is, how can I tell what kind of file I am receiving when 
someone shares a file with me?

Thanks,

James Simmons