MailMan and Saving Attachments

I'm using the mailmain gem to grab pop3 mail. This library uses the mail gem to break up the message body and attachments. I'm to the point where I can get the attachment in the pry command line like so:

14: Mailman.config.rails_root = '../'
15: 
16: Mailman::Application.run do
17:   to 'expenses@surveymonkey.com' do
18:     require 'debugger'; debugger
=> 19:     print message
20:   end
21: end

and I can get an individual attachment like so

[1] pry(#<Mailman::Router>)> a = message.attachments[0]
=> #<Mail::Part:70339703566060, Multipart: false, Headers: <Content-Type: image/jpeg;   name="70s-Jump-Suit.jpeg">, <Content-Transfer-Encoding: base64>, <Content-Disposition: attachment; filename="70s-Jump-Suit.jpeg"; size=38412; creation-date="Tue, 26 Jun 2012 22:11:10 GMT"; modification-date="Tue, 26 Jun 2012 22:11:10 GMT">, <Content-Description: 70s-Jump-Suit.jpeg>>

So, the question is, how do I save this data?

I'm close with this method, but I'm unable to properly save.

and I've tried stuff like this

[2] pry(#<Mailman::Router>)> File.open( '/tmp/output.jpg', "w+b", 0644 ) { |f| f.write a.raw_source }

but the output gets botched.

I just don't know enough about email encoding to get this to work.

Thanks in advance!

Ah, here we go:

http://cbpowell.wordpress.com/2011/01/17/saving-attachments-with-ruby-1-9-2-rails-3-and-the-mail-gem/

# tmail is now a Mail object
tmail.attachments.each do |tattch|
  fn = tattch.filename
  begin
    File.open( fn, "w+b", 0644 ) { |f| f.write tattch.body.decoded }
  rescue Exception => e
    logger.error "Unable to save data for #{fn} because #{e.message}"
  end
end