gistfile1.rb

# add a utility method 'set_file'
module Technoweenie
  module AttachmentFu
    module InstanceMethods
      def set_file(path, content_type = Mime::TEXT)
        raise ArgumentError, "No such file - #{path}" unless File.exists?(path)
        self.filename = File.basename(path)
        self.content_type = content_type
        set_temp_data File.read(path)
      end
    end
  end
end