# Returns all data of a given mime_type from a multipart message
def extract_type(mime_type, multipart_text)
  data = ""   # buffer for holding the returned lines
  begin_boundary = /Content-Type: \S+; boundary=(\S+)/
  end_content = %r{a^}  # (at first, will not match against any value)
  matching_content = false
  multipart_text.each_line do |line|
    if matches = line.match(begin_boundary)
      end_content = %r{--#{matches[1]}}
    end
    matching_content = false if line.match end_content
    data += line if matching_content
    matching_content = true if line.match /Content-Type: #{mime_type}/
  end
  data
end