# File lib/cgikit/resource.rb, line 451
  def set_data( data, key, mime )
    unless FileTest.directory? @tmpdir
      require 'ftools'
      File.makedirs @tmpdir
    end
    cache = {}
    cache[:data] = data
    cache[:key]  = key
    cache[:mime] = mime
    FileLock.exclusive_lock(tmpfile(key)) do |file|
      Marshal.dump(cache, file)
    end
  end