gistfile1.txt

 var promise = fs.readFile(filename, encoding);

    promise.addCallback(function (data) {
      body = data;
      headers = [ [ "Content-Type"   , content_type ]
                , [ "Content-Length" , body.length ]
                ];
      if (!DEBUG)
        headers.push(["Cache-Control", "public"]);
       
      sys.puts("static file " + filename + " loaded");
      callback();
    });

    promise.addErrback(function () {
      sys.puts("Error loading " + filename);
    });