Special characters in attachment file names

(function processStageToRequest(request, stage, transaction, message, bond, scratchpad) {

  // This information would normally come from the AttachmentSender
  var sender = new x_snd_eb.AttachmentSender(transaction, bond);
  sender.next();

  var file_name = sender.attachment_name;
  var mime_type = sender.attachment_type;
  var attach_id = sender.attachment_id;


  //-----------------------
  // Path construction
  //-----------------------
  scratchpad.file_name = encodeURI(file_name);
  scratchpad.reference = stage.external_reference;

  // ?file_name=${scratchpad.file_name}&reference=${scratchpad.reference}

  //-----------------------
  // Headers construction
  //-----------------------

  // Compose the scratchpad headers and payload
  scratchpad.headers = {
    "Content-Type": mime_type
  };

  //-----------------------
  // Payload construction
  //-----------------------

  // This is the string that triggers attachment streaming outbound
  payload = 'sys_attachment:' + attach_id;

})(request, stage, transaction, message, bond, scratchpad);