XEP-0297: Message Forwarding

Abstract:This document defines a protocol to forward a message from one entity to another.
Authors:Matthew Wild, Kevin Smith
Copyright:© 1999 - 2011 XMPP Standards Foundation. SEE LEGAL NOTICES.
Type:Standards Track
Last Updated:2011-04-11

WARNING: This Standards-Track document is Experimental. Publication as an XMPP Extension Protocol does not imply approval of this proposal by the XMPP Standards Foundation. Implementation of the protocol described herein is encouraged in exploratory implementations, but production systems are advised to carefully consider whether it is appropriate to deploy implementations of this protocol before it advances to a status of Draft.

Table of Contents

1. Introduction
2. Requirements
3. Forwarding a message
    3.1. Overview
    3.2. Business rules
4. Security Considerations
5. XML Schema
6. Acknowledgements

    A: Document Information
    B: Author Information
    C: Legal Notices
    D: Relation to XMPP
    E: Discussion Venue
    F: Requirements Conformance
    G: Notes
    H: Revision History

1. Introduction

There are many situations is which an entity needs to forward a previously sent message to another entity, such as forwarding an interesting message to a friend, or a server forwarding stored messages from an archive. Here we specify a simple encapsulation method for such forwarded messages.

2. Requirements

Several properties are desirable when forwarding messages:

3. Forwarding a message

3.1 Overview

Let us suppose that a Romeo receives a message from Juliet:

Example 1. Receiving a message

      <message to='romeo@montague.lit' from='juliet@capulet.lit/orchard' type='chat' id='0202197'>
        <body>Yet I should kill thee with much cherishing.</body>
        <mood xmlns='http://jabber.org/protocol/mood'>

To forward this to Mercutio, Romeo would send a new message with a <forwarded/> payload of namespace 'urn:xmpp:forward:tmp'.

Example 2. Forwarding a message

      <message to='mercutio@verona.lit' from='romeo@montague.lit/orchard' type='chat' id='28gs'>
        <body>A most courteous exposition!</body>
        <forwarded xmlns='urn:xmpp:forward:tmp'>
          <delay xmlns='urn:xmpp:delay' stamp='2010-07-10T23:08:25Z'/>
          <message to='romeo@montague.lit' from='juliet@capulet.lit/orchard' type='chat' id='0202197' xmlns='jabber:client'>
              <body>Yet I should kill thee with much cherishing.</body>
              <mood xmlns='http://jabber.org/protocol/mood'>

3.2 Business rules

4. Security Considerations

Forwarding messages can reveal information about the original sender, including possible presence leaks as well as the message payloads themselves. Any extensions using this format must therefore consider the implications of this.

Receipt of a forwarded message from a third-party does not guarantee that the original message was actually received, or that the content has not been modified, by the forwarder. Integrity of the original message can only be determined through digital signing mechanisms such as described in Encapsulating Digital Signatures in XMPP [3] and Encapsulated Digital Signatures in XMPP [4].

Considering the above an end-user client should take special care in its rendering of a forwarded message to ensure that the user cannot mistake it for a message received directly from the original sender.

5. XML Schema

<?xml version='1.0' encoding='UTF-8'?>


      The protocol documented by this schema is defined in
      XEP-xxxx: http://www.xmpp.org/extensions/inbox/forwarding.html

  <xs:element name='forwarded'>
      <xs:sequence xmlns:delay='urn:xmpp:delay'>
        <xs:element ref='delay:delay' minOccurs='0' maxOccurs='1' />
        <xs:any namespace='##other' minOccurs='1' maxOccurs='1' />


6. Acknowledgements

Thanks to Florian Zeitz for feedback.


Appendix A: Document Information

Series: XEP
Number: 0297
Publisher: XMPP Standards Foundation
Status: Experimental
Type: Standards Track
Version: 0.1
Last Updated: 2011-04-11
Approving Body: XMPP Council
Dependencies: XMPP Core
Supersedes: None
Superseded By: None
Short Name: forwarding
Schema: <>
Source Control: HTML
This document in other formats: XML  PDF

Appendix B: Author Information

Matthew Wild

Email: me@matthewwild.co.uk
JabberID: me@matthewwild.co.uk

Kevin Smith

Email: kevin@kismith.co.uk
JabberID: kevin@doomsong.co.uk

Appendix C: Legal Notices


This XMPP Extension Protocol is copyright © 1999 - 2011 by the XMPP Standards Foundation (XSF).


Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <http://xmpp.org/extensions/ipr-policy.shtml> or obtained by writing to XMPP Standards Foundation, 1899 Wynkoop Street, Suite 600, Denver, CO 80202 USA).

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 3920) and XMPP IM (RFC 3921) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.

Appendix E: Discussion Venue

The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.

Discussion on other xmpp.org discussion lists might also be appropriate; see <http://xmpp.org/about/discuss.shtml> for a complete list.

Errata can be sent to <editor@xmpp.org>.

Appendix F: Requirements Conformance

The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".

Appendix G: Notes

1. XEP-0085: Chat State Notifications <http://xmpp.org/extensions/xep-0085.html>.

2. XEP-0203: Delayed Delivery <http://xmpp.org/extensions/xep-0203.html>.

3. XEP-0285: Encapsulating Digital Signatures in XMPP <http://xmpp.org/extensions/xep-0285.html>.

4. XEP-0290: Encapsulated Digital Signatures in XMPP <http://xmpp.org/extensions/xep-0290.html>.

Appendix H: Revision History

Note: Older versions of this specification might be available at http://xmpp.org/extensions/attic/

Version 0.1 (2011-04-11)

Initial published version.


Version 0.0.1 (2011-03-22)

First draft.