XEP-0367: Message Attaching

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.

1. Introduction
2. Discovering support
3. Usage
4. Business Rules
5. Security Considerations
6. IANA Considerations
7. XMPP Registrar Considerations
8. XML Schema

Appendices
    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

Many messaging applications send special messages which include more information about a previous message. For example, when sending a link the service may display the description or an image off the page, or users may respond to a message with a "sticker" or an "emotion" which they wish to display alongside the message, even though the conversation has moved on.

This specification defines a way by which one can indicate that a message is logically (and visibly) "attached" to an earlier message in the conversation.

2. Discovering support

If a client implements message attaching, it MUST specify the 'urn:xmpp:message-attaching:0' feature in its service discovery information features as specified in Service Discovery (XEP-0030) [1] and the Entity Capabilities profile specified in Entity Capabilities (XEP-0115) [2].

<iq type='get'
    from='alonso@naples.lit/ship'
    id='miuARo9V'>
  <query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>

<iq type='result'
    to='alonso@naples.lit/ship'
    from='naples.lit'
    id='miuARo9V'>
  <query xmlns='http://jabber.org/protocol/disco#info'>
…
    <feature var='urn:xmpp:message-attaching:0'/>
…
  </query>
</iq>

3. Usage

Messages that are attached to other messages MUST contain an <attach-to/> element qualified by the 'urn:xmpp:message-attaching:0' namespace and with an 'id' attribute set to the ID of the message that we want to attach to. Messages MAY be attached to any other message, including those sent by other clients, but clients MAY choose to ignore the attach-to directive and display the message normally.

<message to='antonio@milan.lit/ship' from='prospero@milan.lit/island id='RgEGnjqy'>
  <body>storm.png</body>
  <attach-to id='oldmessage1' xmlns='urn:xmpp:message-attaching:0'/>
</message>

Note that indicating that a message should be "attached" to an earlier message in the conversation is merely a suggestion to the client to display the message next to or below the old message.

4. Business Rules

A receiving client MAY choose to show the attached message next to or below the indicated message in whatever display is used for messages or can choose to display the attachment in another way (including as a normal message, completely ignoring the attach-to element).

A receiving client SHOULD indicate that the message is an attachment, and not a part of the original message to prevent confusion.

A server may choose to strip some <attach-to/> messages based on local policy (eg. a server might have a policy that only it can create message attachments).

Clients and servers MUST NOT include an <attach-to/> element on messages with a non-messaging payload unless they are including it on an error which may be attached to the message that caused the error to be generated.

5. Security Considerations

Clients that implement message attachments MUST be careful not to display the attachments in such a way that they could be confused with the original message and cause someone viewing the conversation to assume they were sent by the sender of the message being attached to.

6. IANA Considerations

7. XMPP Registrar Considerations

<var>
	<name>urn:xmpp:message-attaching:0</name>
	<desc>Indicates support for attaching one message to another.</desc>
	<doc>XEP-xxxx</doc>
</var>

8. XML Schema

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

<xs:schema
    xmlns:xs='http://www.w3.org/2001/XMLSchema'
    targetNamespace='urn:xmpp:message-attaching:0'
    xmlns='urn:xmpp:message-attaching:0'
    elementFormDefault='qualified'>

  <xs:element name='attach-to'>
    <xs:complexType>
      <xs:simpleContent>
        <xs:extension base='xs:string'>
          <xs:attribute name='id' type='xs:string' use='required'/>
        </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
  </xs:element>

</xs:schema>

Appendices

Appendix A: Document Information

Series: XEP
Number: 0367
Publisher: XMPP Standards Foundation
Status: Experimental
Type: Standards Track
Version: 0.1
Last Updated: 2015-12-15
Approving Body: XMPP Council
Dependencies: XMPP Core
Supersedes: None
Superseded By: None
Short Name: message-attaching
Source Control: HTML
This document in other formats: XML PDF

Appendix B: Author Information

Sam Whited

Email: sam@samwhited.com
JabberID: sam@samwhited.com
URI: https://blog.samwhited.com/

Craig Petchell

Email: cpetchell@atlassian.com

Appendix C: Legal Notices

Copyright

Permissions

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 <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) 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.

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-0030: Service Discovery <https://xmpp.org/extensions/xep-0030.html>.

2. XEP-0115: Entity Capabilities <https://xmpp.org/extensions/xep-0115.html>.

3. The Internet Assigned Numbers Authority (IANA) is the central coordinator for the assignment of unique parameter values for Internet protocols, such as port numbers and URI schemes. For further information, see <http://www.iana.org/>.

4. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>.

Abstract:	This specification defines a method for indicating that a message contains content which describes an earlier message in the conversation and should be grouped with the earlier message.
Authors:	Sam Whited, Craig Petchell
Copyright:	© 1999 – 2017 XMPP Standards Foundation. SEE LEGAL NOTICES.
Status:	Experimental
Type:	Standards Track
Version:	0.1
Last Updated:	2015-12-15