XEP-0224: Attention

This document defines an XMPP protocol extension for getting the attention of another user.

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 should not deploy implementations of this protocol until it advances to a status of Draft.

Document Information

Author Information

Andreas Monitzer

Email: andy@monitzer.com
JabberID: andy@monitzer.com

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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.

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## 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. In no event shall the XMPP Standards Foundation or the authors of this Specification be liable for any claim, damages, or other liability, whether in an action of contract, tort, or otherwise, arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification. ##

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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 out of the use or inability to use 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 may be found at <http://www.xmpp.org/extensions/ipr-policy.shtml> or obtained by writing to XSF, P.O. Box 1641, Denver, CO 80201 USA).

Discussion Venue

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.

Conformance Terms

The following 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".

1. Introduction
2. Requirements
3. Protocol
4. Business Rules
5. Determining Support
6. Implementation Notes
7. Security Considerations
8. IANA Considerations
9. XMPP Registrar Considerations
9.1. Protocol Namespaces
10. XML Schema
11. Acknowledgements
Notes
Revision History

1. Introduction

Even though a client might be available (as stated in the most recent presence stanza) the user this client belongs to might not have the focus on the client currently. Presence Obtained via Kinesthetic Excitation (POKE) [1] defines a method for a physical test of user presence. Since this requires special hardware that can not be assumed to be available, this XEP defines a software-only implementation where no direct feedback is expected. This is known as 'nudge' or 'buzz' in some legacy IM protocols.

It was discussed whether this should be part of Chat State Notifications [2]. However, the semantics are inherently different, since it describes the sender's state, not a request to change the receiver's. Thus, a separate extension is desirable.

2. Requirements

The specification addresses remotely getting the user's attention in a more assertive way than simple text messages.

3. Protocol

In the following conversation, a user talks to somebody, but this user doesn't respond. The second inquiry includes an attention extension.

<message from='calvin@usrobots.lit/lab' to='herbie@usrobots.lit/home' type='chat'>
  <body>All right, then, Herbie, give! We're waiting.</body>
</message>

When no reply is received, the sending user might want to grab the other's attention. This is done by sending a message that includes an <attention/> element qualified by the 'http://www.xmpp.org/extensions/xep-0224.html#ns' namespace (see Protocol Namespaces regarding issuance of one or more permanent namespaces). Note: The message may or may not include a <body/> element.

<message from='calvin@usrobots.lit/lab' to='herbie@usrobots.lit/home' type='headline'>
  <attention xmlns='http://www.xmpp.org/extensions/xep-0224.html#ns'/>
  <body>Why don't you answer, Herbie?</body>
</message>

<message from='herbie@usrobots.lit/home' to='calvin@usrobots.lit/lab' type='chat'>
  <body>I cannot. You know I cannot! Dr. Bogert and Dr. Lanning don't want me to.</body>
</message>

4. Business Rules

The following rules apply to generating and processing of the attention extension.

5. Determining Support

If an entity supports receiving the attention extension, it MUST advertise that fact in its responses to Service Discovery [4] information ("disco#info") requests by returning a feature of "http://www.xmpp.org/extensions/xep-0224.html#ns":

<iq type='get' 
    from='calvin@usrobots.lit/lab'
    to='herbie@usrobots.lit/home'
    id='disco1'>
  <query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>

<iq type='result' 
    from='herbie@usrobots.lit/home'
    to='calvin@usrobots.lit/lab'
    id='disco1'>
  <query xmlns='http://jabber.org/protocol/disco#info'>
    ...
    <feature var='http://www.xmpp.org/extensions/xep-0224.html#ns'/>
    ...
  </query>
</iq>

In addition, support for receiving attention extensions in message stanzas can be determined through the dynamic profile of Service Discovery defined in Entity Capabilities [5].

6. Implementation Notes

However, since some users might not want this feature to disturb them, a client SHOULD enable the user to disable support. When the feature is disabled, it MUST NOT be advertised in disco#info.

Formal feedback in response to the attention request to the requesting user is not specified, and so the request might be silently dropped.

7. Security Considerations

It is recommended that only message stanzas containing attention extensions from peers on the user's roster are accepted. Finer grained control might be implemented.

8. IANA Considerations

9. XMPP Registrar Considerations

9.1 Protocol Namespaces

Until this specification advances to a status of Draft, its associated namespace shall be "http://www.xmpp.org/extensions/xep-0224.html#ns"; upon advancement of this specification, the XMPP Registrar [7] shall issue a permanent namespace in accordance with the process defined in Section 4 of XMPP Registrar Function [8].

10. XML Schema

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

<xs:schema
    xmlns:xs='http://www.w3.org/2001/XMLSchema'
    targetNamespace='http://www.xmpp.org/extensions/xep-0224.html#ns'
    xmlns='http://www.xmpp.org/extensions/xep-0224.html#ns'
    elementFormDefault='qualified'>

  <xs:element name='attention' type='empty'/>

  <xs:simpleType name='empty'>
    <xs:restriction base='xs:string'>
      <xs:enumeration value=''/>
    </xs:restriction>
  </xs:simpleType>

</xs:schema>

11. Acknowledgements

The quotes have been taken from Isaac Asimov's short story "Liar!" as published in the book The Complete Robot.

Notes

1. XEP-0132: Presence Obtained via Kinesthetic Excitation (POKE) <http://www.xmpp.org/extensions/xep-0132.html>.

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

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

4. XEP-0030: Service Discovery <http://www.xmpp.org/extensions/xep-0030.html>.

5. XEP-0115: Entity Capabilities <http://www.xmpp.org/extensions/xep-0115.html>.

6. 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/>.

7. 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 <http://www.xmpp.org/registrar/>.

8. XEP-0053: XMPP Registrar Function <http://www.xmpp.org/extensions/xep-0053.html>.