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Message Stanza Profiles This document specifies best practices for generating and handling extended content in XMPP message stanzas. &LEGALNOTICE; 0226 Experimental Informational Standards Council N/A &infiniti; &stpeter; 0.1 2007-08-08 psa

Initial published version; specified more granular profiles; renamed transmission elements to metadata elements.

 0.0.2 2007-08-01 psa

Clarified that message profiles apply to sending entities as well as receiving entities.

 0.0.1 2007-08-01 jk/psa

First draft.

The definition of XMPP stanzas in &xmppcore; and &xmppim; allows a &MESSAGE; stanza to include any number of child elements that define extended content. The fact that a message stanza may contain multiple instances of extended content can make it difficult for sending entities to know what is appropriate for inclusion in a message stanza and for receiving entities to know exactly how to process a message stanza.

Consider the following hypothetical example, which as we shall see is invalid.

Shall we meet?

Shall we meet?

romantic_meetings
high
 Italy 45.44 Venice 12.33 ]]>

What to make of a message like this? The import seems to be that Romeo, being in a flirtatious mood (&xep0107;) and currently located near Juliet's abode (&xep0080;), would urgently (&xep0131;) like to meet with Juliet (message body) and proposes two convenient places (&xep0020;) for an evening tryst, but no later than midnight (&xep0079;). But how is Juliet's client supposed to figure that out? That is, what should her client present to the user? And should Romeo's client even send a monstrosity such as this? (No.)

To clarify such matters, in this document we introduce the concept of "message stanza profiles".

We propose the following profiles.

The instant messaging (IM) profile is the "default" profile for message stanzas. For example, if a message stanza includes only elements that are defined for the 'jabber:client' namespace then it is in the IM profile. If a message stanza includes both IM profile elements and other elements, the IM elements should be considered a fallback and the profile should be determined based on the other elements if supported (e.g., a data form). A sending entity should limit the elements it includes to IM profile elements, unless the IM elements are a fallback.

The extended content defined in the following specifications is considered to be in the IM profile:

  • &xmppim;
  • &xep0045; (e.g., invitations)
  • &xep0066;
  • &xep0071;
  • &xep0085;
  • &xep0144;
  • &xep0172;

Extended content elements defined in &xep0004; are considered to be in the Data Forms profile.

Extended content elements defined in &xep0009; are considered to be in the RPC profile.

Extended content elements defined in &xep0020; are considered to be in the Feature Negotiation profile.

Extended content elements defined in &xep0070; are considered to be in the HTTP Authentication profile.

Extended content elements defined in &xep0072; are considered to be in the SOAP profile.

Extended content elements defined in &xep0155; are considered to be in the Stanza Session Negotiation profile.

Metadata elements are included to define how the message stanza shall be routed, delivered, or processed in transit. Metadata elements shall not be used to determine which profile applies. If a message stanza includes only metadata elements, it can be considered to have no profile.

The extended content elements defined in the following specifications are considered to be metadata elements:

We stipulate the following rules:

  1. A single profile applies to each message stanza (i.e., a message is not in two or more profiles).
  2. Transmission elements do not affect the profile.
  3. Each element is part of some profile. Unless otherwise stated, the same profile applies to every element of a given namespace.
  4. Unknown elements have no affect on determining the profile.
  5. When determining which profile applies to a stanza, consider the IM profile as a last resort.
  6. A sending entity must not mix profiles, except IM profile elements may included with with any other profile as a fallback (e.g., a message body along with a data form).

Therefore, the example provided in the introduction should never be generated by a sending client because the message combines multiple profiles. If it receives a message stanza that combines multiple profiles, the receiving client MAY return a stanza error, which SHOULD be ¬acceptable;.

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This document adds no security concerns or consideration above and beyond those specified in the specifications to which it refers.

This document requires no interaction with &IANA;.

A future version of this specification may call for the ®ISTRAR; to establish a registry of message stanza profiles, so that each relevant specification shall define which profile applies to extended content qualified by the relevant namespace.