xeps/xep-0256.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE xep SYSTEM 'xep.dtd' [
  <!ENTITY % ents SYSTEM 'xep.ent'>
%ents;
]>
<?xml-stylesheet type='text/xsl' href='xep.xsl'?>
<xep>
<header>
  <title>Last Activity in Presence</title>
  <abstract>This specification defines a way to use the Last Activity extension in XMPP presence notifications.</abstract>
  &LEGALNOTICE;
  <number>0256</number>
  <status>Proposed</status>
  <type>Standards Track</type>
  <sig>Standards</sig>
  <dependencies>
    <spec>XMPP Core</spec>
    <spec>XMPP IM</spec>
    <spec>XEP-0012</spec>
  </dependencies>
  <supersedes/>
  <supersededby/>
  <shortname>N/A</shortname>
  &stpeter;
  <revision>
    <version>0.1</version>
    <date>2008-11-26</date>
    <initials>psa</initials>
    <remark><p>Initial published version; removed note about handling the absence of a last activity notation; added security considerations.</p></remark>
  </revision>
  <revision>
    <version>0.0.1</version>
    <date>2008-11-20</date>
    <initials>psa</initials>
    <remark><p>Rough draft based on list discussion.</p></remark>
  </revision>
</header>
<section1 topic='Use Case' anchor='usecase'>
  <p>&xep0012; defines a method for determining the last time that an XMPP entity was active. This document specifies that an online client MAY include last activity information when sending presence updates. The prototypical use case is including the idle time when automatically setting the user's &SHOW; value to "away" or "xa" (extended away). For example, consider a user who has configured her client to automatically change her presence to "away" after 10 minutes of inactivity. The client could include an iq:last flag to specify how long the user has been idle.</p>
  <example caption='Last Indication in Auto-Away'><![CDATA[
<presence from='juliet@capulet.com/balcony'>
  <show>away</show>
  <query xmlns='jabber:iq:last' seconds='600'/>
</presence>
  ]]></example>
  <p>If one of the user's contacts receives that presence notification with delayed delivery (see &xep0203;) on login in response to a presence probe as described in &xmppim;, the contact will then know how long the user has been idle (i.e., the number of seconds since the delayed delivery timestamp, plus the iq:last seconds). Thus the contact does not need to send an iq:last query.</p>
  <example caption='Last Indication in Auto-Away With Delayed Delivery'><![CDATA[
<presence from='juliet@capulet.com/balcony' to='romeo@montague.net'>
  <show>away</show>
  <query xmlns='jabber:iq:last' seconds='600'/>
  <delay xmlns='urn:xmpp:delay'
     from='capulet.com'
     stamp='2002-09-10T23:41:07Z'/>
</presence>
  ]]></example>
</section1>
<section1 topic='Security Considerations' anchor='security'>
  <p>Including a last activity notation in presence notifications can enable those who receive such notifications to determine exactly when a user has stopped interacting with his or her XMPP client, but this information is in essence already available if the user publishes timely presence updates. Therefore, this specification introduces no new vulnerabilities.</p>
</section1>
<section1 topic='IANA Considerations' anchor='iana'>
  <p>This document requires no interaction with &IANA;.</p>
</section1>
<section1 topic='XMPP Registrar Considerations' anchor='registrar'>
  <p>This document requires no interaction with the &REGISTRAR;.</p>
</section1>
</xep>