xeps/xep-0091.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>Delayed Delivery</title>
  <abstract>This specification provides canonical documentation of the jabber:x:delay namespace currently used within the Jabber community.</abstract>
  &LEGALNOTICE;
  <number>0091</number>
  <status>Active</status>
  <type>Historical</type>
  <sig>Standards</sig>
  <approver>Council</approver>
  <dependencies>
    <spec>XMPP Core</spec>
  </dependencies>
  <supersedes/>
  <supersededby/>
  <shortname>x-delay</shortname>
  <schemaloc>
    <url>http://www.xmpp.org/schemas/x-delay.xsd</url>
  </schemaloc>
  &stpeter;
  <revision>
    <version>1.2</version>
    <date>2004-08-17</date>
    <initials>psa</initials>
    <remark>Specified that the timezone is to be understood as UTC; specified security considerations; corrected several small textual errors.</remark>
  </revision>
  <revision>
    <version>1.1</version>
    <date>2004-02-24</date>
    <initials>psa</initials>
    <remark>Corrected several small textual errors.</remark>
  </revision>
  <revision>
    <version>1.0</version>
    <date>2003-10-08</date>
    <initials>psa</initials>
    <remark>Per a vote of the Jabber Council, changed status to Active.</remark>
  </revision>
  <revision>
    <version>0.1</version>
    <date>2003-05-22</date>
    <initials>psa</initials>
    <remark>Initial version.</remark>
  </revision>
</header>
<section1 topic='Introduction' anchor='intro'>
  <p>The Jabber protocols have long included a method for indicating that a message or presence stanza was delayed in being delivered (e.g., because it was stored offline). This method makes use of the 'jabber:x:delay' namespace and has been documented variously in Internet-Drafts and elsewhere. Because this protocol is not required by &rfc2779;, the 'jabber:x:delay' namespace was removed from &xmppim;. This specification fills the void for canonical documentation.</p>
</section1>
<section1 topic='Protocol Definition' anchor='protocol'>
  <p>The 'jabber:x:delay' namespace is used to provide timestamp information about data stored for later delivery. The most common uses of this namespace are to stamp:</p>
  <ul>
    <li>A message that is sent to an offline entity and stored for later delivery.</li>
    <li>The last presence update sent by a connected node to a host.</li>
    <li>Messages cached by a multi-user chat room for delivery to new participants when they join the room.</li>
  </ul>
  <p>Information about the delivery delay is communicated by adding to the &lt;message/&gt; or &lt;presence/&gt; stanza one and only one &lt;x/&gt; child qualified by the 'jabber:x:delay' namespace. This information is added by the server or component that delivers the information. The following attributes are allowed on the &lt;x/&gt; element:</p>
  <ul>
    <li><cite>from</cite> -- The Jabber ID of the entity that originally sent the XML stanza or that delayed the delivery of the stanza (for example, the address of a multi-user chat room). This attribute is RECOMMENDED.</li>
    <li><cite>stamp</cite> -- The time when the XML stanza was originally sent. The format SHOULD be "CCYYMMDDThh:mm:ss" (see <link url="#time">A Note on Time Formats</link> below). This attribute is REQUIRED.</li>
  </ul>
  <p>In addition, the &lt;x/&gt; element MAY contain XML character data that provides a natural-language description of the reason for the delay.</p>
</section1>
<section1 topic='Examples' anchor='examples'>
  <example caption='Receiving a Message Sent While Offline'><![CDATA[
<message
    from='romeo@montague.net/orchard'
    to='juliet@capulet.com'
    type='chat'>
  <body>
    O blessed, blessed night! I am afeard.
    Being in night, all this is but a dream,
    Too flattering-sweet to be substantial.
  </body>
  <x xmlns='jabber:x:delay'
     from='capulet.com'
     stamp='20020910T23:08:25'>
    Offline Storage
  </x>
</message>
  ]]></example>
  <example caption='Receiving the Last Presence Update of Another Entity'><![CDATA[
<presence from='juliet@capulet.com/balcony' to='romeo@montague.net'>
  <status>anon!</status>
  <show>xa</show>
  <priority>1</priority>
  <x xmlns='jabber:x:delay'
     from='juliet@capulet.com/balcony'
     stamp='20020910T23:41:07'/>
</presence>
  ]]></example>
  <example caption='Receiving Cached Messages from a Conference Room'><![CDATA[
<message
    from='coven@macbeth.shakespeare.lit/secondwitch'
    to='macbeth@shakespeare.lit/laptop'
    type='groupchat'>
  <body>
    By the pricking of my thumbs,
    Something wicked this way comes.
    Open, locks,
    Whoever knocks!
  </body>
  <x xmlns='jabber:x:delay'
     from='coven@macbeth.shakespeare.lit'
     stamp='20020910T23:05:37'/>
</message>
  ]]></example>
</section1>
<section1 topic='A Note on Time Formats' anchor='time'>
  <p>&xep0082; defines the lexical representation of dates, times, and datetimes in Jabber protocols. Unfortunately, the 'jabber:x:delay' namespace predates that definition, and uses a datetime format ("CCYYMMDDThh:mm:ss") that is inconsistent with XEP-0082 and &w3xmlschema2;. Because a large base of deployed software uses the old format, this document specifies that applications using 'jabber:x:delay' SHOULD use the old format, not the format defined in XEP-0082. The timezone is be understood as UTC.</p>
</section1>
<section1 topic='Security Considerations' anchor='security'>
  <p>Data qualified by the 'jabber:x:delay' can expose information about the sender's presence on the network at some time in the past. However, this introduces no new vulnerabilities, since the same information would have been available in real time.</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>The 'jabber:x:delay' namespace is included in the protocol namespaces registry maintained by the &REGISTRAR;.</p>
</section1>
<section1 topic='XML Schema' anchor='schema'>
  <code><![CDATA[
<?xml version='1.0' encoding='UTF-8'?>

<xs:schema
    xmlns:xs='http://www.w3.org/2001/XMLSchema'
    targetNamespace='jabber:x:delay'
    xmlns='jabber:x:delay'
    elementFormDefault='qualified'>

  <xs:annotation>
    <xs:documentation>
      The protocol documented by this schema is defined in
      XEP-0091: http://www.xmpp.org/extensions/xep-0091.html
    </xs:documentation>
  </xs:annotation>

  <xs:element name='x'>
    <xs:complexType>
      <xs:simpleContent>
        <xs:extension base='xs:string'>
          <xs:attribute name='from' type='xs:string' use='optional'/>
          <xs:attribute name='stamp' type='xs:string' use='required'/>
        </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
  </xs:element>

</xs:schema>
  ]]></code>
</section1>
</xep>
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`<?xml version='1.0' encoding='UTF-8'?>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`<!DOCTYPE xep SYSTEM 'xep.dtd' [`
			`<!ENTITY % ents SYSTEM 'xep.ent'>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`%ents;`
			`]>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`<?xml-stylesheet type='text/xsl' href='xep.xsl'?>`
			`<xep>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`<header>`
			`<title>Delayed Delivery</title>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`<abstract>This specification provides canonical documentation of the jabber:x:delay namespace currently used within the Jabber community.</abstract>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`&LEGALNOTICE;`
			`<number>0091</number>`
			`<status>Active</status>`
			`<type>Historical</type>`
XSF/SIG cleanup git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@320 4b5297f7-1745-476d-ba37-a9c6900126ab 2007-01-14 22:38:19 -05:00			`<sig>Standards</sig>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`<approver>Council</approver>`
			`<dependencies>`
			`<spec>XMPP Core</spec>`
			`</dependencies>`
			`<supersedes/>`
			`<supersededby/>`
			`<shortname>x-delay</shortname>`
			`<schemaloc>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`<url>http://www.xmpp.org/schemas/x-delay.xsd</url>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`</schemaloc>`
			`&stpeter;`
			`<revision>`
			`<version>1.2</version>`
			`<date>2004-08-17</date>`
			`<initials>psa</initials>`
			`<remark>Specified that the timezone is to be understood as UTC; specified security considerations; corrected several small textual errors.</remark>`
			`</revision>`
			`<revision>`
			`<version>1.1</version>`
			`<date>2004-02-24</date>`
			`<initials>psa</initials>`
			`<remark>Corrected several small textual errors.</remark>`
			`</revision>`
			`<revision>`
			`<version>1.0</version>`
			`<date>2003-10-08</date>`
			`<initials>psa</initials>`
			`<remark>Per a vote of the Jabber Council, changed status to Active.</remark>`
			`</revision>`
			`<revision>`
			`<version>0.1</version>`
			`<date>2003-05-22</date>`
			`<initials>psa</initials>`
			`<remark>Initial version.</remark>`
			`</revision>`
			`</header>`
			`<section1 topic='Introduction' anchor='intro'>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`<p>The Jabber protocols have long included a method for indicating that a message or presence stanza was delayed in being delivered (e.g., because it was stored offline). This method makes use of the 'jabber:x:delay' namespace and has been documented variously in Internet-Drafts and elsewhere. Because this protocol is not required by &rfc2779;, the 'jabber:x:delay' namespace was removed from &xmppim;. This specification fills the void for canonical documentation.</p>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`</section1>`
			`<section1 topic='Protocol Definition' anchor='protocol'>`
			`<p>The 'jabber:x:delay' namespace is used to provide timestamp information about data stored for later delivery. The most common uses of this namespace are to stamp:</p>`
			`<ul>`
			`<li>A message that is sent to an offline entity and stored for later delivery.</li>`
			`<li>The last presence update sent by a connected node to a host.</li>`
			`<li>Messages cached by a multi-user chat room for delivery to new participants when they join the room.</li>`
			`</ul>`
			`<p>Information about the delivery delay is communicated by adding to the <message/> or <presence/> stanza one and only one <x/> child qualified by the 'jabber:x:delay' namespace. This information is added by the server or component that delivers the information. The following attributes are allowed on the <x/> element:</p>`
			`<ul>`
			`<li><cite>from</cite> -- The Jabber ID of the entity that originally sent the XML stanza or that delayed the delivery of the stanza (for example, the address of a multi-user chat room). This attribute is RECOMMENDED.</li>`
			`<li><cite>stamp</cite> -- The time when the XML stanza was originally sent. The format SHOULD be "CCYYMMDDThh:mm:ss" (see <link url="#time">A Note on Time Formats</link> below). This attribute is REQUIRED.</li>`
			`</ul>`
			`<p>In addition, the <x/> element MAY contain XML character data that provides a natural-language description of the reason for the delay.</p>`
			`</section1>`
			`<section1 topic='Examples' anchor='examples'>`
			`<example caption='Receiving a Message Sent While Offline'><![CDATA[`
			`<message`
			`from='romeo@montague.net/orchard'`
			`to='juliet@capulet.com'`
			`type='chat'>`
			`<body>`
			`O blessed, blessed night! I am afeard.`
			`Being in night, all this is but a dream,`
			`Too flattering-sweet to be substantial.`
			`</body>`
			`<x xmlns='jabber:x:delay'`
			`from='capulet.com'`
			`stamp='20020910T23:08:25'>`
			`Offline Storage`
			`</x>`
			`</message>`
			`]]></example>`
			`<example caption='Receiving the Last Presence Update of Another Entity'><![CDATA[`
			`<presence from='juliet@capulet.com/balcony' to='romeo@montague.net'>`
			`<status>anon!</status>`
			`<show>xa</show>`
			`<priority>1</priority>`
			`<x xmlns='jabber:x:delay'`
			`from='juliet@capulet.com/balcony'`
			`stamp='20020910T23:41:07'/>`
			`</presence>`
			`]]></example>`
			`<example caption='Receiving Cached Messages from a Conference Room'><![CDATA[`
			`<message`
			`from='coven@macbeth.shakespeare.lit/secondwitch'`
			`to='macbeth@shakespeare.lit/laptop'`
			`type='groupchat'>`
			`<body>`
			`By the pricking of my thumbs,`
			`Something wicked this way comes.`
			`Open, locks,`
			`Whoever knocks!`
			`</body>`
			`<x xmlns='jabber:x:delay'`
			`from='coven@macbeth.shakespeare.lit'`
			`stamp='20020910T23:05:37'/>`
			`</message>`
			`]]></example>`
			`</section1>`
			`<section1 topic='A Note on Time Formats' anchor='time'>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			<p>&xep0082; defines the lexical representation of dates, times, and datetimes in Jabber protocols. Unfortunately, the 'jabber:x:delay' namespace predates that definition, and uses a datetime format ("CCYYMMDDThh:mm:ss") that is inconsistent with XEP-0082 and &w3xmlschema2;. Because a large base of deployed software uses the old format, this document specifies that applications using 'jabber:x:delay' SHOULD use the old format, not the format defined in XEP-0082. The timezone is be understood as UTC.</p>
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`</section1>`
			`<section1 topic='Security Considerations' anchor='security'>`
			`<p>Data qualified by the 'jabber:x:delay' can expose information about the sender's presence on the network at some time in the past. However, this introduces no new vulnerabilities, since the same information would have been available in real time.</p>`
			`</section1>`
			`<section1 topic='IANA Considerations' anchor='iana'>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`<p>This document requires no interaction with &IANA;.</p>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`</section1>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`<section1 topic='XMPP Registrar Considerations' anchor='registrar'>`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`<p>The 'jabber:x:delay' namespace is included in the protocol namespaces registry maintained by the &REGISTRAR;.</p>`
			`</section1>`
			`<section1 topic='XML Schema' anchor='schema'>`
			`<code><![CDATA[`
			`<?xml version='1.0' encoding='UTF-8'?>`

			`<xs:schema`
			`xmlns:xs='http://www.w3.org/2001/XMLSchema'`
			`targetNamespace='jabber:x:delay'`
			`xmlns='jabber:x:delay'`
			`elementFormDefault='qualified'>`

			`<xs:annotation>`
			`<xs:documentation>`
			`The protocol documented by this schema is defined in`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`XEP-0091: http://www.xmpp.org/extensions/xep-0091.html`
Initial revision git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@2 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-02 18:22:13 -04:00			`</xs:documentation>`
			`</xs:annotation>`

			`<xs:element name='x'>`
			`<xs:complexType>`
			`<xs:simpleContent>`
			`<xs:extension base='xs:string'>`
			`<xs:attribute name='from' type='xs:string' use='optional'/>`
			`<xs:attribute name='stamp' type='xs:string' use='required'/>`
			`</xs:extension>`
			`</xs:simpleContent>`
			`</xs:complexType>`
			`</xs:element>`

			`</xs:schema>`
			`]]></code>`
			`</section1>`
JEP to XEP git-svn-id: file:///home/ksmith/gitmigration/svn/xmpp/trunk@38 4b5297f7-1745-476d-ba37-a9c6900126ab 2006-10-03 22:38:14 -04:00			`</xep>`