<remark><p>Initial published version.</p></remark>
</revision>
<revision>
<version>0.0.1</version>
<date>2007-07-03</date>
<initials>am</initials>
<remark><p>Initial version.</p></remark>
</revision>
</header>
<section1topic='Introduction'anchor='intro'>
<p>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. &xep0132; 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.</p>
<p>It was discussed whether this should be part of &xep0085;. 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.</p>
</section1>
<section1topic='Requirements'anchor='reqs'>
<p>The specification addresses remotely getting the user's attention in a more assertive way than simple text messages.</p>
</section1>
<section1topic='Protocol'anchor='protocol'>
<p>In the following conversation, a user talks to somebody, but this user doesn't respond. The second inquiry includes an attention extension.</p>
<examplecaption="User sends a regular message"><![CDATA[
<p>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 &NSNOTE;. Note: The message may or may not include a &BODY; element.</p>
<examplecaption="User tries to capture the other's attention"><![CDATA[
<body>I cannot. You know I cannot! Dr. Bogert and Dr. Lanning don't want me to.</body>
</message>
]]></example>
</section1>
<section1topic='Business Rules'anchor='rules'>
<p>The following rules apply to generating and processing of the attention extension.
<ol>
<li>Before sending an attention message stanza, the client MUST confirm support for it in the other client as described under <linkurl='#disco'>Determining Support</link>.</li>
<li>The message stanza containing the attention extension MAY contain a body and/or other extensions, which is to be displayed along with executing the attention event.</li>
<li>In message stanzas containing either &xep0203; data, attention extensions MUST be ignored, since this is an instant event which should not be replayed after a delay.</li>
<li>Messages containing an attention extension SHOULD use the headline message type to avoid offline storage.</li>
<li>Using the attention extension in &IQ; stanzas is not desirable, since this is part of the conversation.</li>
<p>If an entity supports receiving the attention extension, it MUST advertise that fact in its responses to &xep0030; information ("disco#info") requests by returning a feature of "http://www.xmpp.org/extensions/xep-0224.html#ns":</p>
<p>In addition, support for receiving attention extensions in message stanzas can be determined through the dynamic profile of Service Discovery defined in &xep0115;.</p>
<p>The implementation of the alert is up to the developer. Possible behavior is:</p>
<ul>
<li>Shaking the window.</li>
<li>Playing a specific sound not used for any other event.</li>
<li>Flashing the screen.</li>
<li>Enabling external hardware such as flashlights.</li>
<li>Let it be user customizable.</li>
</ul>
<p>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.</p>
<p>Rate-limiting might be desirable in some implementations.</p>
<p>Formal feedback in response to the attention request to the requesting user is not specified, and so the request might be silently dropped.</p>
<p>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.</p>
<p>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 ®ISTRAR; shall issue a permanent namespace in accordance with the process defined in Section 4 of &xep0053;.</p>