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copied!<p>@poke asked for a little more regarding my comment.</p> <p>The first way that people tend to do device identification is to encode the device name into the resource portion of the JIDs used by that device, such as <code>joe@example.com/MYCLIENT</code> or <code>joe@example.com/MYCLIENT_[random string]</code>, then do string matching on the resource. This will appear to work for a while, until you need to write another client for a different device, at which point, you've probably encoded both <em>identity</em> of the client as well as the <em>features</em> of that client into the resource string, and stuff starts to get tough.</p> <p>A much better solution is to use <a href="http://xmpp.org/extensions/xep-0115.html" rel="nofollow">XEP-0115</a>. Read the How-it-works section <strong>very</strong> carefully. It is a confusing idea to most people the first time they read it. Summary:</p> <pre><code><presence from='romeo@montague.lit/orchard'> <c xmlns='http://jabber.org/protocol/caps' hash='sha-1' node='http://code.google.com/p/exodus' ver='QgayPKawpkPSDYmwT/WM94uAlu0='/> </presence> </code></pre> <p>When a contact sends presence, she adds a capabilities tag, which includes a node name, which is just a URI you make up that describes your client. That URI can be used to select an icon, or there's another approach we'll get to.</p> <p>Next, you ask the sender what that icky ver string means:</p> <pre><code><iq from='juliet@capulet.lit/chamber' id='disco1' to='romeo@montague.lit/orchard' type='get'> <query xmlns='http://jabber.org/protocol/disco#info' node='http://code.google.com/p/exodus#QgayPKawpkPSDYmwT/WM94uAlu0='/> </iq> </code></pre> <p>And then you <strong>CACHE</strong> the result:</p> <pre><code><iq from='romeo@montague.lit/orchard' id='disco1' to='juliet@capulet.lit/chamber' type='result'> <query xmlns='http://jabber.org/protocol/disco#info' node='http://code.google.com/p/exodus#QgayPKawpkPSDYmwT/WM94uAlu0='> <identity category='client' name='Exodus 0.9.1' type='pc'/> <feature var='http://jabber.org/protocol/caps'/> <feature var='http://jabber.org/protocol/disco#info'/> <feature var='http://jabber.org/protocol/disco#items'/> <feature var='http://jabber.org/protocol/muc'/> </query> </iq> </code></pre> <p>After doing some normalization, you can SHA1-hash that result, and ensure that the hash matches the icky ver string. Now, anyone who gives you that hash, you know their capabilities. If you need to specify non-standard capabilities, just make up your own URIs to describe them, and add a feature to your caps.</p> <p>Finally, if you don't want to run around modifying all of your clients when you add a new client to your mix, you can include an extension in your caps that just specifies a URL for the client icon. <a href="http://xmpp.org/extensions/xep-0232.html" rel="nofollow">XEP-0232</a> (which is deferred, but that can't stop you from using it if you want, and can be resurrected if someone got excited about it) suggests:</p> <pre><code><iq from='juliet@capulet.lit/chamber' to='romeo@montague.lit/orchard' id='disco1' type='result'> <query xmlns='http://jabber.org/protocol/disco#info' node='http://code.google.com/p/exodus#RnWHG/MCjSwxZCk+p2kuN7i9kzo='> <x xmlns='jabber:x:data' type='result'> <field var='FORM_TYPE' type='hidden'> <value>urn:xmpp:dataforms:softwareinfo</value> </field> <field var='icon'> <media xmlns='urn:xmpp:media-element' height='80' width='290'> <uri type='image/jpeg'>http://www.shakespeare.lit/clients/exodus.jpg</uri> <uri type='image/jpeg'>cid:sha1+f24030b8d91d233bac14777be5ab531ca3b9f102@bob.xmpp.org</uri> </media> </field> </x> </query> </iq> </code></pre>

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