I am working on a small piece of our Volity project, and I see several
ways to do it. They'll all work, but I'm not sure which is most in tune
with the zen of Jabber.
What I want to do is send a game invitation as part of a <message>. (Could
be either IM or group-chat.) This is a set of fields; if one of our Volity
clients receives it, the invitation will be displayed with appropriate UI
("Do you want to join this game? [] yes [] no" and so on.) If a generic
client receives the message, it should ignore the invitation part and
display it as a standard message.
So option 1 would be to define some new protocol, maybe with a JEP (if any
other clients want to handle the invitation info), and stick the fields
directly into a custom element:
<message to="..." from="..." type="normal">
<body>Play a game!</body>
<invitation xmlns="http://volity.org/protocol/invite";>
<table>...</table>
<referee>...</referee>
</invitation>
</message>
(There are more fields than that; I'm simplifying here.)
This is fine, except that we may add or redefine fields as we expand our
goals. And I don't want to change the XML schema every time that happens.
Okay, Jabber has a way to handle that, which is data forms. So, option 2:
<message to="..." from="..." type="normal">
<body>Play a game!</body>
<invitation xmlns="http://volity.org/protocol/invite";>
<x xmlns="jabber:x:data" type="result">
<field var="table"><value>...</value></field>
<field var="referee"><value>...</value></field>
</x>
</invitation>
</message>
But then I notice JEP-0068, and I think maybe I can do this without any
custom protocol at all. Option 3:
<message to="..." from="..." type="normal">
<body>Play a game!</body>
<x xmlns="jabber:x:data" type="result">
<field var="FORM_TYPE" type="hidden">
<value>http://volity.org/protocol/form/invite</value>
</field>
<field var="table"><value>...</value></field>
<field var="referee"><value>...</value></field>
</x>
</message>
So our client watches for a result form of the appropriate FORM_TYPE, and
other clients ignore the extraneous (to them) form.
Which of these is most friendly to the Jabber system? We've gotten this
far by using existing JEPs, so I have a slight preference to *not*
introduce new Jabber protocol. But I'm more interested in figuring out
what will work right with existing and future Jabber software.
--Z
--
"And Aholibamah bare Jeush, and Jaalam, and Korah: these were the borogoves..."
*
Making a saint out of Reagan is sad. Making an idol out of Nixon ("If the
President does it then it's legal") is contemptible.
