[JDEV] 0.7 Proposed Protocol Changes

[Jeremie]

Here are some changes I'd like to propose or bring up for discussion for
0.7.  Some are minor, and some major, but the essence of the changes are
to "tidy" up a bit and streamline things for understanding and
implementation of 0.7.


Minor:

=> (already discussed) Additional message "types" where type is mostly for
display: error, chat, groupchat.
=> Connections (client to server and server to server) are XML Streams
(see protocol section at http://docs.jabber.org/).


Major:

Rework "presence" model (renaming "status" to "presence").  See the
updated presence doc at http://docs.jabber.org/ in the protocol section.  
It doesn't break the old model, just builds on it in a slightly more
generic way.

Rename "nick" to "resource" and generalizing the use of resources.  Each
user can have multiple generic "resources" underneath them, a 3-tuple
system: server>user>resource.

--> Session resources: Each connection from a client becomes a session
resource, identical to the nickname setup in 0.6.

--> Remote resources: A user can tell a server to create a "remote"
resource.  The server would map/proxy this new resource to a remote
address and handle forwarding traffic to/from it.  For instance, there is
a pager transport and any user can create a "my pager" resource that maps
to uin1234 at pager.jabber.org.

Start utilizing Info/Query(IQ) as a fundamental part of the system. These
would replace the existing <login> and <roster> packets.

--> Query the server to authenticate: extensible for future uses, returns
receipt of success or failure. Example use of IQ to authenticate with the
server and create a session resource:
  <iq>
    <target>server</target>
    <type>auth</type>
    <set><user>jeremie</user><pass>foobar</pass><res>Jer</res></set>
  </iq>

--> Roster queries: Use IQ to fetch and manage the roster stored on the
server.  Example, client asking server for a group:
  <iq>
    <target>user</target>
    <type>roster</type>
    <query><group name="Work Buddies"/></query>
  </iq>
Response:
  <iq>
    <type>roster</type>
    <result>
      <group name="Work Buddies"><user name="Jon">jjames at isp.net</user></group>
    </result>
  </iq>


In the end, we have 3 consistent types of data everywhere in Jabber:
Messages, Presence, and Info/Query, all fundamentally extensible and have
clearly different purposes and modes of operation.

Much of this has been making it's way into the draft documentation at
docs.jabber.org.  Most of the docs are incomplete yet, but please take a
look at what's there and feed comments/suggestions back to
docs at jabber.org.

Jer