[Standards] XEP-0073: Question about service discovery

Robin Redeker elmex at x-paste.de
Wed Feb 7 17:41:57 UTC 2007


On Wed, Feb 07, 2007 at 03:50:56PM +0100, Remko Tronçon wrote:
> >Then what are service discoveries (XEP-0030) and entity capabilities
> >(XEP-0115) for? I would assume that the other client does not support
> >anything beyond RFC3921 if it doesn't implement XEP-0115.
> 
> Service discovery was initially only done on specific occasions, and
> almost exclusively on request of the user. 
[.snip.]

Then this might needs some notice in XEP-0030. As I currently
read it there is nothing that says: "You should not send disco#info
requests to all contacts when logging in or a contact becomes available."

Same applies to XEP-0092. If jabber:iq:version-flooding of all contacts
is discuraged it should maybe contain a note about that. Or XEP-0092
should be deprecated and superseded by XEP-0115.
But for that, the information distributed by the mechanisms in XEP-0115
should propably also contain the operating system. I'm not sure whether
XEP-0115 already contains this information.

> 
> It became clear that you want have the information from disco#info
> available for all your contacts at all time (amongst others to make
> better UIs), but it is unreasonable to query each one of your contacts
> every time you or your contact logs on. This is why XEP-0115 is there:
> it describes a way to cache disco#info from  everybody, such that you
> have the information when you need it, and don't need to query it
> explicitly anymore when you need it.

Yes, XEP-0115 allows caching of some information. Thats indeed great!

But XEP-0030 disco#info requests are differnt from the ones in XEP-0115.

See XEP-0030:

   <iq type='get'
    from='romeo at montague.net/orchard'
    to='plays.shakespeare.lit'
    id='info1'>
        <query xmlns='http://jabber.org/protocol/disco#info'/>
   </iq>

But the requests in XEP-0115 are using only specific nodes, for example:

   <iq type='get' to='randomuser1 at capulet.com/resource'>
     <query xmlns='http://jabber.org/protocol/disco#info'
            node='http://exodus.jabberstudio.org/caps#0.9'/>
   </iq>

Is the information returned by the first one as the information returned by the
second one? I guess not. XEP-0115 does only allow caching of disco#info requests
to these nodes, but not of disco requests without a node attribute.

Are you sure that clients only want the information they can get via XEP-0115?
And not other information from a XEP-0030 disco#info request?


Robin



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