Le Tue, 14 Oct 2008 10:33:20 -0600, Peter Saint-Andre <[EMAIL PROTECTED]> a écrit :
> Alban Crequy wrote: > > Hi, > > > > To start a link-local conversation with XEP-0174 between two > > clients, any of the 2 clients can initiate the stream. If the 2 > > contacts start to chat at the same time, we may have 2 streams > > initiated in both directions. It seems this case does not happen > > often because users usually don't start to chat precisely at the > > same time. > > > > You suggested that having several streams between 2 clients was not > > a problem: > > > > Le Thu, 14 Aug 2008 10:51:06 -0600, > > Peter Saint-Andre <[EMAIL PROTECTED]> a écrit : > >> Alban Crequy wrote: > >>> If we want the XEP to say there can be only one stream between two > >>> clients, we should define the correct behaviour when two clients > >>> initiate a TCP connection to each other at the same time. Do we > >>> want one connection to win and the second to be closed? > >> I don't think we need to restrict clients to one stream at a time. > > > > However, if the 2 clients both implement XEP-030 Service Discovery > > and XEP-0115 Entity Capabilities, they will both initiate a stream > > in order to send a discovery request as soon as they appear online > > via DNS-SD, without user intervention. > > Really? I thought we were advertising caps in DNS TXT. See the "ver" > record here: > > http://xmpp.org/extensions/xep-0174.html#registrar-linklocal-reg Indeed, we know the "ver" record without opening a stream. But the "ver" record is not enough to know all the caps. > So I think that opening a stream to everyone who appears online via > DNS-SD is a bad idea. > > Thus I would say that if you know the "ver", you'll know what the > other entity is. But if you don't know the "ver", don't automatically > open a stream to the other entity just to do all the caps lookup > magic via disco. I need to know all the contact capabilities in Telepathy, even if there is no open stream. If an application want to display a contact chooser to start a VNC session, a game, or whatever on top of XMPP, I need to know which contacts are able to do VNC or a specific game. I implemented an automatic caps lookup via disco in telepathy-salut (the XEP-0174 implementation in the Telepathy framework). It opens a stream only if a "ver" TXT record is advertised *and* if the "ver" record is not already known. -- Alban
