[Standards] Inconsistent Subscriptions in XMPP

Pavel Simerda pavlix at pavlix.net
Wed Feb 25 14:55:06 UTC 2009


You just have to tell the deveopers to do it, then :).

On Tue, 24 Feb 2009 15:54:38 +0000
Pedro Melo <melo at simplicidade.org> wrote:

> Hi,
> 
> On Feb 24, 2009, at 12:49 AM, Pavel Simerda wrote:
> 
> > There are several cases when subscription databases in XMPP are
> > inconsistent.
> >
> > You may view subscription information as a global distributed  
> > database.
> > Subscription state between two JIDs, for example a at A and b at B are  
> > stored
> > in two places at the same time. Servers A and B maintain their own
> > copies of subscription state.
> 
> [....]
> 
> > What with the roster items that are inconsistent?
> >
> > * Mark as inconsistent, let the client present it to the user to
> > take action.
> >
> > * Auto-repair and thus maintain consistency
> >
> > Looking forward to all feedback.
> 
> When you send out a <presence type="probe" /> include the local
> "view" of the subscription state.
> 
> The receiving server can then look to see if the state is consisten  
> with his own state. If you opt by the lowest trust level (a from/to  
> beats a both, none beats all), you should be able to re-sync  
> subscription state automagically.
> 
> Best regards,


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