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From Thomas Kratz <eisw...@googlemail.com>
Subject Re: [vysper] Sending unavailable on lost connection
Date Wed, 03 Mar 2010 13:54:33 GMT
Thanks for the help so far.

I started to dive into the code. So far I guess I need A
PresenceHandler and I need to get him to process a mock presence
Stanza. What I don't see by now is how I can to that. Can anyone point
me to a place in the code that would make me understand how to do this
?

Regards
Thomas

2010/2/27 Bernd Fondermann <bf_jak@brainlounge.de>:
> Hi Thomas,
>
> Thomas Kratz wrote:
>> Hi,
>>
>> I am quite new and I hope I send this to the right list.
>
> It is. Welcome.
> Noticed your blog post today. Thanks for mentioning Vysper. :-)
> Though, to be fair there is at least one more Apache-licensed XMPP
> server out there, doubly licensened GPL and ASL, AFAIR - don't remember
> the name from the top of my head right now.
>
>> I just
>> started off with vysper and I found that I don't get notofied when the
>> connection gets lost (for example when I force eclispe to shut down my
>> process, I still see the user as available.
>>
>> I dived into the code and found some todo's in AbstractSessionContext:
>>
>>  public void endSession() {
>>       // thats one of my first ideas
>>       LatestPresenceCache presenceCache
>> =getServerRuntimeContext().getPresenceCache();
>>       PresenceStanza stanza = presenceCache.remove(initiatingEntity);
>>
>>         StanzaWriter stanzaWriter = getResponseWriter();
>>         stanzaWriter.close();
>>         sessionStateHolder.setState(SessionState.CLOSED); // no more
>> traffic going through
>>         getServerRuntimeContext().getResourceRegistry().unbindSession(this);
>>         // TODO send unavailable to all contacts and other resources
>>         // TODO remove latest availability from LatestPresenceCache
>>         // TODO close underlying transport (TCP socket)
>>     }
>>
>> I dont have to exact knowledge of the protocol, but could you give me
>> a hint if this is ok so far and how I can get the roster of the entity
>> to send them unavailable Stanzas ?
>
> First, I think you're looking at the right piece of code.
>
> I don't think it's that easy.
>
> endSession() gets called in different situations. One of them is after
> sending out a stream error. According to the spec, you MUST not send any
> more stanzas after that to the client(!), so no unavail stanza in that
> direction, we have to make sure of that (have a test). Contacts might
> receive the unavailable regardless of this.
>
> However, when the client abruptly goes away, there should be graceful
> notifications. This is already handeled by
> PresenceAvailabilityHandler.handleOutboundUnavailable(). Maybe it would
> be feasible to go that path (by somehow mocking an unavailable stanza).
>
> Additionally, we should check if when the server goes down we can still
> send out those unavailables. Maybe we can't.
>
> If the server closes the connection unilaterally, it should send
> </stream:stream> to the client. This must be taken care of.
>
> The relevant section of the XMPP spec is here
>
> http://xmpp.org/internet-drafts/draft-ietf-xmpp-3920bis-04.html#streams-close
>
>> Any help would be appreciated.
>
> Do you think you can come up with a patch for any of those?
>
>  Bernd
>



-- 
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http://thomaskratz.blogspot.com

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