[Standards] Last connection time of friend

Peter Waher Peter.Waher at clayster.com
Mon Mar 3 18:11:43 UTC 2014


Hello Ben

Thanks for your input. You're correct that you can always send the probe. What worries me is how many servers will actually route it. It only says servers SHOULD route the probe in RFC 6121.

How would you do this use case better, than by sending a probe?

Best regards,
Peter Waher


From: Ben Langfeld [mailto:ben at langfeld.me]
Sent: den 3 mars 2014 14:20
To: XMPP Standards
Subject: Re: [Standards] Last connection time of friend

The point here is that this is a normative recommendation against doing presence probes, because there's often a better way to achieve the result. It is not denying you the option of doing so.

On 3 March 2014 13:47, Peter Waher <Peter.Waher at clayster.com<mailto:Peter.Waher at clayster.com>> wrote:
Hello Dave

Thanks for the quick response. This looks like exactly what I need.

I'm a little worried about this statement in RFC 6121 though (and the explanation a little circular):

   Presence probes SHOULD NOT be sent by a client, because in general a
   client will not need to send them since the task of gathering
   presence from a user's contacts is managed by the user's server.
   However, if a user's client generates an outbound presence probe then
   the user's server SHOULD route the probe (if the contact is at
   another server) or process the probe (if the contact is at the same
   server) and MUST NOT use its receipt of the presence probe from a
   connected client as the sole cause for returning a stanza or stream
   error to the client.

Sending such probes seems to me to be a great way of finding connection problems in Internet of Things networks. Have to do some experiments to find out how it works out. Perhaps the explanation for why this should not be done by clients can be revised in the RFC?

Best regards,
Peter Waher

From: Dave Cridland [mailto:dave at cridland.net<mailto:dave at cridland.net>]
Sent: den 2 mars 2014 16:21
To: XMPP Standards

Subject: Re: [Standards] Last connection time of friend

Some servers also respond to a probe with the last offline presence (with a timestamp).

On 2 March 2014 19:17, Philipp Hancke <fippo at goodadvice.pages.de<mailto:fippo at goodadvice.pages.de>> wrote:
Am 02.03.2014 20:08, schrieb Peter Waher:

Is there a means to figure out the last time a friend connected to its XMPP server? Can you ask the server hosting the user account for last connection time? (You might not have been online to receive the presence message when the user went offline.)

http://xmpp.org/extensions/xep-0012.html#offline -- not sure how many servers implement it though.


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