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 <[email protected]> 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:[email protected]] > *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 <[email protected]> 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. > > >
