Subject Re: Disconnected User
Author Michael Vilhelmsen
--- In, Stefan Heymann <lists@...> wrote:

Ah ... I See.
Quite nice.


I just told my boss.

I think that he'll wait until FB 2.1 (eventhough its quite some time).
But should he change his mind, I know what to do.


> >> It would be quite easy to make, though ... hmmm ...
> > Hm - Sorry ....
> > quite easy to make ...
> > I can't see how.
> > Give me a hint ...
> The application could send UDP packets (low bandwith usage, simple to
> implement) to the Licencing Server, let's say every minute. A client
> that didn't send these for, say, 2 minutes is considered to be offline
> and is not counted any more.
> A continuous TCP connection would waste resources and have the same
> problem as the TCP connection that is used for Firebird: The server
> doesn't get notified when the connection breaks ungracefully.
> So TCP could be used to get permission to connect or gracefully
> disconnect. And UDP could be used for saying "Hi, I'm still there".
> To make it perfect, one could implement a UDF that connects to the
> Licencing Service and checks if the Firebird connection still has a
> valid Licencing connection. If not, it could do all kind of weird
> things ...
> Just a few thoughts.
> > Whatever I think of has to do with polling the connected users.
> Polling the clients would mean you'd have to implement a listener in
> the client. It would probably be easier to tell clients to "push"
> these "I'm still there" messages to the server. When the client
> doesn't get a response back from the server it must shut down work or
> try to get a new licenced connection.
> Best Regards
> Stefan