[SR-Users] Terminate dialog from another dialog

[Joel Serrano]

Hi Henning,

On Tue, Mar 27, 2018 at 12:50 PM, Henning Westerholt <hw at kamailio.org> wrote:
>
> Am Montag, 26. März 2018, 01:57:31 CEST schrieb Joel Serrano:
> > I'm trying to set kamailio to not allow simultaneous calls from the same
> > user, but if a second call comes in, the behavior desired is to process
> > that second call and terminate the previous (already active) one.
> >
> > Say you have call A that creates dialog A.
> >
> > Then you have call B come in, creates dialog B.
> >
> > Can I save some info from dialog (call) A in a htable for example, then
> > check that htable for the needed info from dialog (call) B and terminate
> > dialog (call) A if it exists?
> >
> > I think using dlg_get() and dlg_bye() would do the trick but not 100% sure
> > how they work..
> >
> >
> > The example in the docs seems exactly the case:
> >
> > dlg_get --> "Search and set current dialog based on Call-ID, From-Tag and
> > To-Tag parameters"
> >
> > if(dlg_get("abcdef", "123", "456"))
> > {
> > dlg_bye("all");
> > }
> >
> > After the dlg_get() and dlg_bye() what happens to call B? Does the route
> > continue running or does it end? Will it automatically switch back to the
> > current dialog or do you have to manually switch back running dlg_get()
> > again? (Sorry if I'm not explaining myself correctly, let me know if it
> > sounds confusing)
>
> Hello Joel,
>
> you coult track the number of current dialogs per user with the dialog
> profiles function.
>
> Have a look to the set_dlg_profile and get_profile_size function in the
> module. Its also explained generally in the top of the module docs. You could
> store the dialog information for the termination also in a htable, as you
> already mentioned. Then call dlg_bye() for the first call.

Problem is I need to allow current call, and hangup earlier one. This
is because of the design, the users are joining conferences really,
not placing calls, so it makes more sense like this:

- User-A joins conference-A from device-A
- User-A joins conference-B from device-B
- Kamailio must allow User-A on conf-B and terminate dialog of User-A on conf-A.

>
> If you would reverse your logic, like not allowing the second call setup if
> there is already one call, it would be much easier only with the two dialog
> functions mentioned above.
>
> Best regards,
>
> Henning

I ended up using the RPC command dlg.end_dlg instead of the
dlg.terminate_dlg as I can add an extra param "custom headers" which
is useful.

In case anyone else is curious (NOTE: Read my Update and Update2
emails in this thread to better understand where this piece of code
comes from):

event_route[dialog:start] {

...
        if ($sht(bcalls=>$fU::callid) != $null) {
                jsonrpc_exec('{"jsonrpc": "2.0","method":
"dlg.end_dlg","params": [$sht(bcalls=>$fU::h_entry),
$sht(bcalls=>$fU::h_id), "X-Reason: MAX_ACTIVE_CHANNELS\r\n"],"id":
1}');
                if ($jsonrpl(code)==200) {
                        xlog("L_INFO", "User check: previous active
call terminated, current call added to cache - M=$rm R=$ru ID=$ci\n");
                } else {
                        xlog("L_INFO", "User check: couldn't terminate
previous call, updated cache with current call - M=$rm R=$ru
ID=$ci\n");
                }
        } else {
                xlog("L_INFO", "User check: Call OK, added to cache -
M=$rm R=$ru ID=$ci\n");
        }
        $sht(bcalls=>$fU::h_id) = $dlg(h_id);
        $sht(bcalls=>$fU::h_entry) = $dlg(h_entry);
        $sht(bcalls=>$fU::callid) = $dlg(callid);
...

}


The part I still don't like is the jsonrpc_exec(), but I don't know
other ways of doing it, and I don't know really if there is a
performance hit doing it like this rather than using some function,
for now, it's working ;)


Cheers,
Joel.