Re: org.freedesktop.NetworkManager.Settings.PropertiesChanged deprecated

[Andrei Borzenkov <arvidjaar gmail com>]

On 14.07.2021 19:30, mh mike franken de wrote:
> Hi,
>
> On Mittwoch, 14. Juli 2021 16:52:15 CEST Thomas Haller wrote:
> [...]
> > > so how can I use org.freedesktop.DBus.Properties.PropertiesChanged
> > > then?
> > > What would be the correct way instead?
> > > Using
> > >   my $busobjpath = "/org/freedesktop/NetworkManager/Settings";
> > > as before?
> > > This doesn't work either, though.
> > >
> > > Probably there is a fundamental misunderstanding regaring the concept
> > > on my
> > > side.
> >
> > Hi,
> >
> > I am not familiar with this Perl's Net::DBus, but in general:
> >
> >
> > On D-Bus, you have the well-known name
> > ("org.freedesktop.NetworkManager") where you find NetworkManager's D-
> > Bus API.
> >
> >
> > There, you find many D-Bus objects, at paths that start with
> > "/org/freedesktop/NetworkManager". You see them with `busctl tree
> > org.freedesktop.NetworkManager`.
> >
> > All of these objects also implement the standard D-Bus interface
> > "org.freedesktop.DBus.Properties" -- as documented at
> > https://dbus.freedesktop.org/doc/dbus-specification.html
> > That interface, has (among) others a signal "PropertiesChanged".
> >
> >
> > This "org.freedesktop.DBus.Properties.PropertiesChanged" signal works
> > very similar to the earlier "PropertiesChanged" signals from the NM
> > specific interfaces ( "org.freedesktop.NetworkManager*").
> >
> > So, yes, there should be not much to do except replace the interface
> > name "org.freedesktop.NetworkManager*" with
> > "org.freedesktop.DBus.Properties".
> >
> >
> > you mention specifically
> >
> >   my $busobjpath = "/org/freedesktop/NetworkManager/Settings";
> >
> > In `d-feet` you'll see that this object only has three properties. So
> > you'll see few PropertiesChanged signals on that object...
>
> Yeah, my fault, I meant
> my $busobjpath = "/org/freedesktop/NetworkManager";
>
> 8-(
>
> > Does that help? Otherwise, please share a working, minimal example.
>
> Ok.
> This is the working example I used before - btw. it stems from a suggestion 
> you made back in 2016/2017 :)
>
> #!/usr/bin/perl -w
>
> use strict;
>
> use Data::Dumper;
> $Data::Dumper::Sortkeys = 1;
> $Data::Dumper::Indent = 1;
> use Net::DBus;
> use Net::DBus::Dumper;
> use Net::DBus::Reactor;
>
> my $oBUS = Net::DBus->system || die $!;
> my $nm = "org.freedesktop.NetworkManager";
> my $oNM = $oBUS->get_service( $nm ) || die $!;
> my $nmobjpath = "/org/freedesktop/NetworkManager";
> my $nmif = "org.freedesktop.NetworkManager";
> my $oNMIF = $oNM->get_object( $nmobjpath, $nmif ) || die $!;
>
> $nmobjpath = "/org/freedesktop/NetworkManager/Settings";
> $nmif = "org.freedesktop.NetworkManager.Settings";
> my $oNMIFS = $oNM->get_object( $nmobjpath, $nmif ) || die $!;
>
> $oNMIF->connect_to_signal(
>   "PropertiesChanged", sub {
>     &{ \&dbnm_onNMPropertiesChanged }( $oNM, $oNMIF, $oNMIFS, @_ );
>   }
> );
> my $reactor = Net::DBus::Reactor->main() || die $!;
> $reactor->run() || die $!;
>
> sub dbnm_onNMPropertiesChanged {
>   my( $oNM, $oNMIF, $oNMIFS, $props ) = @_;
>   print "\n- props -\n", Dumper( $props ), "\n--\n";
> }


NM PropertiesChanged and D-Bus
org.freedesktop.DBus.Properties.PropertiesChanged have different
signatures. You are dumping interface name, not properties dictionary.