Re: Detect screen-lock in shell/c++

[Bastien Nocera <hadess hadess net>]

On Mon, 2014-11-03 at 10:03 +0100, Mathieu Slabbinck wrote:
> 2014-11-03 9:32 GMT+01:00 Bastien Nocera <hadess hadess net>:
>         On Mon, 2014-11-03 at 08:43 +0100, Mathieu Slabbinck wrote:
>         > I have a cross-platform application that runs on Ubuntu
>         14.04 (Unity &
>         > GNome) & Fedora (GNome). There I need to determine if the
>         screensaver
>         > is active or not and if the screen is locked or not.
>         >
>         > I found out that I can get the screensaver info with:
>         > gnome-screensaver-command -q
>         
>         As far as I know, neither Unity nor gnome-shell use
>         gnome-screensaver
>         anymore. In fact, gnome-screensaver has been closed for new
>         bugs.
>
>
> Didn't know that's deprecated. Works fine still.

It's not "deprecated", it's obsolete. It won't do anything with GNOME or
recent versions of Unity.

>  Any idea on the correct current handling to get tis information?
>
>
>         > But I cannot seem to figure out how I can detect a screen
>         lock. For
>         > example on Unity I can use:
>         >
>         > gdbus call -e -d com.canonical.Unity
>         -o /com/canonical/Unity/Session -m
>         com.canonical.Unity.Session.IsLocked
>         >
>         > but that's a Unity-specific item. So what's the best
>         approach to get
>         > screen lock in GNome?
>         
>         What do you actually want to do? Why do you need to detect the
>         screen
>         saver? Or do you need to detect that the screen is locked?
>
> Well the application I created should do action A when the user logs
> out or locks the screen, and the application should do action B when
> the screen saver comes up.
> Simple as that. 

You can use the GNOME and Unity specific interfaces, or you can use
logind's session API to get the status. On my system, for example, going
in and out of the screensaver, you can see the IdleHint changing:
$ gdbus monitor  --system --dest org.freedesktop.login1 --object-path /org/freedesktop/login1/session/_31
Monitoring signals on object /org/freedesktop/login1/session/_31 owned by org.freedesktop.login1
The name org.freedesktop.login1 is owned by :1.1
/org/freedesktop/login1/session/_31: org.freedesktop.DBus.Properties.PropertiesChanged 
('org.freedesktop.login1.Session', {'IdleHint': <true>, 'IdleSinceHint': <uint64 1415006348876052>, 
'IdleSinceHintMonotonic': <uint64 516705962866>}, @as [])
/org/freedesktop/login1/session/_31: org.freedesktop.login1.Session.Unlock ()
/org/freedesktop/login1/session/_31: org.freedesktop.DBus.Properties.PropertiesChanged 
('org.freedesktop.login1.Session', {'IdleHint': <false>, 'IdleSinceHint': <uint64 1415006353519410>, 
'IdleSinceHintMonotonic': <uint64 516710606224>}, @as [])