Skip notify-send job if screen locked?

Question

I have a cron which runs a script every hour, it uses a notify-send for a notification on the Ubuntu 18.04 desktop (Gnome) once it starts.

What can I add to the script to:

If screen is locked then exit.
If screen is not locked then continue as normal with notification.

The answer below lead me to depending on environment:

$ qdbus org.freedesktop.ScreenSaver /ScreenSaver org.freedesktop.ScreenSaver.GetActive

$ qdbus org.kde.screensaver /ScreenSaver org.freedesktop.ScreenSaver.GetActive

$ qdbus org.gnome.ScreenSaver /ScreenSaver org.gnome.ScreenSaver.GetActive

Possible duplicate of unity - how to detect if the screen is locked? — WinEunuuchs2Unix, Dec 31 '18 at 01:07
18.04 uses Unity when upgrading from 16.04 and Unity can be added to any 18.04 installation but, I understand your point. — WinEunuuchs2Unix, Dec 31 '18 at 04:28
@WinEunuuchs2Unix and you missed where I explicitly stated "Ubuntu 18.04 desktop (Gnome)". :) — PrincessOfPower, Dec 31 '18 at 07:37
I should know better than to argue with a Princess :P. I've retracted my close vote and posted an answer to know which Desktop Screen Saver is active. — WinEunuuchs2Unix, Dec 31 '18 at 13:55

score 5 · Accepted Answer · answered Dec 31 '18 at 00:43

There is a setting to hide notifications while the lock screen is enabled:

You can also modify this setting via the command line:

gsettings set org.gnome.desktop.notifications show-in-lock-screen false

But, since you asked, you can also use gdbus on the command line with the --session parameter and org.gnome.ScreenSaver to determine if the screen is locked.

score 0 · Answer 2 · edited Jun 12 '20 at 14:37

Test if screen saver is active

qdbus will tell you if the screen saver (used by Lock Screen) is active. First you need to know which environment you are using: Gnome, Unity, KDE, etc.

In this example, Unity is active whilst Gnome and KDE are not:

$ qdbus org.freedesktop.ScreenSaver /ScreenSaver org.freedesktop.ScreenSaver.GetActive
false
$ qdbus org.gnome.ScreenSaver /ScreenSaver org.gnome.ScreenSaver.GetActive
Error: org.freedesktop.DBus.Error.UnknownMethod
No such interface 'org.gnome.ScreenSaver' on object at path /ScreenSaver
$ qdbus org.kde.screensaver /ScreenSaver org.freedesktop.ScreenSaver.GetActive
Service 'org.kde.screensaver' does not exist.

For the Gnome desktop the second option will return false and an error message will appear for the first and third options.

Skip notify-send job if screen locked?

2 Answers2

Test if screen saver is active