Setting environment variables for KDE's Plasma

I have been a Desktop linux user at the latest since 2005 (I signed up for the Gentoo Forums on 2005-01-26). Almost 19 years now. But you never stop to learn ;-)

I recently adepted that you you could get KDE's native file dialogs using Firefox (instead of those GTK abominations) by using xdg-desktop-portal, along with KDE's backend implementation xdg-desktop-portal-kde. The only thing to do is having those packages installed and setting the environment variable GTK_USE_PORTAL to 1.

So … how do we achieve this?! For a console, I would put export GTK_USE_PORTAL=1 to ~/.bashrc. This will work for an opened terminal I type firefox in. But the KDE desktop won't care about this. I had been bugged for KRunner not respecting my custom $PATH since ever … Plasma won't adopt this export as well.

What do we do? Mess with Firefox's .desktop file? That will be overwritten by the next update. Create a custom startup script that does something like GTK_USE_PORTAL=1 firefox? That sucks. No! We set the environment variable for Plasma!

That is surprisingly easy. One only has to find the correct docs about this. TL;DR: Every script inside ~/.config/plasma-workspace/env/ will be executed at Plasma's startup. Thus, we simply export our GTK_USE_PORTAL there. I now use the following script, which lives in ~/.config/plasma-workspace/env/exports.sh:

#!/bin/bash
export PATH="/home/tobias/bin:/home/tobias/.local/bin:$PATH"
export GTK_USE_PORTAL=1

This does not only make Firefox show native file dialogs, it also adds my custom $PATH to e.g. KRunner.

Now you know ;-)