By chance, I found that there is a folder called tools within the Darktable Git repository. In there, among other interesting scripts, I found a script called “watch_folder.sh”. This script makes use of DBus to send a Lua import command to Darktable. Bingo! Exactly what I needed.
The only downside I found with this approach is, that Darktable needs to be running for that to work. Anyways, it appears to be the closest I can get to have command-line-based image import in Darktable.
DBus was new to me but it turned out that the basics aren’t that hard to understand.
Now the only thing left to do was to take the idea from this “watch_folders.sh” script and implement it within my mediatool.
With that out of the way now, there is no technical issue left. Fingers crossed. The tool itself still needs some polishing though. Nevertheless, I’m really happy that I got it working today.