6mo ago

How do I troubleshoot dolphin's custom service menus?

Hi everyone! I recently created a custom service menu for the Dolphin file manager, but unfortunately, it doesn't seem to be working as expected.

My goal is to have a menu to convert image file formats quickly with image magick.

Here is the .desktop file I managed to arrange

 bash

    
[Desktop Entry]
Type=Service
Name=Convert Image
Icon=gtk-convert
MimeType=image/png;image/jpg;image/jpeg;image/ico;image/heic;image/svg;image/webp;
Actions=topng;tojpg;toico;towebp
X-KDE-Submenu=Convert Image

[Desktop Action topng]
Name=To Png
Exec=sh -c 'FILE="%f"; DIRECTORY="$(dirname $FILE)"; FILENAME="${FILE%.*}"; magick "$FILE" -format png "$DIRECTORY/$FILENAME.png"'

[Desktop Action tojpg]
Name=To Jpg
Exec=sh -c 'FILE="%f"; DIRECTORY="$(dirname $FILE)"; FILENAME="${FILE%.*}"; magick "$FILE" -format jpg "$DIRECTORY/$FILENAME.jpg"'

[Desktop Action toico]
Name=To Ico
Exec=sh -c 'FILE="%f"; DIRECTORY="$(dirname $FILE)"; FILENAME="${FILE%.*}"; magick "$FILE" -format ico "$DIRECTORY/$FILENAME.ico"'

[Desktop Action towebp]
Name=To Webp
Exec=sh -c 'FILE="%f"; DIRECTORY="$(dirname $FILE)"; FILENAME="${FILE%.*}"; magick "$FILE" -format webp "$DIRECTORY/$FILENAME.webp"'

When I right-click on an image my custom menu item appears as expected. However, when I click on the menu item, nothing happens. There are no error messages or any indication of what might be going wrong.

I made sure the .desktop file is executable and the sh script works when using it on the command line, so I'm out of ideas for what could be going wrong.

Are there any logs I can check to get more information about what's failing? I'm using plasma 6.3.3 on Arch btw

Edit: To answer how to troubleshoot custom service menus (specifically .desktops) the desktop-file-validate cli utlility checks all the syntax errors and can provide solutions to what's wrong. For my use case though, using a script file for the Exec line and avoiding any double quotes was the practical way of assuring my service menu works.

6 comments

You're using single quotes in your Exec lines, which is not legal .desktop file syntax.
I suggest replacing your single quotes with double quotes, and replacing your double quotes with backslash-escaped double quotes.
https://web.archive.org/web/20241130225327/https://specifications.freedesktop.org/desktop-entry-spec/latest/exec-variables.html
- If I understood correctly, I made the changes as you said like this:
  Exec=sh -c "FILE=\"%f\"; DIRECTORY=\"$(dirname \"$FILE\")\"; FILENAME=\"${FILE%.*}\"; magick \"$FILE\" -format png \"$DIRECTORY/$FILENAME.png\""
  Now when I click on the service menu option this error popup appears:
  Syntax error in command sh -c "FILE=f DIRECTORY=(dirname FILE FILENAME={FILE%.*} magick FILE\ -format png DIRECTORY/$FILENAME.png coming from
  It seems escaping the double quotes doesn't actually escape the backlash with it?
  I then tried escaping those new backlashes like this
  Exec=sh -c "FILE=\\"%f\\"; DIRECTORY=\\"$(dirname \\"$FILE\\")\\"; FILENAME=\\"${FILE%.*}\\"; magick \\"$FILE\\" -format png \\"$DIRECTORY/$FILENAME.png\\""
  and now Dolphin doesnt complain about syntax, but the new converted image doesn't get made :(
  
  I can't tell from that error message whether the inner quotes are being discarded when the command is run, or just hidden when the error message is displayed.
  Too bad it doesn't tell you what part of the command is causing the syntax error. Have you checked for more info in the output of journalctl --boot _UID=1000? (Assuming your user id is 1000 and you use systemd.)
  Re-reading the spec page that I linked above, I see reference to both a general escape rule and a quoting rule. That could be complicating things with the quotes and backslashes, and maybe even the dollar signs and semicolons, which apparently are reserved. In case it helps, I don't think those semicolons are needed at all.
  Before diving deeper into escaping rules, though, I would consider whether it's time to move the whole command line into a script, and simply pass %f to the script in your Exec= line. That would avoid the need for nested escaping/quoting, and allow you to write debug information to a temporary file when the script runs.

6 comments