How to convert KDE plasmoid's `metadata.desktop` to `metadata.json` using `desktoptojson`?

Question

I'm writing my first KDE plasmoid using QML. The hello world example uses a metadata.desktop file, while this KDE Plasmoid tutorial talks about a metadata.json instead and says that the metadata.desktop is 'discouraged' now and a desktop file should be converted to json using desktoptojson.

However, when I browse the globally installed plasmoids under /usr/share/plasma/plasmoids/ they all have both the metadata.desktop and metadata.json.

First question: So, what is really recommended? Just the metadata.json? Or both?

And, I wasn't able to find the desktoptojson tool. I'm using Linux Mint and the ./kdesrc-build --initial-setup for debian based systems says that it's "This is woefully incomplete and not very useful" ... I read that "most users of this [i.e. desktoptojson] utility will use the CMake macro kservice_desktop_to_json as part of the process of building a plugin.". However, I haven't found the documentation yet how to use this.

Second question: In case one should maintain both files (for whatever reason), should I use desktoptojson to keep them in sync? And if yes, how?

Thanks!

Answer 1

Here is how to convert metadata.desktop to metadata.json - inside the directory where the metadata.desktop file is:

$ desktoptojson -s plasma-applet.desktop -i metadata.desktop

Remove metadata.desktop file:

$ rm metadata.desktop

And just in case - to install plasmoid:

$ kpackagetool5 -i Plasmoid-name

To remove plasmoid:

$ kpackagetool5 -r Plasmoid-name

(Usually just copy-paste to /home/user/.local/share/plasma/plasmoids does the same trick as install - remove).

Answer 2

First question: So, what is really recommended? Just the metadata.json? Or both?

In the current source code, most stock KDE applets such as the task manager use metadata.json's and have dropped the metadata.desktop's. It may be that the desktop files you have locally are left over from old versions, the new format was installed but the old one was never deleted.

Second question: In case one should maintain both files (for whatever reason), should I use desktoptojson to keep them in sync? And if yes, how?

The man page on Arch you linked to has all the information. The tool is part of the package kservice. Find the equivalent in the repository for your distribution. Then, to use it

1. as part of a CMake macro:

add_library(myplugin MODULE ${myplugin_SRCS})
kservice_desktop_to_json(myplugin myplugin.desktop)

2. directly on the command-line:

desktoptojson -i myplugin.desktop -o myplugin.json