Plasma Task Manager Notifications

Taskbar badge notifications for KDE Plasma 6. Dynamically discovers running applications via KWin, monitors desktop notifications via D-Bus, and sets badge counts on taskbar icons using the Unity Launcher API.

How it works

1. Discovers apps dynamically by querying KWin via D-Bus — enumerates open windows using WindowsRunner.Match, then calls KWin.getWindowInfo for each to get the desktopFile property. Rediscovers every 30 seconds in a background thread.
2. Runs an unfiltered dbus-monitor --session subprocess (unfiltered is required to capture method return messages which contain the assigned notification ID).
3. Parses the dbus-monitor output as a stream, tracking three message types:
   • method_call with member=Notify — extract the app_name and message serial
   • method_return with matching reply_serial — extract the notification ID
   • signal with member=NotificationClosed — notification was dismissed
4. Matches app_name (case-insensitive) against the dynamically discovered app map. Also supports Flatpak apps via desktop-entry hints.
5. Emits com.canonical.Unity.LauncherEntry.Update signals via gdbus emit to set/clear badge counts and the urgent flag on the corresponding taskbar icon.
6. Uses a small KWin script to clear an app's badge when one of its windows is opened or activated.
7. On shutdown (SIGINT/SIGTERM), clears all badges.

Requirements

• KDE Plasma 6 with KWin and Task Manager
• dbus-monitor (from dbus-tools, typically pre-installed)
• gdbus (from glib2, typically pre-installed)
• Rust toolchain (to build)

Install

git clone https://git.nmm.ee/asko/plasma-task-manager-notifications.git
cd plasma-task-manager-notifications
make install

This installs the binary to ~/.local/bin/ and the systemd service to ~/.config/systemd/user/.

Enable at login

systemctl --user enable --now plasma-task-manager-notifications.service

Check status

systemctl --user status plasma-task-manager-notifications.service
journalctl --user -u plasma-task-manager-notifications.service -f

Uninstall

make uninstall

Usage

Run manually (logs to stderr):

plasma-task-manager-notifications

Test with a sample notification:

notify-send --app-name=firefox "Test" "Badge should appear"

Development

cargo test        # run all tests
cargo build       # debug build
make build        # release build

Architecture

The crate is split into four modules:

Module	Purpose
parser	Streaming parser for dbus-monitor text output
app_map	Tracks discovered apps, pending notifications, and active badge counts
discovery	Queries KWin D-Bus interfaces to discover running apps and their desktop file IDs
badge	Emits Unity LauncherEntry Update signals via gdbus
activation	Monitors KWin window activation and clears the corresponding app badge

All modules are designed for testability — external D-Bus calls are injected as function parameters in tests.

Known limitations

• Processes all session bus traffic (unfiltered monitor). Lightweight in practice but could theoretically be optimized with BecomeMonitor D-Bus API.
• Only badges apps that currently have an open window. Pinned taskbar icons without a running instance won't be badged.
• If two apps share the same last dot-segment in their desktop file ID, they would collide in the match map. Unlikely in practice.
• Firefox web app notifications all badge under the single Firefox icon.
• Notifications that expire via timeout also emit NotificationClosed, so badges clear when notifications auto-dismiss.

License

MIT