Build & Install

A small D-Bus listener that watches for org.freedesktop.Notifications.Notify calls, filters by app name + sender, and appends matches to a plain-text log file in a human-readable [timestamp] Sender: body format. Runs as a persistent systemd user service so it survives logouts/reboots.

1. Dependencies

Debian/Ubuntu:

sudo apt install build-essential pkg-config libdbus-1-dev

Fedora:

sudo dnf install gcc pkgconf-pkg-config dbus-devel

Arch:

sudo pacman -S base-devel dbus

2. Build

make

Or manually:

gcc -O2 -Wall -Wextra -o build/notify_logger logger.c $(pkg-config --cflags --libs dbus-1)

Test it manually first (Ctrl+C to stop):

./notify_logger --app whatsapp-linux-app --sender Name --out ./matches.log

Send yourself a test notification, or wait for a real one, and confirm a line appears in matches.log and on stdout, e.g.:

[2026-07-08 14:32:10] Name : hey, are you around?

If nothing shows up, see Troubleshooting below (eavesdrop policy).

3. Install as a persistent user service (systemd)

make install
mkdir -p ~/notify_logger ~/.config/systemd/user
cp logger.service ~/.config/systemd/user/notify-logger.service

systemctl --user daemon-reload
systemctl --user enable --now notify-logger.service

This makes it:

• Start automatically on login (WantedBy=default.target)
• Restart automatically if it crashes (Restart=on-failure)
• Log matches to ~/notify_logger/matches.log

Check status / logs:

systemctl --user status notify-logger.service
journalctl --user -u notify-logger.service -f

To change the target app/sender/output path, edit the ExecStart= line in ~/.config/systemd/user/notify-logger.service, then:

systemctl --user daemon-reload
systemctl --user restart notify-logger.service

Optional: survive reboot even when not logged in

By default, user systemd units only run once you're logged in (or after a graphical session starts, per After=graphical-session.target in the unit). If you want it running even before login (e.g. on headless boot), enable lingering:

loginctl enable-linger $USER

4. Uninstall

systemctl --user disable --now notify-logger.service
rm ~/.config/systemd/user/notify-logger.service
rm ~/.local/bin/notify_logger
systemctl --user daemon-reload

Troubleshooting

No matches ever appear, even for real notifications: Modern dbus-broker/dbus-daemon policies often block a non-owning process from eavesdropping on someone else's method calls unless explicitly allowed. This build already requests eavesdrop='true' in the match rule, which works on most default session-bus configs. If it still doesn't work, check:

dbus-monitor "interface='org.freedesktop.Notifications'"

If dbus-monitor also sees nothing, your session bus config is restricting eavesdropping — check /usr/share/dbus-1/session.conf and any drop-ins under /etc/dbus-1/session.d/ for <policy> rules limiting eavesdrop.

summary doesn't match the sender name you expect: Not all apps put the contact name in summary. If matching by summary alone is unreliable for your WhatsApp client build, run dbus-monitor while receiving a message from the target contact and inspect the actual argument order/values — some clients put the sender in body prefix text instead, or expose a more stable identifier in the hints dict (6th positional arg), which this program currently doesn't parse.