Listening to incoming libnotify notifications using DBus

Question

I am attempting to filter every notification through espeak. However, I can't seem to find a way to get the notification body from a python script, or even what signal_name to listen to.

bus.add_signal_receiver(espeak,
                    dbus_interface="org.freedesktop.Notifications",
                    signal_name="??")

Trying to google for this only seems to yield results involving creating new notifications, so I am completely lost now.

Anyone can help me with this?

In short, what I want is to listen for incoming notifications using python, and obtaining the "body" attribute of the notification.

It seems a notification doesn't produce a signal i.e., `dbus-monitor "type='signal',interface='org.freedesktop.Notifications'"` shows nothing but `dbus-monitor "interface='org.freedesktop.Notifications'"` shows notifications (type is 'method_call' not 'signal'). — jfs, Sep 07 '12 at 21:34

score 15 · Answer 1 · answered Apr 20 '14 at 15:25

15

To keep this up to date: from dbus 1.5.something an extra parameter is required when adding a match string with bus.add_match_string_non_blocking to make sure we receive everything.

The resulting code would be the following:

import glib
import dbus
from dbus.mainloop.glib import DBusGMainLoop

def notifications(bus, message):
    print [arg for arg in message.get_args_list()]

DBusGMainLoop(set_as_default=True)

bus = dbus.SessionBus()
bus.add_match_string_non_blocking("eavesdrop=true, interface='org.freedesktop.Notifications', member='Notify'")
bus.add_message_filter(notifications)

mainloop = glib.MainLoop()
mainloop.run()

answered Apr 20 '14 at 15:25

joost

151
1
2

If I want to call another different dbus method inside notification filter, it doesn't work. All I get `unable to connect to session bus: Operation was cancelled`. We are passing `bus` to the filter. – Khurshid Alam Nov 16 '18 at 18:23
5

On my Python installation (Python 3, Ubuntu) I needed `from gi.repository import GLib as glib` to make this work. – Owen Jan 27 '20 at 03:04
1

Thanks for this! I ended up using this to do a (bad?) notification filter: https://gist.github.com/eacousineau/63651e498ddc31a7c1478f8638d0fd2e#file-scrub_notifications-py – eacousineau Nov 25 '20 at 22:17
Thanks, eacousineau! Your script works on Ubuntu 22.04 – Alek_A Jun 15 '22 at 10:21

score 7 · Answer 2 · answered Sep 20 '12 at 00:44

By notifications you mean the "OSD bubbles" that some software sends, like changing volume, IM chat, etc? You want to create a python program to capture those?

Well, Ask Ubuntu is not a programmer's QA, and software development is a bit beyond the scope, but here is a little code I did do capture notification bubbles:

import glib
import dbus
from dbus.mainloop.glib import DBusGMainLoop

def notifications(bus, message):
    if message.get_member() == "Notify":
        print [arg for arg in message.get_args_list()]

DBusGMainLoop(set_as_default=True)

bus = dbus.SessionBus()
bus.add_match_string_non_blocking("interface='org.freedesktop.Notifications'")
bus.add_message_filter(notifications)

mainloop = glib.MainLoop()
mainloop.run()

Leave this running in a terminal, then open another terminal window and test it:

notify-send --icon=/usr/share/pixmaps/debian-logo.png "My Title" "Some text body"

And the program will output this:

[dbus.String(u'notify-send'), dbus.UInt32(0L), dbus.String(u'/usr/share/pixmaps/debian-logo.png'), dbus.String(u'My Title'), dbus.String(u'Some text body'),...

As you may have guessed, message.get_args_list()[0] is the sender, [2] for icon, [3] for summary and [4] for body text.

For the meaning of the other fields, check the official specification docs

Looks like it no longer works as of sometime on or before 16.04. Joost's answer below does fix it. — Catskul, Jun 16 '16 at 15:37

score 3 · Answer 3 · answered Mar 24 '15 at 13:47

I had trouble getting any of the other examples to actually work but I got there in the end. Here's a working example:

import glib
import dbus
from dbus.mainloop.glib import DBusGMainLoop

def print_notification(bus, message):
  keys = ["app_name", "replaces_id", "app_icon", "summary",
          "body", "actions", "hints", "expire_timeout"]
  args = message.get_args_list()
  if len(args) == 8:
    notification = dict([(keys[i], args[i]) for i in range(8)])
    print notification["summary"], notification["body"]

loop = DBusGMainLoop(set_as_default=True)
session_bus = dbus.SessionBus()
session_bus.add_match_string("type='method_call',interface='org.freedesktop.Notifications',member='Notify',eavesdrop=true")
session_bus.add_message_filter(print_notification)

glib.MainLoop().run()

If you want to see a more detailed working example I recommend looking at Notifications.py in the recent_notifications project.

Magnotec · Answer 4 · 2022-07-04T18:19:10.023

The above example did not work at first, so I made some small changes and now it works perfectly.

import gi
from gi.repository import GLib
import dbus
from dbus.mainloop.glib import DBusGMainLoop

def print_notification(bus, message):
  keys = ["app_name", "replaces_id", "app_icon", "summary",
          "body", "actions", "hints", "expire_timeout"]
  args = message.get_args_list()
  if len(args) == 8:
    notification = dict([(keys[i], args[i]) for i in range(8)])
    print(notification["summary"], notification["body"])

loop = DBusGMainLoop(set_as_default=True)
session_bus = dbus.SessionBus()
session_bus.add_match_string("type='method_call',interface='org.freedesktop.Notifications',member='Notify',eavesdrop=true")
session_bus.add_message_filter(print_notification)

GLib.MainLoop().run()

Listening to incoming libnotify notifications using DBus

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