Sending desktop notification in Linux with Python with D-Bus directly

I recently found a lot of third-party libraries that help send desktop notifications in Linux. I just don’t get it. Most of these libraries just wrap the call to libnotify‘s notify-send into a function or even an over-engineered class. You don’t really need these third-party libraries to do the job… You can do the same job with merely two or three new lines in your code. notify-send is a command-line tool. You can call the command-line tool through Python’s subprocess:

import subprocess

subprocess.run(
    ["notify-send", "-u", "normal", "-t", "3000",
     "Hello world", "This is the notification body."],
    check=True)

Using `subprocess` to call `notify-send`

notify-send is a quick solution but requires libnotify and a call to an external executable. I don’t like it. Therefore, I always send the notification directly with D-Bus’ Python binding. Most desktop notification servers follow a standard called Desktop Notifications Specification. It exposes a D-Bus interface at org.freedesktop.Notifications and a method org.freedesktop.Notifications.Notify to send notifications from users’ applications. It’s OK if you don’t know anything about D-Bus. Just remember that you can send a desktop notification through D-Bus’ Python binding:

import dbus

item = "org.freedesktop.Notifications"

notfy_intf = dbus.Interface(
    dbus.SessionBus().get_object(item, "/"+item.replace(".", "/")), item)

notfy_intf.Notify(
    "", 0, "", "Hello world!", "This is the notification body.",
    [], {"urgency": 1}, 3000)

Sending a notification through D-Bus' Python binding

The D-Bus’ Python binding can be installed from PyPI:

$ pip install dbus-python

Installing D-Bus' Python binding

In notfy_intf.Notify, the fourth argument is the notification title, and the content body is at the fifth argument. Regarding the urgency, 0, 1, and 2 mean low, normal, and critical. The last argument indicates how long the notification box will be visible on the screen. The unit is milliseconds. So the 3000 here means 3 seconds. To understand the details of the arguments in the notfy_intf.Notify, refer to the documentation of org.freedesktop.Notifications.Notify.

You can now see that you don’t really need those third-party libraries to send simple desktop notifications.

4 Comments

Drugwash

Hi, this sounds fine when notifications are sent by the same user that is logged in but when trying to run this from a Python script running as root it won’t work because the root user doesn’t have access to another user’s DBus. So, how to solve this issue elegantly? Is there a way to patch root notifications through a dispatcher that would relay them to user’s desktop, or is there an easier, safer and more consistent way? i’m talking about wide compatibility with most common desktops out there: Xfce, GNOME, MATE, Cinnamon, KDE Plasma, Trinity etc.

March 26, 2023 Reply
Drugwash

Actually that’s not accurate. Having just tested the code in Mint 19.2 Cinnamon I noticed notifications are being delivered when run as root, but through a different daemon and/or settings than the regular user notification daemon. This is not elegant at all. It is also possible that a given system does not have any additional notification daemon installed and/or available.

So the question remains: how to connect to the regular daemon in order to send notifications that match the user settings?

March 26, 2023 Reply
Philstix

What are the other parameters used for in the notfy_intf.Notify() call?

I assume one is for an icon and another is for notification actions.

Any pointers to a reference that details the requirements to use those other parameters?

August 17, 2023 Reply
Jeremy Fleischman

Thanks for the writeup! It looks like the docs you linked to are gone. https://specifications.freedesktop.org/notification-spec/notification-spec-latest.html#command-notify appears to be working.

September 19, 2023 Reply

Sending desktop notification in Linux with Python with D-Bus directly

4 Comments

Leave a Reply Cancel reply