Guide: Calling D-Bus Methods

The application behind org.freedesktop.Notifications is responsible with desktop notifications (the small bubbles of text that appear at the top of the screen when some event happens). When an application wants to send a notification it needs to connect to D-Bus and call the Notify method from the org.freedesktop.Notifications interface.

In this example, we want to call the Notify method ourselves. To do this, we must first understand the signature of this method:

Notify (String arg_0, UInt32 arg_1, String arg_2, String arg_3, String arg_4, Array of [String] arg_5, Dict of {String, Variant} arg_6, Int32 arg_7) ↦ (UInt32 arg_8)

This doesn’t tell us much, but we can find more documentation here, since freedesktop is an open standard.

We’ll set the arguments to the following (for our simple case, most of them will be unused):

• app_name: ""

• replaces_id: 0

• app_icon: ""

• summary: "This is the title"

• body: "This is the content"

• actions: []

• hints: {}

• expire_timeout: -1

Now the question is how to actually call the method. Normally, we would have to write an application that connects to D-Bus and executes the call. But for demonstrative purposes there are easier ways.

One way is directly from d-feet. If we double-click on the Notify method in the right-side pane of d-feet, a window will open that allows us to call the method with any arguments that we want:

Then we click the Execute button and the notification will appear:

Another way is from the command-line. There’s the gdbus tool that can do this: