HDN is CLI tool for sending notification messages to D-Bus on a Linux desktop. It was originally built so I could use Home Assistant to send alerts to my desktop when certain events in my house change and it was named hass-dbus-notify. Since it can be used without Home Assistant it was renamed HDN. As a command line tool you can automate sending messages to D-Bus for almost anything.

Under the hood it uses Jeepeny which is a pure Python 3 implementation of the D-Bus protocol. It does all of the heavy lifting for HDN. Since HDN only requires Python 3, you do not need to install any system packages to interface with D-Bus. 🎉

pip install hdn

The first command of HDN is send. It can be used via the CLI to send messages to D-Bus. It also can read environment variables for it's configuration. This is the more fully featured command since it fully uses Typer's features to ensure the data for each option is correct.

Required options

• --summary TEXT Summary of the notification. [env var: HDN_SUMMARY] [required]
• --body TEXT Body of the notification. [env var: HDN_BODY] [required]

Optional options

• --urgency TEXT Urgency: low, normal, critical [env var: HDN_URGENCY] [default: normal]
• --object-path TEXT Object path [env var: HDN_OBJECT_PATH] [default: /org/freedesktop/Notifications]
• --bus-name TEXT Bus name [env var: HDN_BUS_NAME] [default: org.freedesktop.Notifications]
• --interface TEXT Interface [env var: HDN_INTERFACE] [default: org.freedesktop.Notifications]
• --message-bus TEXT Message bus: session, system [env var: HDN_MESSAGE_BUS] [default: session]
• --icon TEXT Message icon [env var: HDN_ICON] [default: dialog-warning]
• --expire INTEGER Message expiration (seconds) [env var: HDN_EXPIRE] [default: 3]
• --help Show the message and exit.

The second command of HDN is json. It can be used to read a JSON data from a file or stdin. It lightly uses Typer for the command but any options that are fed in via JSON are lightly sanity checked before being processed by HDN and sent to D-Bus. Expect weird things to happen if you send unexpected data in your values. At a minimum the required keys in your JSON need to be:

{
  "summary": "Minimal example summary",
  "body": "Minimal example body"
}

Here is a full example of a JSON payload that can be processed by HDN:

{
  "summary": "Full example summary",
  "body": "Full example body",
  "urgency": "critical",
  "object_path": "/org/freedesktop/Notifications",
  "bus_name": "org.freedesktop.Notifications",
  "interface": "org.freedesktop.Notifications",
  "message_bus": "session",
  "icon": "dialog-warning",
  "expire": 20
}

See the examples directory for more samples of JSON that are used in testing.

If you want to see what is going on with your messages you can use dbus-monitor to watch the bus in real time.

dbus-monitor interface=org.freedesktop.Notifications

• D-Bus Basic Design
• D-Bus Protocol
• freedesktop.org Icon Names

MIT License

Copyright (c) 2023 Joe Doss

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.