🌉Bridge between MQTT and 🖥️Freedesktop.org Notify-Send desktop notifications (Ubuntu & other distros)🐧, to send notifications to your desktop over MQTT.

# Dependencies are: libnotify-bin, mosquitto-clients, jq, coreutils
sudo apt install libnotify-bin mosquitto-clients jq coreutils

# Download the script & set as executable (optional)
curl -O https://raw.githubusercontent.com/David-Lor/MQTT2NotifySend/master/mqtt2notifysend.sh
chmod u+x mqtt2notifysend.sh

# Run!
./mqtt2notifysend.sh -h localhost -t notifications

# Send a message to the broker from other terminal window
mosquitto_pub -h localhost -t notifications -m "{\"title\": \"Custom notification\", \"text\": \"Hello world\"}"

• Script arguments for MQTT connection are the same used with the mosquitto_sub command (run ./mqt2notifysend.sh --help to know more).
• The script expects a JSON string as payload, with the following tags:
  • title: notification title (optional)
  • text: notification body (required)
  • level: notification urgency level (optional; one of: low, normal, critical; default: normal)
  • iconB64: notification icon image, encoded as Base64 string (optional)

Certain settings can be tweaked using the following environment variables:

• RECONNECTION_DELAY: time to wait between connection attempts, in seconds (default: 5)
• DEFAULT_TITLE: default title for notifications sent without title (default: MQTT2NotifySend)
• DEFAULT_LEVEL: default notify-send level for notifications sent without level (default: normal)
• LOG_ENABLE: if true or 1, enable script logs (default: false)
• ICON_BASE_PATH: where the notification icon file is downloaded, for each notification. This is an absolute/relative path of the file, used as prefix (default: /tmp/mqtt2notifysend-icon)
• ICON_DELETE_DELAY: seconds to wait between the icon is decoded and deleted. Cannot be zero, as notifysend command may delay a bit and the icon may be removed when the notification pops up, not showing the icon (default: 5)

Usage:

LOG_ENABLE=true RECONNECTION_DELAY=1 DEFAULT_TITLE="Very important notification" DEFAULT_LEVEL=critical \
    bash mqtt2notifysend.sh -h localhost -t notifications

• 0.3.0 - Support sending icon for notifications, as base64-encoded string
• 0.2.1 - Allow to disable logs; logs disabled by default; amends on script syntax; describe environment variables on README
• 0.2.0 - Initial new Bash version from scratch
• v0.1.0 - (Deprecated) Initial new version from scratch (branch python/develop)
• v0.1 - (Deprecated) Initial version (branch python/master)

• Support non-JSON payloads (only text and title-text split by delimiter)
• Identify when mosquitto_sub fails due to connection error or user input (args) error
• Validate dependencies installed before connecting
• Support icons sent by URL