iCal to MQTT

This project fetches events from one or more iCal links (.ics) and publishes them to MQTT.

Configuration

Configuration is via environment variables:

• MQTT_CONNECTION_STRING - MQTT connection string, including protocol, host and port (default: mqtt://0.0.0.0:1883).
• MQTT_TOPIC_PREFIX - topix prefix (default: calendars).
• UPDATE_INTERVAL - interval in seconds for updates; if this is <= 0 then the program will run once and exit (default: 0).
• PUBLISH_HISTORIC_EVENTS - set to true to publish historic events, false to publish current and future events only (default: false).
• CALENDAR_URLS - semicolon-separated list of iCal URLs to fetch (if the URL happens to include a colon, replace it with %3B).

MQTT Topics

• ${prefix}/_meta/last_seen - RFC3339 timestamp of when the program last ran.
• ${prefix}/state/all_events - JSON array of all events (if enabled).
• ${prefix}/state/today_events - JSON array of events that include today.
• ${prefix}/state/today_and_future_events - JSON array of events that include today or are in the future.

Each event object takes the following form:

{
  "uid": "abcd1234", // event ID
  "start": "2023-03-14T00:00:00.000Z", // ISO timestamp
  "end": "2023-03-14T00:00:00.000Z", // ISO timestamp
  "wholeDays": true, // whether the event start/end includes a time component
  "summary": "Happy Pi Day!", // event title
  "description": "...", // event description (optional)
  "location": "...", // event location (optional)
  "calendar": "https://..." // calendar URL
}

For whole-day events the start time will usually be set to 00:00:00.000 on the first day of the event, and the end time will be set to 00:00:00.000 on the day after the last day of the event.