Gather.town smart object script. Set URL and SECRET.

gatherbot.sh

#!/bin/bash
KEY_HEX=$(printf %s "${SECRET#whsec_}" | base64 -d | od -An -tx1 | tr -d ' \n')

sign_and_send() {
  local BODY="$1"
  local WEBHOOK_ID=$(uuidgen)
  local TS=$(date +%s)
  local SIG=$(printf '%s' "${WEBHOOK_ID}.${TS}.${BODY}" \
    | openssl dgst -sha256 -mac hmac -macopt hexkey:"$KEY_HEX" -binary | base64)

  curl -sS -o - -w '\nHTTP %{http_code}\n' -X POST "$URL" \
    -H "content-type: application/json" \
    -H "webhook-id: $WEBHOOK_ID" \
    -H "webhook-timestamp: $TS" \
    -H "webhook-signature: v1,$SIG" \
    --data-raw "$BODY"
}

set_status() {
  local STATE="$1"
  case "$STATE" in
    off|on|question|alert|working) ;;
    *) echo "invalid state: '$STATE' (allowed: off on question alert working)" >&2; return 2 ;;
  esac
  sign_and_send "{\"type\":\"status.set\",\"timestamp\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\",\"data\":{\"state\":\"$STATE\"}}"
}

reset_status() {
  sign_and_send "{\"type\":\"status.reset\",\"timestamp\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\"}"
}

json_escape() {
  printf %s "$1" | sed -e 's/\\/\\\\/g' -e 's/"/\\"/g' -e 's/\t/\\t/g' | tr -d '\n\r'
}

activity_add() {
  local ID="$1" TEXT="$2" LINK="$3"
  if [ -z "$ID" ] || [ -z "$TEXT" ]; then
    echo "usage: $0 activity add <id> <text> [url]" >&2; return 2
  fi
  local DATA="{\"id\":\"$(json_escape "$ID")\",\"text\":\"$(json_escape "$TEXT")\""
  [ -n "$LINK" ] && DATA="$DATA,\"url\":\"$(json_escape "$LINK")\""
  DATA="$DATA}"
  sign_and_send "{\"type\":\"activity.add\",\"timestamp\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\",\"data\":$DATA}"
}

activity_remove() {
  local ID="$1"
  if [ -z "$ID" ]; then echo "usage: $0 activity remove <id>" >&2; return 2; fi
  sign_and_send "{\"type\":\"activity.remove\",\"timestamp\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\",\"data\":{\"id\":\"$(json_escape "$ID")\"}}"
}

activity_clear() {
  sign_and_send "{\"type\":\"activity.clear\",\"timestamp\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\"}"
}

usage() {
  cat >&2 <<USAGE
usage: $0 <command>
  ping                                  health check; prints preset + current state
  status <off|on|question|alert|working>
  reset                                 status back to off
  activity add <id> <text> [url]        add or update a feed entry by id
  activity remove <id>
  activity clear                        empty the feed
USAGE
}

case "${1:-ping}" in
  ping)   sign_and_send '{"type":"webhook.ping"}' ;;
  status) set_status "$2" ;;
  reset)  reset_status ;;
  activity)
    case "$2" in
      add)    activity_add "$3" "$4" "$5" ;;
      remove) activity_remove "$3" ;;
      clear)  activity_clear ;;
      *)      usage; exit 64 ;;
    esac
    ;;
  *) usage; exit 64 ;;
esac