Add Telegram notification script

Requires:
- API Token for a bot created with the Telegram Bot Father.
- A Chat ID for a user/group that the bot has permission to post to.

notify/telegram.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+
+#Support Telegram Bots
+
+#TELEGRAM_BOT_APITOKEN=""
+#TELEGRAM_BOT_CHATID=""
+
+telegram_send() {
+  _subject="$1"
+  _content="$2"
+  _statusCode="$3" #0: success, 1: error 2($RENEW_SKIP): skipped
+  _debug "_statusCode" "$_statusCode"
+
+  TELEGRAM_BOT_APITOKEN="${TELEGRAM_BOT_APITOKEN:-$(_readaccountconf_mutable TELEGRAM_BOT_APITOKEN)}"
+  if [ -z "$TELEGRAM_BOT_APITOKEN" ]; then
+    TELEGRAM_BOT_APITOKEN=""
+    _err "You didn't specify a Telegram BOT API Token TELEGRAM_BOT_APITOKEN yet."
+    return 1
+  fi
+  _saveaccountconf_mutable TELEGRAM_BOT_APITOKEN "$TELEGRAM_BOT_APITOKEN"
+
+  TELEGRAM_BOT_CHATID="${TELEGRAM_BOT_CHATID:-$(_readaccountconf_mutable TELEGRAM_BOT_CHATID)}"
+  if [ -z "$TELEGRAM_BOT_CHATID" ]; then
+    TELEGRAM_BOT_CHATID=""
+    _err "You didn't specify a Telegram Chat id TELEGRAM_BOT_CHATID yet."
+    return 1
+  fi
+  _saveaccountconf_mutable TELEGRAM_BOT_CHATID "$TELEGRAM_BOT_CHATID"
+
+  _content="$(printf "*%s*\n%s" "$_subject" "$_content" | _json_encode)"
+  _data="{\"text\": \"$_content\", "
+  _data="$_data\"chat_id\": \"$TELEGRAM_BOT_CHATID\", "
+  _data="$_data\"parse_mode\": \"markdown\", "
+  _data="$_data\"disable_web_page_preview\": \"1\"}"
+
+  export _H1="Content-Type: application/json"
+  _telegram_bot_url="https://api.telegram.org/bot${TELEGRAM_BOT_APITOKEN}/sendMessage"
+  if _post "$_data" "$_telegram_bot_url"; then
+    # shellcheck disable=SC2154
+    _message=$(printf "%s\n" "$response" | sed -ne 's/.*"ok":\([^,]*\).*/\1/p')
+    if [ "$_message" = "true" ]; then
+      _info "telegram send success."
+      return 0
+    fi
+  fi
+  _err "telegram send error."
+  _err "$response"
+  return 1
+}