failure-monitor.js

// Copyright 2021 Allterco Robotics EOOD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Shelly is a Trademark of Allterco Robotics

// Shelly Script example: Load monitoring and alerting in Shelly Gen2
//
// This script listens for events when power changes to 0 and if the switch is
// still on then it alerts that something might have happened to the load

let CONFIG = {
  notifyEndpoint: "http://push-notification-endpoint-url",
};

let notifications = [];

Shelly.addEventHandler(function (event, user_data) {
  if (typeof event.info.apower === "undefined") {
    return;
  }
  if (event.info.apower !== 0) {
    return;
  }
  Shelly.call(
    "switch.getstatus",
    { id: 0 },
    function (result, error_code, error_message, user_data) {
      if (result.output) {
        notifications.push("load might have failed");
      }
    },
    null
  );
}, null);

function _simple_encode(str) {
  let res = "";
  for (let i = 0; i < str.length; i++) {
    if (str.at(i) === 0x20) {
      res = res + "%20";
    } else {
      res = res + chr(str.at(i));
    }
  }
  return res;
}

Timer.set(1000, true, function () {
  if (notifications.length) {
    let message = notifications[0];
    notifications.splice(0, 1);
    print("ALERT: ", message);
    let nEndpoint = CONFIG.notifyEndpoint + _simple_encode(message);
    Shelly.call(
      "http.get",
      { url: nEndpoint },
      function (result, error_code, error_message) {
        print(JSON.stringify(result));
      },
      null
    );
  }
});