NODE: Easily send Push Notifications through PushBullet

send_notification.js

// Important to use dotenv (https://www.npmjs.com/package/dotenv) for security reasons
// every saved env variable is available inside "process.env"
require("dotenv").config();
var redis = require("redis");
var pushBullet = require("pushbullet");
require("moment");
var exec = require('child_process').exec;
var promise = require('promise');
// Localized Date
var moment = require('moment-timezone');
var momentTimezone = "America/Caracas";
var todayDate = moment().tz(momentTimezone).format("YYYY-MM-DD");
// Config Redis
var redisClient = redis.createClient({
    host: process.env.REDIS_HOST,
});
// Config PushBullet
var pusher = new pushBullet(process.env.PUSHBULLET_KEY);
var deviceParams = {"channel_tag" : process.env.PUSHBULLET_CHANNEL_TAG};
// Message components
var activeUsers = "";
var serverStatus = "";

// Wrap a redis query in a promise
var getActiveUsers = function() {
  return new promise(function (resolve, reject) {
    // The redis query is async
    redisClient.smembers("active:users", function (err, replies) {
      if (err) {
        activeUsers = 0;
        resolve();
        return;
      }
      activeUsers = replies.length
      redisClient.quit();
      resolve();
    });
  });
}

// Wrap a command call in a promise
var getServerStatus = function () {
  return new promise(function (resolve, reject) {
    serverStatus = "Status unknown!";
    // With "exec" the command call return either "stdout" or "stderr"
    exec("/sbin/status --system user-", function (stdout, stderr) {
      // In any case we store the response
      serverStatus = (stdout || '') + (stderr || '')
        // Some message formatting
        .trim()
        .replace("driver-socket ", "")
        .replace("start/running, ", "OK")
        .replace("process ", "@");
      resolve();
    });
  })
};

var sendNotification = function () {
  var pushMoment = moment()
    .tz(momentTimezone)
    .format("D/MMM hh:mma");
  noteBody.push("[" + serverStatus + "]");
  noteBody.push(activeUsers + " active users");
  var noteContent = noteBody.join("\n");
  pusher.note(deviceParams, pushMoment, noteContent);
};

// Promises party <3
getActiveUsers()
  .then(getServerStatus)
  .done(sendNotification);