index.js

var Service, Characteristic;
const request = require('request');
const DEF_INTERVAL = 2000; //2s

const URL = "https://api.tzevaadom.co.il/notifications";
const HTTP_METHOD = "GET";
const HEADERS = {
    "Connection": "close",
    "X-Requested-With": "XMLHttpRequest",
    "Content-Type": "application/x-www-form-urlencoded; charset=UTF-8",
};

module.exports = function (homebridge) {
    Service = homebridge.hap.Service;
    Characteristic = homebridge.hap.Characteristic;
    homebridge.registerAccessory("homebridge-missiles-alert", "MissilesAlert", HttpMotion);
}

function HttpMotion(log, config) {
    this.log = log;
    this.lastNotificationId = null;

    // Error counters
    this.httpErrorResponseCount = 0;
    this.jsonParseErrorCount = 0;
    this.updateStateResponsePendingCount = 0;

    // url info
    this.url = URL;
    this.http_method = HTTP_METHOD;
    this.headers = HEADERS;
    this.name = config["name"];
    this.manufacturer = "Gal Mirkin";
    this.model = "MissilesAlerts";
    this.serial = "RVU729";
    this.update_interval = Number(config["update_interval"] || DEF_INTERVAL);
    this.cities = config["cities"] || ["all"];

    // Internal variables
    this.last_state = false;
    this.waiting_response = false;
}

HttpMotion.prototype = {
    updateState: function () {
        if (this.waiting_response) {
            this.updateStateResponsePendingCount++;
            if (this.updateStateResponsePendingCount >= 20) {
                this.updateStateResponsePendingCount = 0;
            }
            return;
        }
        this.updateStateResponsePendingCount = 0;
        this.waiting_response = true;

        var ops = {
            uri: this.url,
            method: this.http_method,
            headers: this.headers
        };

        request(ops, (error, res, body) => {
            var value = false;
            var recentAlerts = [];

            if (error) {
                this.httpErrorResponseCount++;
                if (this.httpErrorResponseCount >= 10) {
                    this.log('HTTP bad response (' + ops.uri + ') occurred 10 times in a row: ' + error.message);
                    this.httpErrorResponseCount = 0;  // reset the counter
                }
            } else if (!body) {
                error = true;
            } else {
                try {
                    var alerts = JSON.parse(body);

                    alerts.forEach(alert => {

                        // Check if the alert hasn't been processed before and contains the desired city
                        if (this.lastNotificationId !== alert.notificationId && 
                            (this.cities.includes("all") || alert.cities.some(city => this.cities.includes(city)))) { 
                            value = true;
                            this.lastNotificationId = alert.notificationId;
                            this.log("Your city is under attack! Get to the shelters right now!");
                        }
                    });

                    this.httpErrorResponseCount = 0;
                    this.jsonParseErrorCount = 0;
                } catch (parseErr) {
                    this.jsonParseErrorCount++;
                    if (this.jsonParseErrorCount >= 10) {
                        this.log('Error processing received information occurred 10 times in a row: ' + parseErr.message);
                        this.jsonParseErrorCount = 0;
                    }
                    error = parseErr;
                }
            }

            this.motionService
                .getCharacteristic(Characteristic.MotionDetected).updateValue(value, null, "updateState");
            this.last_state = value;
            this.waiting_response = false;
        });
    },

    getState: function (callback) {
        var state = this.last_state;
        if (!this.waiting_response && this.update_interval === 0) {
            this.log('Call to getState: last_state is "' + state + '", will update state now');
            setImmediate(this.updateState.bind(this));
        }
        callback(null, state);
    },

    getServices: function () {
        this.log("Cities are set to " + this.cities.join(", "));
        this.informationService = new Service.AccessoryInformation();
        this.informationService
            .setCharacteristic(Characteristic.Manufacturer, this.manufacturer)
            .setCharacteristic(Characteristic.Model, this.model)
            .setCharacteristic(Characteristic.SerialNumber, this.serial);

        this.motionService = new Service.MotionSensor(this.name);
        this.motionService
            .getCharacteristic(Characteristic.MotionDetected)
            .on('get', this.getState.bind(this));

        if (this.update_interval > 0) {
            this.timer = setInterval(this.updateState.bind(this), this.update_interval);
        }

        return [this.informationService, this.motionService];
    }
};