udp-json.js

'use strict';

const dgram = require('dgram');

let Service, Characteristic;

module.exports = (homebridge) => {
  Service = homebridge.hap.Service;
  Characteristic = homebridge.hap.Characteristic;

  homebridge.registerAccessory('homebridge-udp-json', 'UDPJSON', UDPJSONPlugin);
};

class UDPJSONPlugin
{
  constructor(log, config) {
    this.log = log;
    this.name = config.name;
    this.name_temperature = config.name_temperature || this.name;
    this.name_humidity = config.name_humidity || this.name;
    this.listen_port = config.listen_port || 8268;

    this.informationService = new Service.AccessoryInformation();

    this.informationService
      .setCharacteristic(Characteristic.Manufacturer, "Bosch")
      .setCharacteristic(Characteristic.Model, "RPI-UDPJSON")
      .setCharacteristic(Characteristic.SerialNumber, this.device);

    this.temperatureService = new Service.TemperatureSensor(this.name_temperature);

    this.temperatureService
      .getCharacteristic(Characteristic.CurrentTemperature)
      .setProps({
        minValue: -100,
        maxValue: 100
      });

    this.humidityService = new Service.HumiditySensor(this.name_humidity);

    this.server = dgram.createSocket('udp4');
    
    this.server.on('error', (err) => {
      console.log(`udp server error:\n${err.stack}`);
      this.server.close();
    });

    this.server.on('message', (msg, rinfo) => {
      console.log(`server received udp: ${msg} from ${rinfo.address}`);

      let json;
      try {
          json = JSON.parse(msg);
      } catch (e) {
          console.log(`failed to decode JSON: ${e}`);
          return;
      }

      const temperature_c = json.temperature_c;
      //const pressure_hPa = json.pressure_hPa; // TODO
      //const altitude_m = json.altitude_m;
      const humidity_percent = json.humidity_percent;
 
      this.temperatureService
        .getCharacteristic(Characteristic.CurrentTemperature)
        .setValue(temperature_c);

      this.humidityService
        .getCharacteristic(Characteristic.CurrentRelativeHumidity)
        .setValue(humidity_percent);
    });

    this.server.bind(this.listen_port);

  }

  getServices() {
    return [this.informationService, this.temperatureService, this.humidityService]
  }
}