LoRaWAN-Signal-Mapping/server/ttn-app-server/MessageHandler.mjs

"use strict";

import { decode_payload } from './DecodePayload.mjs';
import { get_id_number } from '../Helpers/IdGenerator.mjs';

class MessageHandler {
	get debug() {
		return this.settings.logging.verbose;
	}
	constructor({ settings, ReadingRepo, GatewayRepo }) {
		this.settings = settings;
		this.repo_reading = ReadingRepo;
		this.repo_gateway = GatewayRepo;
	}
	
	async handle(message) {
		if(this.debug) console.log(message);
		
		if(this.settings.ttn.encryption_key == "CHANGE_THIS") {
			this.log.error(`Error: No encryption key specified. Try filling in the required values in settings.toml. If they don't exist yet, try using server/settings.default.toml as a reference.`);
			return false;
		}
		
		let decoded_payload = decode_payload(message.payload_raw, this.settings.ttn.encryption_key);
		if(this.debug) console.log(decoded_payload);
		
		let rssis = [];
		for(let gw of message.metadata.gateways) {
			if(this.debug) console.log("gateway ", gw);
			// Insert the gateway info into the database if it doesn't exist already
			if(!this.repo_gateway.exists(gw.gtw_id)) {
				this.repo_gateway.add({
					id: gw.gtw_id,
					latitude: gw.latitude, longitude: gw.longitude,
					altitude: gw.altitude
				});
			}
			
			// Generate an RSSI object
			rssis.push({
				id: await get_id_number(),
				gateway_id: gw.gtw_id,
				rssi: gw.rssi,
				snr: gw.snr,
				channel: gw.channel
			});
		}
		
		// Add the reading and the associated RSSIs to the database
		this.repo_reading.add({
			id: decoded_payload.id,
			latitude: decoded_payload.latitude,
			longitude: decoded_payload.longitude,
			
			data_rate: message.metadata.data_rate,
			code_rate: message.metadata.coding_rate,
			
			rssis
		});
	}
}

export default MessageHandler;