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

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"use strict";
import mqtt from 'async-mqtt';
class TTNAppServer {
get connection_string() {
return `${this.settings.ttn.tls ? "mqtts" : "mqtt"}://${this.settings.ttn.host}:${this.settings.ttn.port}/`
}
// Destructure the awilix container
constructor({ settings, ansi, MessageHandler, log }) {
this.settings = settings;
/** @type {Ansi} */
this.a = ansi;
/** @type {Log} */
this.log = log;
/** @type {MessageHandler} */
this.message_handler = MessageHandler;
}
async run() {
// 1: Sanity checks
if(this.settings.ttn.app_id == "CHANGE_THIS" || this.settings.ttn.access_key == "CHANGE_THIS") {
this.log.error(`Error: No TTN app id 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;
}
if(this.settings.ttn.devices.includes("CHANGE_THIS")) {
this.log.error(`Error: No device names 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;
}
// 2: Connect
this.ttn_client = await this.connect();
this.ttn_client.on("message", this.handle_message.bind(this));
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this.log.log(`[mqtt] Connected to ${this.connection_string}`);
// 3: Subscribe
let result = await this.ttn_client.subscribe(this.settings.ttn.devices.map(
(device_name) => `${this.settings.ttn.app_id}/devices/${device_name}/up`
));
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this.log.log(`[mqtt] Subscribed to ${result.map((el) => el.topic).join(", ")}`);
}
connect() {
return new Promise((resolve, _reject) => {
let client = mqtt.connect(this.connection_string, {
username: this.settings.ttn.app_id,
password: this.settings.ttn.access_key
});
client.once("connect", () => resolve(client));
});
}
async handle_message(topic, message_buffer) {
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let message = message_buffer.toString("utf8"),
message_object = null;
try {
message_object = JSON.parse(message);
} catch(error) {
this.log.log(error);
return false;
}
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this.log.log(`[mqtt/handler] Got message from ${topic}`);
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await this.message_handler.handle(message_object);
}
}
export default TTNAppServer;