How to read RTDB randomly generated node and it's value? - node.js

Question

Below is my typescript code and its already connected to telegram and managed to sent a message.
Currently I'm trying to tinker with it even more by reading the randomly generated node Arduino and MQ7 created and sending it as a message on telegram.
import * as functions from "firebase-functions";
import * as express from "express";
import * as cors from "cors";
import * as admin from "firebase-admin";
admin.initializeApp();
const bot = express();
bot.use(cors( {origin: true}));
bot.post("/", async function(req, res) {
const telegramText = req.body;
req.body.message &&
req.body.message.chat &&
req.body.message.chat.id &&
req.body.message.from &&
req.body.message.from.first_name;
if (telegramText) {
const chat_id = req.body.message.chat.id;
const first_name = req.body.message.from.first_name;
const receivedMessage = req.body.message.text;
// Define your RTDB Reference
const rtdbReference = admin.database().ref("Sensor MQ7");
const mq7ref = rtdbReference.child("-NHi7dBPMlVi6hXrnI03");
const valref = mq7ref.child("MQ7");
// Fetch the data
const snap = await valref.get();
const snapValue = snap.val();
// Inject snapvalue in the response
return res.status(200).send({
method: "sendMessage",
chat_id,
text: `${first_name}\n${receivedMessage}\n${snapValue}`,
});
}
return res.status(200).send({status: "An error occured"});
});
export const router = functions.https.onRequest(bot);
The typescript code works I figured out how to read entries from the database and write it into telegram as well as learning a little bit about the reference and functions. Right now I'm trying to figure out how to output the value whenever a new node is created. The new node are randomly generated # Arduino and mq7 gas sensor. Basically whenever the sensor picks up dangerous amount of carbon monoxide, it'll send the input to firebase, and a new node is created with a new value. I've classified the Parent = Sensor MQ7, Middle child = "randomly generated node", Last child = MQ7. Any help, advice, or recommendation is greatly appreciated. Please explain like I'm 5 because I just started doing all of it this week and I'm really really new to cloud functions. Thank you!
RTDB

Answer 1

The typescript code (for sending to Telegram) works and right now I'm
trying to figure out how to read entries from the database and write
it into telegram
In a Cloud Function you need to use the Node.js Admin SDK to interact with the Firebase services.
Here is how to read the data at a specific Reference in the Realtime Database:
import * as functions from "firebase-functions";
import * as express from "express";
import * as cors from "cors";
import * as admin from 'firebase-admin'; <== NEW
admin.initializeApp(); <== NEW
const bot = express();
bot.use(cors( {origin: true}));
bot.post("/", async function(req, res) {
const telegramText = req.body;
req.body.message &&
req.body.message.chat &&
req.body.message.chat.id &&
req.body.message.from &&
req.body.message.from.first_name;
if (telegramText) {
const chat_id = req.body.message.chat.id;
const first_name = req.body.message.from.first_name;
const receivedMessage = req.body.message.text;
//Define your RTDB Reference
const rtdbReference = admin.admin.database().ref('foo/bar');
// Fetch the date
const snap = await rtdbReference.get();
const snapValue = snap.val();
// Do whatever you need with snapValue to inject it in your response...
return res.status(200).send({
method: "sendMessage",
chat_id,
text: `Hello ${first_name}, \n You sent us message: ${receivedMessage}`,
});
}
return res.status(200).send({status: "An error occured"});
});
export const router = functions.https.onRequest(bot);