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Firebase Realtime database showing strange behavior

I am using react-native-firebase in an ejected expo app and trying to build a presence detection system in my chat app which will detect that if the message recipient is online and if not when was he/she was last online. The data will be stored as follows in firebase realtime database:
{
lastSeen:[{
[userId]:{
state: boolean
time: serverTimeStamp
}
}]
}
The problem is that firebase console never shows the data and only if recipient is online then app shows this data (even though its not visible in console) but if user is offline then nothing is returned and no error generated. I have set read and write to true in realtimeDB rules. Here is the code I am using:
import database from "#react-native-firebase/database";
export const updateUserLastSeen = (userId) => {
const userStatusDatabaseRef = database().ref("/lastSeen/" + userId);
console.log("updatelast", userId);
userStatusDatabaseRef
.set({
state: true,
time: database.ServerValue.TIMESTAMP,
})
.then(() => console.log("online"))
.catch((e) => console.log(e));
// database()
// .ref(".info/connected")
// .on("value", function (snapshot) {
// if (snapshot.val() == false) {
// return;
// }
userStatusDatabaseRef
.onDisconnect()
.set({
state: false,
time: database.ServerValue.TIMESTAMP,
})
.then(function () {
console.log("disconnect configured");
// userStatusDatabaseRef.set({
// state: true,
// time: database.ServerValue.TIMESTAMP,
// });
});
// });
};
export const checkUserLastSeen = (userId, setUserLastSeen) => {
console.log("check last", userId);
database()
.ref("/lastSeen/" + userId)
.on("value", (snapshot) => {
setUserLastSeen(snapshot.val());
console.log("User data: ", snapshot.val());
});
console.log("after check last");
};
I tried both the code from firebase docs and rnfirebase docs. In above code, none of the "then" or "catch" functions get called in updateUserLastSeen but in checkUserLastSeen "on" is invoked only if bearer of userId is online. Also, I am using realtime db only for this purpose and cloud firestore for other data storing and its working fine.
Any help would be appreciated. Thanks.

If neither then nor catch of a write is called, it typically means that the client is not connected to the server.
I recommend checking to make sure your app has a network connection, and that you've configured the (correct) URL for your database.

Get the value of a child in firebase using nodejs TypeError

I was wondering if anyone could tell me what I am doing wrong. I am trying to write a firebase function to send a notification. That part works, but I am trying to get the value of a particular child. Yet I keep getting the following error message: "TypeError: Cannot read property 'child' of undefined"
This is my server-side code:
'use strict'
const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);
exports.sendNotification = functions.database.ref('/notifications/{receiver_user_id}/{notification_key}').onWrite((data, context)=>{
const receiver_user_id = context.params.receiver_user_id;
const notification_key = context.params.notification_key;
console.log('We have a notification to send to : ', receiver_user_id);
// Grab the current value of what was written to the Realtime Database.
const original = data.after.val();
console.log('Uppercasing', context.params.notification_key, original);
const sender_fullname = snapshot.child('notifying_user_fullname').val();
console.log('fullname value: ', sender_fullname);
if(!data.after.val()){
console.log('A notification has been deleted: ', notification_key);
return null;
}
const DeviceToken = admin.database().ref(`/tokens/${receiver_user_id}/device_token`).once('value');
return DeviceToken.then(result=>{
const token_id = result.val();
const payload = {
notification: {
title: sender_fullname,
body: "You have a new message!",
icon: "default"
}
};
return admin.messaging().sendToDevice(token_id, payload).then(response=>{
console.log('Message has been sent');
});
});
});
The snapshot prints out just fine. And when I remove the snapshot and sender_fullname constants the notification is delivered just fine. But, like I said, I keep getting a TypeError message when the code is executed this way. Does anyone know how to get the value of a child at a certain location in realtime database. If it helps, this is what the data snapshot looks like:
If anyone can help that would be great. Thank you in advance

You have a variable snapshot that was never defined, at least not that you're showing here. Here's where you're using it:
const sender_fullname = snapshot.child('notifying_user_fullname').val();
Trying to call method on something that's not defined would give you that error message.

How to fix firebase database initialised multiple times due to React SSR initialised database and cloud function firebase initialised database?

I have updated the question as found the root cause of the issue.
As I have hosted my React SSR app which uses firebase database in the client serving by one of the cloud function named app throwing an error of Error: FIREBASE FATAL ERROR: Database initialized multiple times. Please make sure the format of the database URL matches with each database() call.. When I comment out one by one and deploy, works perfectly. But when I deploy together doesn't work. How do I separate these two keeping both at the same repo?
ORIGINAL Question: Why firebase cloud function throwing an error of 'The default Firebase app does not exist.'?
So I am trying out firebase function for the first time. admin.messaging() throwing me the following error. Help me figure out why?
If I look at the console I get results till console.log('deviceToken', deviceToken);
so whats wrong in const messageDone = await admin.messaging().sendToDevice(deviceToken, payload);?
const functions = require('firebase-functions');
const admin = require('firebase-admin');
exports.updateUnreadCount = functions.database.ref('/chats/{chatId}/{messageId}')
.onCreate(async(snap, context) => {
const appOptions = JSON.parse(process.env.FIREBASE_CONFIG);
appOptions.databaseAuthVariableOverride = context.auth;
const adminApp = admin.initializeApp(appOptions, 'app');
const { message, senderId, receiverUid } = snap.val();
console.log(message, senderId, receiverUid);
console.log('------------------------');
const deleteApp = () => adminApp.delete().catch(() => null);
try {
const db = adminApp.database();
const reciverUserRef = await db.ref(`users/${receiverUid}/contacts/${senderId}/`);
console.log('reciverUserRef', reciverUserRef);
const deviceTokenSnapshot = await reciverUserRef.child('deviceToken').once('value');
const deviceToken = await deviceTokenSnapshot.val();
console.log('deviceToken', deviceToken);
const payload = {
notification: {
title: 'Test Notification Title',
body: message,
sound: 'default',
badge: '1'
}
};
const messageDone = await admin.messaging().sendToDevice(deviceToken, payload);
console.log('Successfully sent message: ', JSON.stringify(messageDone));
return deleteApp().then(() => res);
} catch (err) {
console.log('error', err);
return deleteApp().then(() => Promise.reject(err));
}
});
Update1: According to this https://firebase.google.com/docs/cloud-messaging/send-message#send_to_a_topic, admin.messaging().sendToDevice(deviceToken, payload) APIs are only available in the Admin Node.js SDK?
So switched to
const payload = {
data: {
title: 'Test Notification Title',
body: message,
sound: 'default',
badge: '1'
},
token: deviceToken
};
const messageDone = await admin.messaging().send(payload);
Which is not working either. Getting an error Error: The default Firebase app does not exist. Make sure you call initializeApp() before using any of the Firebase services. Any lead will be helpful.
EDIT: Finally got the function working.
My index.js is exporting to functions, follwoing
exports.app = functions.https.onRequest(app); //React SSR
exports.updateChat = functions.database.ref('/chats/{chatId}/{messageId}').onCreate(updateChat);
exports.app is a react ssr function, which I am using to host my site. This uses database too. and throwing error of multiple database instance.
When I comment out one by one and deploy, works perfectly. But when I deploy together doesn't work. How do I separate these two keeping both at the same repo? Any suggestions, please?

You can initialise db outside export function.
const admin = require('firebase-admin');
const adminApp = admin.initializeApp(appOptions, 'app')
//continue code
Update:
const admin = require('firebase-admin');
const adminApp = admin.initializeApp(options);
async function initialize(options, apps = 'app') {
try {
const defaultApp = adminApp.name
if(defaultApp) {
const adminApp1 = admin.initializeApp(apps);
}else {
const adminApp1 = admin.initializeApp(options, apps);
}
}catch(err) {
console.error(err);
}
}
Modify this snippet as per your need and try it out
It abstracts initialize of app in another function. Just call this function at appropriate place in your code.

How to send notification to multiple device token using firebase cloud functions

I am new in using Firebase Cloud Functions and JavaScript and I was able to send notification to a single device using Firebase Cloud Functions(JavaScript). Now I am trying to send push notification to multiple device token and I think I have a problem on it.
I want to send the notification to these device tokens in my firebase database:
/receivers
/event1
/uid1: device_token1
/uid2: device_token2
/uid3: device_token3
/uid4: device_token4
This is my code so far but it doesn't work..
exports.sendSOSNotif = functions.database.ref('/SOSNotifs/{sosId}').onWrite((data, context) => {
const eventId=data.after.child("eventId").val();
const uid=data.after.child("uid").val();
const displayName=data.after.child("displayName").val();
const photoUrl=data.after.child("photoUrl").val();
const status=data.after.child("status").val();
console.log("eventId:", eventId);
console.log("displayName:", displayName);
console.log("uid", uid);
const payload = {
notification: {
title: "SOS Alert",
body: displayName + " sent an alert!",
sound: "default"
},
data: {
eventId: eventId,
displayName: displayName
}
};
return Promise.all([admin.database().ref("/receivers/event1").once('value')]).then(results => {
const tokens = results[0];
if (!tokens.hasChildren()) return null;
const tokensList = Object.keys(tokens.val());
return admin.messaging().sendToDevice(tokensList, payload);
});
});

First of all, you shouldn't be adding tokens like below, if that's how you've organised your DB. There might be multiple token for a single uid
/receivers
/event1
/uid1: device_token1
/uid2: device_token2
/uid3: device_token3
/uid4: device_token4
And for sending notifications to multiple UIDs, I've written a script here
Also, update your question about what exactly the problem you are facing.

Google cloud dialogflow intent detection nodejs example not working

I am trying to implement a very simple dialogflow agent integration with nodejs.
Here is what I did so far
I followed the code from Intent detection
I added the service account private key file .json to my server.
I added the environment variable GOOGLE_APPLICATION_CREDENTIALS with the path to my .json private key file.
Here is the code I am trying to run right now:
require('dotenv').config()
const projectId = 'gg-chatbot-216808';
const sessionId = 'quickstart-session-id';
const query = 'hello';
const languageCode = 'en-US';
// Instantiate a DialogFlow client.
const dialogflow = require('dialogflow');
const sessionClient = new dialogflow.SessionsClient();
// Define session path
const sessionPath = sessionClient.sessionPath(projectId, sessionId);
// The text query request.
const request = {
session: sessionPath,
queryInput: {
text: {
text: query,
languageCode: languageCode,
},
},
};
// This prints the private key path correctly.
console.log(process.env.GOOGLE_APPLICATION_CREDENTIALS);
// Send request and log result
sessionClient
.detectIntent(request)
.then(responses => {
console.log('Detected intent');
const result = responses[0].queryResult;
console.log(` Query: ${result.queryText}`);
console.log(` Response: ${result.fulfillmentText}`);
if (result.intent) {
console.log(` Intent: ${result.intent.displayName}`);
} else {
console.log(` No intent matched.`);
}
})
.catch(err => {
console.error('ERROR:', err);
});
Then I get this error in the console when I run this file
Auth error:Error: invalid_user: Robot is disabled.
ERROR: { Error: 14 UNAVAILABLE: Getting metadata from plugin failed with error: invalid_user: Robot is disabled.
at Object.exports.createStatusError (/var/www/html/google_auth/node_modules/grpc/src/common.js:87:15)
at Object.onReceiveStatus (/var/www/html/google_auth/node_modules/grpc/src/client_interceptors.js:1188:28)
at InterceptingListener._callNext (/var/www/html/google_auth/node_modules/grpc/src/client_interceptors.js:564:42)
at InterceptingListener.onReceiveStatus (/var/www/html/google_auth/node_modules/grpc/src/client_interceptors.js:614:8)
at callback (/var/www/html/google_auth/node_modules/grpc/src/client_interceptors.js:841:24)
code: 14,
metadata: Metadata { _internal_repr: {} },
details: 'Getting metadata from plugin failed with error: invalid_user: Robot is disabled.' }

i also faced a similar issue for my angular bot.
What i did was, instead of using using the google_credentials from the json file, i created an object with private_key,client_email {these values can be taken from the service account private key file .json}, and passed the object while setting up the session client.
var config = {
credentials: {
private_key: "YOUR_PRIVATE_KEY",
client_email: "YOUR_CLIENT_EMAIL"
}
}
const sessionClient = new dialogflow.SessionsClient(config);
note: do copy the full private_key string from .json. It will start as "-----BEGIN PRIVATE KEY-----\n......" .
Also, in GCP go to the project->IAM then try setting role for the service as DIALOGLOW API ADMIN. Check if this works.

If this has not been resolved yet , the solution is to provide "fileKey" inside sessionClient.
const sessionClient = new dialogflow.SessionsClient({
fileKey:" path of your credentials.json file"
});
or
let filePath = process.env.GOOGLE_APPLICATION_CREDENTIALS ="Location of credentials file".
const sessionClient = new dialogflow.SessionsClient({
fileKey:filePath
});
this will even work if there is no system env variable is set as GOOGLE_APPLICATION_CREDENTIALS.
Hope this is helpful.