I am building an app that calls Twitter API from Cloud Functions. The user's access token is stored in Firebase RTDB.

The problem is that when I don't call Firebase's Auth sign in method, the database returns a null snapshot.

When I do call Firebase's Auth sign in (code below), it works as normal

const functions = require("firebase-functions");
const Twitter = require('twitter');
const admin = require('firebase-admin');
const cors = require('cors')({ origin: true });
admin.initializeApp();



exports.tweet = functions.https.onRequest(async (req, res) => {
    console.log('devs do something', req.body)
    cors(req, res, () => {
        if (req.body.uid) {
            var uid = req.body.uid
            var promise = admin.database().ref(`auth/`).child(uid).once('value');
            return promise.then(snapshot => {
                var event = snapshot.val()
                
                const client = new Twitter({
                    access_token_key: event.accessToken,
                    access_token_secret: event.secret,
                    consumer_key: "HUYEtFs1NJVGlFqBDq7GJ6HF2",//functions.config().twitter.key,
                    consumer_secret: "ChcSAVwBbd4wLXBSZlIu6nUi6mjsk4b6HqoivuhziP3zAkgGni"//functions.config().twitter.secret
                    //consumer_token_secret: "ChcSAVwBbd4wLXBSZlIu6nUi6mjsk4b6HqoivuhziP3zAkgGni"//functions.config().twitter.secret
                });
                var params = {
                   "tweet_mode": "extended"
                }
                client.get('statuses/home_timeline', params, function(error, tweets, response) {
                 
                    if (error) throw error;
                    res.send(tweets)
                });
    
             })
        } else {
            console.log("No UID provided")
        }

    })
})

This code only works when the below function is called first. If it is not called, then admin.database().ref('auth/${uid}') returns a null snapshot.

The below code redirects user to sign in with Twitter Popup, which is inconvenient every single time.

  async login(context) {
    console.log("auth.login()");
    return await auth
        .signInWithPopup(provider)
        .then(async (result) => {
            // This gives you a the Twitter OAuth 1.0 Access Token and Secret.
            // You can use these server side with your app's credentials to access the Twitter API.
            var credential = result.credential;
            var accessToken = credential.accessToken;
            var secret = credential.secret;

            // The signed-in user info.
            var user = result.user;
           
            db.ref(`auth/${user.uid}/`).update({ accessToken, secret })

            return user
            // ...
        })

Is there a connection between Firebase Auth and Firebase Admin that I am unaware of?