Is there any way to get Firebase Auth User UID?

Question

I am looking to fetch Auth User(s) UID from Firebase via NodeJS or Javascript API. I have attached screenshot for it so that you will have idea what I am looking for.

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Answer 1

From Firebase docs, use Firebase.getAuth():

var ref = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com");
var authData = ref.getAuth();

if (authData) {
  console.log("Authenticated user with uid:", authData.uid);
}

Source:

• Firebase.getAuth()

Answer 2

on server side you can use firebase admin sdk to get all user information :

const admin = require('firebase-admin')
var serviceAccount = require("./serviceAccountKey.json");

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: "https://yourprojecturl.firebaseio.com",
});

admin.auth().listUsers().then(data=>{
    console.log(data.users)
})

Answer 3

As of now in Firebase console, there is no direct API to get a list of users, Auth User(s) UID.
But inside your Firebase database, you can maintain the User UID at user level. As below,

"users": {
  "user-1": {
    "uid": "abcd..",
    ....
  },
  "user-2": {
    "uid": "abcd..",
    ....
  },
  "user-3": {
    "uid": "abcd..",
    ....
  }
}

Then you can make a query and retrieve it whenever you need uid's.
Hope this simple solution could help you!

Answer 4

Auth data is asynchronous in Firebase 3. So you need to wait for the event and then you have access to the current logged in user's UID. You won't be able to get the others. It will get called when the app opens too.

You can also render your app only once receiving the event if you prefer, to avoid extra logic in there to determine if the event has fired yet.

You could also trigger route changes from here based on the presence of user, this combined with a check before loading a route is a solid way to ensure only the right people are viewing publicOnly or privateOnly pages.

firebase.auth().onAuthStateChanged((user) => {
  if (user) {
    // User logged in already or has just logged in.
    console.log(user.uid);
  } else {
    // User not logged in or has just logged out.
  }
});

Within your app you can either save this user object, or get the current user at any time with firebase.auth().currentUser.

https://firebase.google.com/docs/reference/js/firebase.auth.Auth#onAuthStateChanged

Answer 5

if a user is logged in then the console.log will print out:

if (firebase.auth().currentUser !== null) 
        console.log("user id: " + firebase.auth().currentUser.uid);