node.js - Firebase admin on backend for verifyIdToken and use Firestore

Question

I'm trying to use Firebase Admin on my backend for "faking" client authentication by verifying Id Token in order to use firestore from the backend.

The idea is to use my server as a middleware between my client and firestore.

I can initialize FirebaseAdmin on the backend and verifyIdToken() from client properly, but I don't have an idea for using firestore after that. Can you guys show me a way for doing it?

import * as firebaseAdmin from 'firebase-admin';
import firebaseServiceAccountKey from './firebaseServiceAccountKey.json';

if (!firebaseAdmin.apps.length) {
  firebaseAdmin.initializeApp({
    credential: firebaseAdmin.credential.cert(
      firebaseServiceAccountKey
    ),
    databaseURL: ##########################,
  });
}

// This is working 
function getUser(token) {
  return firebaseAdmin
    .auth()
    .verifyIdToken(token)
    .then((decodedToken) => {
      return decodedToken;
    })
    .catch((error) => {
      return error
    });
}

/* 
Now I want to use Firestore authenticated with this token, should I 
import firebase from "firebase" 
and then try auth() with token?
*/

Answer 1

Waitting for answers