How to use my firebase authentication to work with external services? - firebase

Question

Ok so I am using firebase as authentication for my iOS app. Now I plan on adding video calling to my app using an external service know as connectyCube. This service has their own authentication system and I cannot use their services unless a user is authenticated.
Option 1: I can use their own authentication which means my app would have two authentication systems - not very productive
Option 2: They say I can use an existing authentication to validate users
I understand that this is a common thing in the developers world and I see the word OAuth and JWT being thrown around but I am a rookie developer and I want to understand how I can use firebase and authenticate a user from an external service.
These are the questions they have asked when I opted for the "I have my own authentication" option:
What is your end point URL
Is it GET or POST
Request Headers
Request Params
Response Params
Where do I get all this information from firebase? Any help would be great

Answer 1

As an alternative to #Dharmaraj's answer, you could instead make use of a HTTP Event Cloud Function for this based on the code sample they've provided.
Using this method, you create the endpoint /verifyUserToken to be used by ConnectyCube.
import * as functions from "firebase-functions";
import * as admin from "firebase-admin";
admin.initializeApp();
export const verifyUserToken = functions.https.onRequest((req, res) => {
const idToken = req.query.token;
verifyUser(idToken)
.then(
(userData) => {
res.status(200).json(userData)
},
(err) => {
console.log("Token verification failed.", err.code || err.message);
res.status(422).json({error: "User token is invalid"})
}
)
.catch((err) => console.error("Unexpected crash", err));
});
async function verifyUser(token) {
if (!token)
throw new Error("token missing");
// using `true` here to force token to be checked against the Firebase
// Auth API rather than trusting its contents as-is
const { uid, email } = await admin.auth().verifyIdToken(token, true);
// pull the user's username from their user data
// at /users/{userId}/username
const username = (await admin.database().ref("users/" + uid + "/username")).val();
// use user's actual email if available, otherwise fallback
// to a userID based email
const uEmail = email || uid + "#users.noreply.yourapp.com";
// use user's username if available, otherwise fallback to
// the email address above.
const uLogin = username !== null ? username : uEmail;
return {
uid,
login: uLogin,
email: uEmail,
user: {id: uid, login: uLogin, email: uEmail}, // <- this part in particular is used by ConnectyCube
users: [{uid, login: uLogin, email: uEmail}]
};
}
Once deployed, you would use the following settings:
Setting
Value
API URL:
https://us-central1-PROJECT-ID.cloudfunctions.net/verifyUserToken
GET/POST
GET
Request params:
{"token": "#{login}"}
Response params:
{"uid": "#{user.id}", "email": #{user.email}, "login": "#{user.login}"}

Answer 2

It looks like ConnectyCube uses some sort of Session Tokens as mentioned in their documentation with their own username and password.
The most easiest way would be creating a ConnectyCube account whenever a new user signs up in your Firebase app using Firebase Auth Triggers for Cloud functions. Then you can generate username and password on behalf of your user and store them in a Database.
So whenever you need to create a ConnectyCube session, check for the currently logged in user and fetch their ConnectyCube credentials.
async function createCCSession() {
const userId = firebase.auth().currentUser.uid
const ccCrednetials = (await firebase.database().ref(`ccCreds/${userId}`).once('value')).val()
ConnectyCube.createSession(ccCredentials)
.then((session) => {
console.log(session)
return session
}).catch((error) => console.log(error));
}
You can protect the database using security rules so a user can access their credentials only.
{
"rules": {
"ccCreds": {
"$uid": {
".read": "$uid === auth.uid"
}
}
}
}

Answer 3

While I don't normally double-answer a question, in the course of exploring some other authentication related problems, I've managed to eliminate the Cloud Function from my other answer entirely and instead call the Authentication API directly.
Setting
Value
API URL:
https://www.googleapis.com/identitytoolkit/v3/relyingparty/getAccountInfo?key=FIREBASE_CONFIG_API_KEY
GET/POST
POST
Request params:
{"idToken": "#{login}"}
Response params:
{"uid": "#{users.0.localId}", "email": #{users.0.email}, "full_name": "#{users.0.displayName}"}
On your client, you just call the ConnectyCube Login API with the following data:
POST https://api.connectycube.com/login
login=<Firebase-ID-token>
password=<any-random-value-to-pass-the-validation>