How can I log in a user right after his/her email has been verified using firebase/auth and react-native without creating a whole landing page? - firebase

Question

Notice: I have seen this question, but creating a whole landing page just to verify a user seems a bit much.
I added a login functionality to my react-native app using firebase/auth with email and password. This works well so far and I have no issues doing that.
I then continued to send a verification email to a new user and only allow him/her to use the app, once the email is verified. Again, no issues here.
The next step would be to login the user right after the email was verified. This is where I'm stuck, since the onAuthStateChanged eventhandler doesn't update after the user pressed the verification link in the email.
Is there any way to listen to the emailVerified state in real-time? I tried to use polling with setInterval() but this is not great since there is a notable delay between verification and login. I read about a continueLink you can pass to sendEmailVerification, but I couldn't figure out how to make that work in react-native.
I'm using Expo and therefore the Firebase SDK, not the Firebase react native package.
Here is the code I use for the signup:
export const signUp = async (username: string, email: string, password: string) => {
try {
const auth = getAuth();
if (email && password && username) {
// sign up
const userCredential = await createUserWithEmailAndPassword(auth, email, password);
// save username in firestore
await setUserName(userCredential, username);
// send Email Verification
await sendEmailVerification(userCredential.user);
return true;
}
} catch (error) {
onError(error);
}
};
And this is my onAuthStateChanged handler:
auth.onAuthStateChanged(authenticatedUser => {
try {
if (authenticatedUser?.emailVerified) {
setUser(authenticatedUser)
} else {
setUser(null)
}
} catch (error) {
console.log(error);
}
});

Answer 1

So in the end I did follow this question, but I changed it a bit to fit my needs. I'll post my steps for anyone who's doing the same.
Create a simple static website with firebase init and host it on firebase or somewhere else (check the hosting tab in your firebase console to get started)
Follow this guide to create the appropriate handlers on the website
Add the following to your verificationHandler to update the user (don't forget to import firestore) (I send the userId via the continueURL, but there are probably better ways)
// You can also use realtime database if you want
firebase.firestore().collection("users").doc(userId).set({
emailVerified: true
}, {merge: true}).then(() => {
message.textContent = "Your email has been verified.";
}).catch((error) => {
message.textContent = "The verification was invalid or is expired. Please try to send another verification email from within the app.";
});
Got to authentication -> templates in your firebase console and change the action url to your hosted website's url
Add a listener to the firestore doc to your react-native app
const onUserDataChanged = (uid, callback) => {
onSnapshot(doc(firestore, "users", uid), doc => callback(doc.data()));
}
Use the data from the callback to update the login state in the app
// As an example
auth.onAuthStateChanged(authenticatedUser => {
if (authenticatedUser && !authenticatedUser.emailVerified) {
unsubscribeFirestoreListener?.();
unsubscribeFirestoreListener = onUserDataChanged(authenticatedUser.uid, (data: any) => {
if (data?.emailVerified) {
setUser(authenticatedUser);
unsubscribeFirestoreListener?.();
}
});
}
}

Answer 2

use the codes below for your authentication context. for user id, you should use 'user.uid'
import React, { useState, createContext } from "react";
import * as firebase from "firebase";
import { loginRequest } from "./authentication.service";
export const AuthenticationContext = createContext();
export const AuthenticationContextProvider = ({ children }) => {
const [isLoading, setIsLoading] = useState(false);
const [user, setUser] = useState(null);
const [error, setError] = useState(null);
firebase.auth().onAuthStateChanged((usr) => {
if (usr) {
setUser(usr);
setIsLoading(false);
} else {
setIsLoading(false);
}
});
const onLogin = (email, password) => {
setIsLoading(true);
firebase.auth().signInWithEmailAndPassword(email, password)
.then((u) => {
setUser(u);
setIsLoading(false);
})
.catch((e) => {
setIsLoading(false);
setError(e.toString());
});
};
const onRegister = (email, password, repeatedPassword) => {
setIsLoading(true);
if (password !== repeatedPassword) {
setError("Error: Passwords do not match");
return;
}
firebase
.auth()
.createUserWithEmailAndPassword(email, password)
.then((u) => {
setUser(u);
setIsLoading(false);
})
.catch((e) => {
setIsLoading(false);
setError(e.toString());
});
};
const onLogout = () => {
setUser(null);
firebase.auth().signOut();
};
return (
<AuthenticationContext.Provider
value={{
isAuthenticated: !!user,
user,
isLoading,
error,
onLogin,
onRegister,
onLogout,
}}
>
{children}
</AuthenticationContext.Provider>
);
};