You can let your users authenticate with Firebase using their Twitter accounts
by integrating Twitter authentication into your app. You can integrate Twitter
authentication either by using the Firebase SDK to carry out the sign-in flow,
or by carrying out the Twitter OAuth flow manually and passing the resulting
access token and secret to Firebase.
Before you begin
- Add Firebase to your JavaScript project
.
- In the
Firebase console
, open the
Auth
section.
- On the
Sign in method
tab, enable the
Twitter
provider.
- Add the
API key
and
API secret
from that provider's developer console to the
provider configuration:
- Register your app
as a developer application on Twitter and get your app's OAuth
API key
and
API secret
.
- Make sure your Firebase
OAuth redirect URI
(e.g.
my-app-12345.firebaseapp.com/__/auth/handler
)
is set as your
Authorization callback URL
in your app's settings page on your
Twitter app's config
.
- Click
Save
.
Handle the sign-in flow with the Firebase SDK
If you are building a web app, the easiest way to authenticate your users
with Firebase using their Twitter accounts is to handle the sign-in flow with
the Firebase JavaScript SDK. (If you want to authenticate a user in Node.js
or other non-browser environment, you must handle the sign-in flow manually.)
To handle the sign-in flow with the Firebase JavaScript SDK, follow these
steps:
- Create an instance of the Twitter provider object:
Web modular API
import { TwitterAuthProvider } from "firebase/auth";
const provider = new TwitterAuthProvider();
Web namespaced API
var provider = new firebase.auth.TwitterAuthProvider();
- Optional
: To localize the provider's OAuth flow to the user's preferred
language without explicitly passing the relevant custom OAuth parameters, update the language
code on the Auth instance before starting the OAuth flow. For example:
Web modular API
import { getAuth } from "firebase/auth";
const auth = getAuth();
auth.languageCode = 'it';
// To apply the default browser preference instead of explicitly setting it.
// auth.useDeviceLanguage();
Web namespaced API
firebase.auth().languageCode = 'it';
// To apply the default browser preference instead of explicitly setting it.
// firebase.auth().useDeviceLanguage();
- Optional
: Specify additional custom OAuth provider parameters
that you want to send with the OAuth request. To add a custom parameter, call
setCustomParameters
on the initialized provider with an object containing the key
as specified by the OAuth provider documentation and the corresponding value. For example:
Web modular API
provider.setCustomParameters({
'lang': 'es'
});
Web namespaced API
provider.setCustomParameters({
'lang': 'es'
});
Reserved required OAuth parameters are not allowed and will be ignored.
See the
authentication provider reference
for more details.
- Authenticate with Firebase using the Twitter provider object. You can
prompt your users to sign in with their Twitter accounts either by opening a
pop-up window or by redirecting to the sign-in page. The redirect method is
preferred on mobile devices.
Handling account-exists-with-different-credential Errors
If you enabled the
One account per email address
setting in the
Firebase console
,
when a user tries to sign in a to a provider (such as Twitter) with an email that already
exists for another Firebase user's provider (such as Google), the error
auth/account-exists-with-different-credential
is thrown along with an
AuthCredential
object (Twitter oauth token and secret). To complete the sign in to the
intended provider, the user has to sign first to the existing provider (Google) and then link to the
former
AuthCredential
(Twitter oauth token and secret).
If you use
signInWithPopup
, you can handle
auth/account-exists-with-different-credential
errors with code like the following
example:
import {
getAuth,
linkWithCredential,
signInWithPopup,
TwitterAuthProvider,
} from "firebase/auth";
try {
// Step 1: User tries to sign in using Twitter.
let result = await signInWithPopup(getAuth(), new TwitterAuthProvider());
} catch (error) {
// Step 2: User's email already exists.
if (error.code === "auth/account-exists-with-different-credential") {
// The pending Twitter credential.
let pendingCred = error.credential;
// Step 3: Save the pending credential in temporary storage,
// Step 4: Let the user know that they already have an account
// but with a different provider, and let them choose another
// sign-in method.
}
}
// ...
try {
// Step 5: Sign the user in using their chosen method.
let result = await signInWithPopup(getAuth(), userSelectedProvider);
// Step 6: Link to the Twitter credential.
// TODO: implement `retrievePendingCred` for your app.
let pendingCred = retrievePendingCred();
if (pendingCred !== null) {
// As you have access to the pending credential, you can directly call the
// link method.
let user = await linkWithCredential(result.user, pendingCred);
}
// Step 7: Continue to app.
} catch (error) {
// ...
}
Redirect mode
This error is handled in a similar way in the redirect mode, with the difference that the pending
credential has to be cached between page redirects (for example, using session storage).
Handle the sign-in flow manually
You can also authenticate with Firebase using a Twitter account by handling the
sign-in flow by calling the Twitter OAuth endpoints:
- Integrate Twitter authentication into your app by following the
developer's documentation
. At the end of the Twitter sign-in flow, you
will receive an OAuth access token and an OAuth secret.
- If you need to sign in on a Node.js application, send the OAuth access
token and the OAuth secret to the Node.js application.
- After a user successfully signs in with Twitter, exchange the OAuth access
token and OAuth secret for a Firebase credential:
var credential = firebase.auth.TwitterAuthProvider.credential(token, secret);
- Authenticate with Firebase using the Firebase credential:
Web modular API
import { getAuth, signInWithCredential, FacebookAuthProvider } from "firebase/auth";
// Sign in with the credential from the Facebook user.
const auth = getAuth();
signInWithCredential(auth, credential)
.then((result) => {
// Signed in
const credential = FacebookAuthProvider.credentialFromResult(result);
})
.catch((error) => {
// Handle Errors here.
const errorCode = error.code;
const errorMessage = error.message;
// The email of the user's account used.
const email = error.customData.email;
// The AuthCredential type that was used.
const credential = FacebookAuthProvider.credentialFromError(error);
// ...
});
Web namespaced API
// Sign in with the credential from the Facebook user.
firebase.auth().signInWithCredential(credential)
.then((result) => {
// Signed in
var credential = result.credential;
// ...
})
.catch((error) => {
// Handle Errors here.
var errorCode = error.code;
var errorMessage = error.message;
// The email of the user's account used.
var email = error.email;
// The firebase.auth.AuthCredential type that was used.
var credential = error.credential;
// ...
});
Authenticate with Firebase in a Chrome extension
If you are building a Chrome extension app, see the
Offscreen Documents guide
.
Customizing the redirect domain for Twitter sign-in
On project creation, Firebase will provision a unique subdomain for your project:
https://my-app-12345.firebaseapp.com
.
This will also be used as the redirect mechanism for OAuth sign in. That domain would need to be
allowed for all supported OAuth providers. However, this means that users may see that
domain while signing in to Twitter before redirecting back to the application:
Continue to: https://my-app-12345.firebaseapp.com
.
To avoid displaying your subdomain, you can set up a custom domain with Firebase Hosting:
- Follow steps 1 through 3 in
Set up your domain for Hosting
. When you verify
your domain ownership, Hosting provisions an SSL certificate for your custom domain.
- Add your custom domain to the list of authorized domains in the
Firebase console
:
auth.custom.domain.com
.
- In the Twitter developer console or OAuth setup page, whitelist the URL of the redirect page,
which will be accessible on your custom domain:
https://auth.custom.domain.com/__/auth/handler
.
- When you initialize the JavaScript library, specify your custom domain with the
authDomain
field:
var config = {
apiKey: '...',
// Changed from 'my-app-12345.firebaseapp.com'.
authDomain: 'auth.custom.domain.com',
databaseURL: 'https://my-app-12345.firebaseio.com',
projectId: 'my-app-12345',
storageBucket: 'my-app-12345.appspot.com',
messagingSenderId: '1234567890'
};
firebase.initializeApp(config);
Next steps
After a user signs in for the first time, a new user account is created and
linked to the credentials—that is, the user name and password, phone
number, or auth provider information—the user signed in with. This new
account is stored as part of your Firebase project, and can be used to identify
a user across every app in your project, regardless of how the user signs in.
-
In your apps, the recommended way to know the auth status of your user is to
set an observer on the
Auth
object. You can then get the user's
basic profile information from the
User
object. See
Manage Users
.
In your Firebase Realtime Database and Cloud Storage
Security Rules
, you can
get the signed-in user's unique user ID from the
auth
variable,
and use it to control what data a user can access.
You can allow users to sign in to your app using multiple authentication
providers by
linking auth provider credentials to an
existing user account.
To sign out a user, call
signOut
:
Web modular API
import { getAuth, signOut } from "firebase/auth";
const auth = getAuth();
signOut(auth).then(() => {
// Sign-out successful.
}).catch((error) => {
// An error happened.
});
Web namespaced API
firebase.auth().signOut().then(() => {
// Sign-out successful.
}).catch((error) => {
// An error happened.
});