Understanding which authentication method a user has used can be useful for several reasons. For example, it can be leveraged for analytics, user support, and to customize the user's experience based on their login method. This method, however, is specific to Firebase Authentication.
โ
In our Flutter app, we can find out which method a user used to authenticate by leveraging Firebase's User.providerData property. Let's take a closer look at how this works in the code:
import 'package:firebase_auth/firebase_auth.dart';
String getUserSignInMethod() {
final user = FirebaseAuth.instance.currentUser;
String signInMethod;
for (var info in user.providerData) {
signInMethod = info.providerId;
}
return signInMethod;
}
Here's a breakdown of the code:
We first import the FirebaseAuth package which gives us access to Firebase's authentication methods.
Next, we define a function
getUserSignInMethod
. This function will return a string indicating the sign-in method the user used.Inside the function, we obtain the current user from FirebaseAuth using
FirebaseAuth.instance.currentUser
.We then declare a string
signInMethod
that will store the name of the provider used for sign-in.user.providerData
is an iterable that provides UserInfo for each sign-in method used by the user. We loop over this iterable using afor
loop.In each iteration, we assign the
providerId
to oursignInMethod
string. TheproviderId
can be 'google.com' for Google, 'facebook.com' for Facebook, and 'password' for email and password.After the loop is done, the function returns
signInMethod
string which indicates the sign-in method the user used.
The function getUserSignInMethod()
returns a String value which corresponds to the providerId of the user's sign-in method.
Here are examples of how the return value might look:
If the user has signed in using Google, the function will return:
'google.com'
If the user has signed in using Facebook, the function will return:
'facebook.com'
If the user has signed in using Email and Password, the function will return:
'password'
These are the identifiers used by Firebase to represent different sign-in methods.
โ
Please, thoroughly test this function to ensure it fits your specific requirements.
For more details, you can refer to Firebase's official documentation, as well as our documentation, community tutorials, Youtube channel, blog, and intercom articles.