Subramanya c
Posted on December 14, 2019
Hello developers 👏
It's fishy when it comes to merging between the account merging between Google and Facebook. <{❤️}>
What's the issue ?? <{❤️}>
- When signing in with Google, generally all the applications directly allow you to sign-in with your account.
- ex: When you sign-in with an email ex: hello_world@gmail.com
- Let's suppose you have the same email address you use for facebook, when you try signing-in with facebook, it fails with an exception that "ERROR_ACCOUNT_EXISTS_WITH_DIFFERENT_CREDENTIAL", this is because the primary email is always Google for any platform you consider.
- In this case, the dart platform provides an efficient tool called LinkWithCredientials
Here is the dart code for Google authentication <{❤️}>
final GoogleSignInAccount googleSignInAccount =
await googleSignIn.signIn();
final GoogleSignInAuthentication googleSignInAuthentication =
await googleSignInAccount.authentication;
googleCredential = GoogleAuthProvider.getCredential(
accessToken: googleSignInAuthentication.accessToken,
idToken: googleSignInAuthentication.idToken,
);
detail = await GlobalVariables.firebaseAuth
.signInWithCredential(googleCredential);
`
Here is the dart code for Facebook authentication <{❤️}>
`
final result = await facebookLogin
.logIn(['email', 'public_profile', 'user_friends']);
switch (result.status) {
case FacebookLoginStatus.error:
break;
case FacebookLoginStatus.cancelledByUser:
break;
case FacebookLoginStatus.loggedIn:
final token = result.accessToken.token;
final graphResponse = await http.get(
'https://graph.facebook.com/v2.12/me?fields=name,picture.width(800).height(800),first_name,last_name,email&access_token=$token');
final profile = await json.decode(graphResponse.body);
facebookCredential =
FacebookAuthProvider.getCredential(accessToken: token);
GlobalVariables.firebaseUser =
await GlobalVariables.firebaseAuth.currentUser();
try {
details = await GlobalVariables.firebaseAuth
.signInWithCredential(facebookCredential);
`
- Now the above code throws an exception if the account has already been signed in with Google. To overcome this error use the try-catch block and embed the code inside it. Now when the exception is caught by try-catch use the code to check if the exception is the same as I have mentioned above, and use the proper creds.
`
catchError((onError) {
if (onError.code ==
"ERROR_ACCOUNT_EXISTS_WITH_DIFFERENT_CREDENTIAL") {
GlobalVariables.firebaseAuth
.fetchSignInMethodsForEmail(email: profile['email'])
.then((data) async {
final GoogleSignInAccount googleSignInAccount =
await googleSignIn.signIn();
final GoogleSignInAuthentication googleSignInAuthentication =
await googleSignInAccount.authentication;
googleCredential = GoogleAuthProvider.getCredential(
accessToken: googleSignInAuthentication.accessToken,
idToken: googleSignInAuthentication.idToken,
);
GlobalVariables.firebaseAuth
.signInWithCredential(googleCredential).then((data) {
var user = data.user;
user.linkWithCredential(facebookCredential);
}
});
This is the simple solution. Though the documentation of firebase says it all, practically they have not shown it for the dart.
💖 💪 🙅 🚩
Subramanya c
Posted on December 14, 2019
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