GoogleSignIn - How to refresh the access token? Can't find anything on it in the docs

Question

I've successfully integrated GoogleSignIn into my Android app, but after 1 hour, the access token expires. How do I refresh the token?

I've checked out the entire docs for GoogleSignIn but there's nothing on refreshing the accessToken

https://developers.google.com/identity/sign-in/android/start-integrating

I've also tried searching for a method that has something like ".refreshAccessToken()"

How do I refresh the token? Why is there nothing about it in the docs?

Answer 1

The approach below works if you have control of the server powering your Android project. I'll use Java to illustrate since your screenshot is in Java.

From the attached image, I can see that you are able to retrieve GoogleSignInAccount after authenticating the user. You can get a server auth code from this by performing:

String authCode = account.getServerAuthCode();

You can then send this auth code to your server and exchange it for a refresh token using the GoogleAuthorizationCodeTokenRequest class. Here's an illustration below:

String CLIENT_SECRET_FILE = "/path/to/client_secret.json";
String REDIRECT_URI = "" //Leave empty if you don't have a redirect url

GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(JacksonFactory.getDefaultInstance(), new FileReader(CLIENT_SECRET_FILE));  
GoogleTokenResponse tokenResponse = new GoogleAuthorizationCodeTokenRequest(new NetHttpTransport(), JacksonFactory.getDefaultInstance(), "https://www.googleapis.com/oauth2/v4/token", clientSecrets.getDetails().getClientId(), clientSecrets.getDetails().getClientSecret(), authCode, REDIRECT_URI).execute();
 
String accessToken = tokenResponse.getAccessToken();  
String refreshToken = tokenResponse.getRefreshToken();  
Long expiresInSeconds = tokenResponse.getExpiresInSeconds();   

Lastly, you can plug the refresh token to your GoogleCredential like below:

GoogleCredential credential = new GoogleCredential.Builder()  
          .setTransport(new NetHttpTransport())  
          .setJsonFactory(JacksonFactory.getDefaultInstance())  
          .setClientSecrets(clientSecrets)  
          .build();  
 credential.setAccessToken(accessToken);  
 credential.setExpiresInSeconds(expiresInSeconds);  
 credential.setRefreshToken(refreshToken);  

That's it. You can get more information about this process here.