Question

I got the refresh token and access token from the authorization code by using the sample program given here https://developers.google.com/drive/credentials#retrieve_oauth_20_credentials

But there is no sample program to get the access token from refresh token i.e., when we dont have authorization code. Any pointers? Is there any way to Instantiate a drive service object using only refresh token and access token?

Answer 1

The DrEdit Java sample has an example on how to retrieve stored Credentials from the Google App Engine Datastore.

If using another type of credentials store, you can use the following code to instantiate new OAuth 2.0 Credentials using stored tokens:

GoogleCredential credentials = new GoogleCredential.Builder()
    .setClientSecrets(CLIENT_ID, CLIENT_SECRET)
    .setJsonFactory(jsonFactory).setTransport(transport).build()
    .setRefreshToken("<REFRESH_TOKEN>").setAccessToken("<ACCESS_TOKEN>");

EDIT: Corrected a typo in the code.