How to generate access token using refresh token through Google Drive SDK in .NET?

Question

I have a .NET application that is using Google Drive to access the user\'s file. I am able to get the authorization code, and I have been able to exchange the authorization

Answer 1

If you are using the .NET client library (http://code.google.com/p/google-api-dotnet-client/), you don't have to take care of that. The library will automatically request a new access token for you when needed using the refresh token you retrieved the first time.

Answer 2

I studied a more suitable sample: the Tasks.WinForms.NoteMgr of the GoogleApisSample... and with it I found the solution.

The solution is in the code below. The key part of it is calling arg.RefreshToken(state);

Thanks.

    public static Authentication.IAuthenticator UseSavedAuthorization()
    {          

        var provider = new NativeApplicationClient(GoogleAuthenticationServer.Description);
        provider.ClientIdentifier = ClientID;
        provider.ClientSecret = ClientSecret;

        OAuth2Authenticator<NativeApplicationClient> auth = new OAuth2Authenticator<NativeApplicationClient>(provider, getState);

        auth.LoadAccessToken();

        return auth;             
    }


public static IAuthorizationState getState(NativeApplicationClient arg)
    {
        IAuthorizationState state = new AuthorizationState(new[] { TasksService.Scopes.Tasks.GetStringValue(), 
                DriveService.Scopes.DriveFile.GetStringValue() , DriveService.Scopes.Drive.GetStringValue()
        });
        state.Callback = new Uri(NativeApplicationClient.OutOfBandCallbackUrl);

        state.RefreshToken = "<refresh token previously saved>";        
        arg.RefreshToken(state); 

        return state; 
    }`