Google+ API: How can I use RefreshTokens to avoid requesting access every time my app launches?

Question

I\'m trying to use the Google+ API to access info for the authenticated user. I\'ve copied some code from one of the samples, which works fine (below), however I\'m having t

Answer 1

Here is an example. Make sure you add a string setting called RefreshToken and reference System.Security or find another way to safely store the refresh token.

    private static byte[] aditionalEntropy = { 1, 2, 3, 4, 5 };

    private static IAuthorizationState GetAuthorization(NativeApplicationClient arg)
    {
        // Get the auth URL:
        IAuthorizationState state = new AuthorizationState(new[] { PlusService.Scopes.PlusMe.GetStringValue() });
        state.Callback = new Uri(NativeApplicationClient.OutOfBandCallbackUrl);

        string refreshToken = LoadRefreshToken();
        if (!String.IsNullOrWhiteSpace(refreshToken))
        {
            state.RefreshToken = refreshToken;

            if (arg.RefreshToken(state))
                return state;
        }

        Uri authUri = arg.RequestUserAuthorization(state);

        // Request authorization from the user (by opening a browser window):
        Process.Start(authUri.ToString());
        Console.Write("  Authorization Code: ");
        string authCode = Console.ReadLine();
        Console.WriteLine();

        // Retrieve the access token by using the authorization code:
        var result = arg.ProcessUserAuthorization(authCode, state);

        StoreRefreshToken(state);
        return result;
    }

    private static string LoadRefreshToken()
    {
        return Encoding.Unicode.GetString(ProtectedData.Unprotect(Convert.FromBase64String(Properties.Settings.Default.RefreshToken), aditionalEntropy, DataProtectionScope.CurrentUser));
    }

    private static void StoreRefreshToken(IAuthorizationState state)
    {
        Properties.Settings.Default.RefreshToken = Convert.ToBase64String(ProtectedData.Protect(Encoding.Unicode.GetBytes(state.RefreshToken), aditionalEntropy, DataProtectionScope.CurrentUser));
        Properties.Settings.Default.Save();
    }