public static async void LaunchGoogleAuthUri()
{
var state = UtilityService.GenerateRandomDataBase64Url(32);
var codeVerifier = UtilityService.GenerateRandomDataBase64Url(32);
var codeChallenge = UtilityService.EncodeBase64UrlNoPadding(UtilityService.ConvertToSha256(codeVerifier));
const string codeChallengeMethod = "S256";
var localSettings = ApplicationData.Current.LocalSettings;
localSettings.Values["state"] = state;
localSettings.Values["codeVerifier"] = codeVerifier;
var authorizationRequest =
$"{GoogleAuthorizationEndpoint}?response_type=code" +
$"&scope=openid%20profile%20{YouTubeReadOnlyScope}%20{YouTubeUploadScope}" +
$"&redirect_uri={Uri.EscapeDataString(AuthorizationRedirectUri)}" +
$"&client_id={YouTubeApiClientId}" +
$"&state={state}" +
$"&code_challenge={codeChallenge}" +
$"&code_challenge_method={codeChallengeMethod}";
await Launcher.LaunchUriAsync(new Uri(authorizationRequest));
}
/// <summary>
/// Returns URI-safe data with a given input length.
/// </summary>
/// <param name="length">Input length (nb. output will be longer)</param>
/// <returns></returns>
public static string GenerateRandomDataBase64Url(uint length)
{
IBuffer buffer = CryptographicBuffer.GenerateRandom(length);
return(UtilityService.EncodeBase64UrlNoPadding(buffer));
}