private void VerifyAndRefreshCredentials(TransientCredentials tc)
{
var userCredential = tc.Token as UserCredential;
var token = userCredential?.Token;
if (IsValidToken(token))
{
// We already have a valid OAuth token.
return;
}
if (userCredential == null)
{
// Attempt to load a cached OAuth token.
var flow = new GoogleAuthorizationCodeFlow(new GoogleAuthorizationCodeFlow.Initializer
{
ClientSecretsStream = ClientSecretsStream,
DataStore = GetCredentialsDataStoreForBlog(tc.Username),
Scopes = new List<string>() { BloggerServiceScope, PicasaServiceScope },
});
var loadTokenTask = flow.LoadTokenAsync(tc.Username, CancellationToken.None);
loadTokenTask.Wait();
if (loadTokenTask.IsCompleted)
{
// We were able re-create the user credentials from the cache.
userCredential = new UserCredential(flow, tc.Username, loadTokenTask.Result);
token = loadTokenTask.Result;
}
}
if (!IsValidToken(token))
{
// The token is invalid, so we need to login again. This likely includes popping out a new browser window.
if (BlogClientUIContext.SilentModeForCurrentThread)
{
// If we're in silent mode where prompting isn't allowed, throw the verification exception
throw new BlogClientAuthenticationException(String.Empty, String.Empty);
}
// Start an OAuth flow to renew the credentials.
var authorizationTask = GetOAuth2AuthorizationAsync(tc.Username, CancellationToken.None);
authorizationTask.Wait();
if (authorizationTask.IsCompleted)
{
userCredential = authorizationTask.Result;
token = userCredential?.Token;
}
}
if (!IsValidToken(token))
{
// The token is still invalid after all of our attempts to refresh it. The user did not complete the
// authorization flow, so we interpret that as a cancellation.
throw new BlogClientOperationCancelledException();
}
// Stash the valid user credentials.
tc.Token = userCredential;
}
