Uploading videos to a YouTube account without a channel fails.
I'm using the YouTube Data API (Version 3) and the Google APIs Client Library for PHP to upload custom videos to a users channel. The user has given authorization (via OAuth2) to manage their YouTube account, but it's possible that the user has never created a YouTube channel.
The question is: How do I check if the user has a valid channel before trying to start an upload? Ideally, I'd want to check right after authentication.