Adds a video to the YouTube playlist whose ID is stored in the passed Credentials.
Request OAuth API tokens from Google.
Refreshes the OAuth API token in the passed Google credentials.
Requests a Google API authorisation code from Google servers, then uses it to obtain an access key and a refresh OAuth key.
Validates a Google OAuth token, returning the JSON received from the server.
JSON schema for the Google error response.
JSON schema for the Google plain error response.
JSON schema for the Google token response.
Bits and bobs to get Google API credentials and for YouTube playlist management.