PHP Google_Client插入youtube playlistItem（2-leg-oauth）

Question

My web using the PHP Google_Client to insert the youtube playlistItem in my playlist (2-leg-oauth), and get the error Client is unauthorized to retrieve access tokens using this method. Where can I setting the server using [e-mail] to have the same permission to access google api such like insert playlistItem, or is there having another way without using [e-mail] to get same permission?

PHP Code:

putenv('GOOGLE_APPLICATION_CREDENTIALS=client_secret.json');
$client = new Google_Client();
$client->useApplicationDefaultCredentials();
$client->addScope('https://www.googleapis.com/auth/youtube');
$client->setSubject('[e-mail]');

Answer 1

If you have delegated domain-wide access to the service account and you want to impersonate a user account, specify the email address of the user account use

$client->setSubject($user_to_impersonate);

The YouTube API doesn't support delegated domain-wide access or service accounts. You will need to authenticate with Oauth2.

see PHP Code Samples