google-api-php-client“错误”：“unauthorized_client”

Question

We are trying to build a service to export google drive files for in our gsuite domain.

We're working with the https://github.com/google/google-api-php-client

We made a service user, downloaded and saved the user credentials and granted domain-wide-access to the service user.

With the simplest example like below (like in every doc, i found):

putenv('GOOGLE_APPLICATION_CREDENTIALS='/service-account-credentials.json');

$client = new \Google_Client();
$client->setAuthConfig('service-account-credentials.json');

$client->setScopes('https://www.googleapis.com/auth/drive.file');

$client->useApplicationDefaultCredentials();
$client->setSubject('admin@mydomain.com');

$service = new \Google_Service_Drive($client);

$service->files->listFiles(); 

as soon as we include the line $client->setSubject('admin@mydomain.com'); it's dropping the following error:

{
    "error": "unauthorized_client",
    "error_description": "Client is unauthorized to retrieve access tokens using this method."
}

has anyone an idea, or can share a code sample for this problem. It's a real blocker for us and for now I don't have any idea why this error appears

Answer 1

I finally made it

After a couple of trys I realized I was delegating domain-wide-access to the wrong Client-ID. I always thought this should be the same as the "client_email" I'm using in the script. But it is really (really, really, really) important, that this is the "client_id" (as mentioned in the documentation by the way). This is not an email or a string it's just a simple number you get when you create a key for the Service Account.