ApplicationDefaultCredentials obtains the default credentials for authorizing a request to a Google service.

Application Default Credentials are described here: https://developers.google.com/accounts/docs/application-default-credentials

This class implements the search for the application default credentials as described in the link.

It provides three factory methods:

• get returns the computed credentials object

• getSubscriber returns an AuthTokenSubscriber built from the credentials object

• getMiddleware returns an AuthTokenMiddleware built from the credentials object

This allows it to be used as follows with GuzzleHttp\Client:

use Google\Auth\ApplicationDefaultCredentials; use GuzzleHttp\Client; use GuzzleHttp\HandlerStack;

$middleware = ApplicationDefaultCredentials::getMiddleware( 'https://www.googleapis.com/auth/taskqueue' ); $stack = HandlerStack::create(); $stack->push($middleware);

$client = new Client([ 'handler' => $stack, 'base_uri' => 'https://www.googleapis.com/taskqueue/v1beta2/projects/', 'auth' => 'google_auth' // authorize all requests ]);

$res = $client->get('myproject/taskqueues/myqueue');