Allow setting an account for requests impersonification when using service accounts

[velPL]

The https://github.com/googleapis/google-api-php-client library allows to authenticate using Service Accounts keys in JSON format and also impersonificate another user within a domain (which requires domain-wide delegation to be enabled). This is simply done as:

$client = new Google_Client();
$client->setSubject('address_to_act_as@example.com');

Could we please have this functionality as well in this library? From what I've seen there is a class \Google\Auth\Credentials\ServiceAccountCredentials with a constructor's 3rd argument for setting impersonation subject but this is never used/referenced. What's more - hardcoding a valid address to impersonate also fails with the permission denied for provided property id - error code 7.

[bshaffer]

If you look at the code in Google\Client.php, it uses the same class you're referring to, ServiceAccountCredentials, to set the subject. So using that class and supplying the subject to its constructor would hav the same efect:

$credentials = new Google\Auth\Credentials\ServiceAccountCredentials($scope, $credFile, $subject);
// the configuration option may be different depending on the client
$bigquery = new Google\Cloud\BigQuery\BigQueryClient(['credentialsFetcher' => $credentials]);
$analytics = new Google\Cloud\AnalyticsData\V1\BetaAnalyticsDataClient(['credentials' => $credentials]);

Be sure to check the constructor options for your clients to see which parameter (credentials or credentialsFetcher) it accepts

[velPL]

Thanks @bshaffer for clearing this out. It works perfectly with code snippet you provided

[erensertkaya]

this helped me to thank you
#7257