"Invalid Credentials" when accessing BigQuery through PHP API using service account

Question

I'm attempting to access Big Query through Google's php API using a service account.

<?php

require_once '../google-api-php-client/src/Google_Client.php';
require_once '../google-api-php-client/src/contrib/Google_BigqueryService.php';

define("CLIENT_ID", 'removed-removed.apps.googleusercontent.com');
define("SERVICE_ACCOUNT_NAME", 'removed-removed@developer.gserviceaccount.com');
define("KEY_FILE", '../../../key.p12');

define("PROJECT_ID", removed);

$client = new Google_Client();

$key = file_get_contents(KEY_FILE);

$client->setAssertionCredentials(new Google_AssertionCredentials(
                SERVICE_ACCOUNT_NAME,
                array('https://www.googleapis.com/auth/prediction'),
                $key)
);

$client->setClientId(CLIENT_ID);

// Instantiate a new BigQuery Client 
$service = new Google_BigqueryService($client);

try
{
    $service->tables->listTables(PROJECT_ID, "data");
} catch (Exception $e)
{
    echo $e->getMessage();
}

?>

Error calling GET https://www.googleapis.com/bigquery/v2/projects/removed/datasets/data/tables: (401) Invalid Credentials

Answer 1

Make sure you are using the correct OAuth scope - the scope in the code above is for the Google Prediction API. Use https://www.googleapis.com/auth/bigquery for full access to the BigQuery API. More about BigQuery API authorization here.

Example:

$client->setAssertionCredentials(new Google_AssertionCredentials(
                SERVICE_ACCOUNT_NAME,
                array('https://www.googleapis.com/auth/bigquery'),
                $key)
);