“403 Forbidden"响应谷歌Android应用程序内购买API与服务帐户

无法使用本地Google PHP客户端使Android In App purchase API与服务帐户凭据一起工作。

我从Google PHP客户端包(Google 'examples'service-account.php)中获取样例脚本，它提供了所有必需的证书，它在"图书"服务中工作得很好，但在"应用程序购买中的Android"中却不行。

下面的代码运行正常:

$client_id = '{SERVICE_CLIENT_ID}';
$service_account_name = '{SERVICE_ACCOUNT_NAME}';
$key_file_location = '{KEY_PATH}';
$client = new Google_Client();
$client->setApplicationName("Client_Library_Examples");
$service = new Google_Service_Books($client);
$scopes = array('https://www.googleapis.com/auth/books');
$key = file_get_contents($key_file_location);
$cred = new Google_Auth_AssertionCredentials($service_account_name, $scopes, $key);
$client->setAssertionCredentials($cred);
if($client->getAuth()->isAccessTokenExpired()) {
    $client->getAuth()->refreshTokenWithAssertion($cred);
}
echo '<pre>'; $results = $service->volumes->listVolumes('Henry David Thoreau', array('filter' => 'free-ebooks')); print_r($results); echo '</pre>';

下面的代码以"403 Forbidden"作为Google的响应结束:

$client_id = '{SERVICE_CLIENT_ID}';
$service_account_name = '{SERVICE_ACCOUNT_NAME}';
$key_file_location = '{KEY_PATH}';
$client = new Google_Client();
$client->setApplicationName("Client_Library_Examples");
$service = new Google_Service_AndroidPublisher($client);
$scopes = array('https://www.googleapis.com/auth/androidpublisher');
$key = file_get_contents($key_file_location);
$cred = new Google_Auth_AssertionCredentials($service_account_name, $scopes, $key);
$client->setAssertionCredentials($cred);
if($client->getAuth()->isAccessTokenExpired()) {
    $client->getAuth()->refreshTokenWithAssertion($cred);
}
echo '<pre>'; $results = $service->inapppurchases->get('{PACKAGE}', '{PRODUCT}', '{TOKEN}'); print_r($results); echo '</pre>';

我还对Web帐户凭证进行了测试(当访问令牌由Google在"redirect"之后给出的特殊"代码"生成时)。结果是一样的——403 Forbidden.

谁能给任何线索为什么Android API不工作，它的预期?