如何使用Google API PHP客户端获取OAuth2访问令牌？

Question

我正在尝试获取OAuth访问令牌以将一些数据导入到融合表中.我正在尝试使用Google API PHP客户端.我已经为此创建了一个服务帐户,并且正在使用代码,主要来自serviceAccount示例:

function access_token()
{
    $client = new Google_Client();
    $client->setAuthClass ('Google_OAuth2');
    // ^ Don't know if this line is required,
    // ^ but it fails just as well without it.
    $client->setApplicationName ('Mysite.dom.ain');
    $client->setAssertionCredentials (new Google_AssertionCredentials
        (   'MANY-NUMBERS-LETTERS-DASHES@developer.gserviceaccount.com',
            array ('https://www.googleapis.com/auth/fusiontables'),
            file_get_contents ('path/to/my/privatekey.p12') ));
    $client->setClientId ('NUMBERS-LETTERS-DASHES.apps.googleusercontent.com');
    $client->authenticate();
    // ^ Also fails equally good with and without this line.
    return $client->getAccessToken();
}

一点调试输出显示$client->authenticate()返回true,但$client->getAcessToken()返回null.没有异常被抛出.我觉得我做的事情从根本上是错误的.如果是这样,请原谅我的愚蠢并指出我正确的方向.

Answer 1

您不需要authenticate()调用,但您需要调用refreshTokenWithAssertion()以刷新底层访问令牌.如果您使用客户端库来发出签名请求,那么如果底层访问令牌已过期,它将懒惰地为您进行此调用.

刷新access_token的API请求很昂贵,并且配额很低,因此您需要缓存access_token.

// Set your client id, service account name, and the path to your private key.
// For more information about obtaining these keys, visit:
// https://developers.google.com/console/help/#service_accounts
const CLIENT_ID = 'INSERT_YOUR_CLIENT_ID';
const SERVICE_ACCOUNT_NAME = 'INSERT_YOUR_SERVICE_ACCOUNT_NAME';

// Make sure you keep your key.p12 file in a secure location, and isn't
// readable by others.
const KEY_FILE = '/super/secret/path/to/key.p12';

$client = new Google_Client();
$client->setApplicationName("Google FusionTable Sample");

// Set your cached access token. Remember to store the token in a real database instead of $_SESSION.
session_start();
if (isset($_SESSION['token'])) {
 $client->setAccessToken($_SESSION['token']);
}

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

$client->setClientId(CLIENT_ID);

if ($client->getAuth()->isAccessTokenExpired()) {
  $client->getAuth()->refreshTokenWithAssertion();
}

// Get the json encoded access token.
$token = $client->getAccessToken();