WP-API oAuth服务器到服务器流

如果尝试从另一台服务器（在本例中为同一台服务器上的另一个WP实例）连接到远程Wordpress WP-API，我对需要使用的流有点困惑。我正在使用PECL oAuth包，并且我从https://secure.php.net/manual/en/class.oauth.php.

这与wordpress保存挂钩类似，所以每次有人在SITE a上保存帖子时，它都会尝试将一些信息发送到SITE B:

add_action( 'save_post', 'CrossPollinate_Save',10,3);

CrossPollinate_Save内部是这样的：

$client_key =               "....";
$client_secret =            "....";
$request_token_endpoint =   "http://..../oauth1/request";
$authorize_endpoint =       "http://..../oauth1/authorize";
$access_endpoint =          "http://..../oauth1/access";
$callback =                 $_SERVER['REQUEST_URI'];
$request_token =            ""; //populated later
$request_token_secret =     ""; //populated later

//STEP 1
$oauth = new OAuth($client_key, $client_secret, OAUTH_SIG_METHOD_HMACSHA1, OAUTH_AUTH_TYPE_AUTHORIZATION);
$request_token_info = $oauth->getRequestToken($request_token_endpoint);
if(!empty($request_token_info)) {
    logToFile("Response from getRequestToken", $request_token_info);
} else {
    logToFile("Failed fetching request token: ", $oauth->getLastResponse());
}
$request_token = $request_token_info["oauth_token"];
$request_token_secret = $request_token_info["oauth_token_secret"];
logToFile("request_token is: ", $request_token);
logToFile("request_token_secret is: ", $request_token_secret);
//STEP 2
$oauth->setToken($request_token, $request_token_secret);
$access_token_info = $oauth->getAccessToken($authorize_endpoint."?oauth_callback=".$callback);
if(!empty($access_token_info)) {
    logToFile("Got access token! ", $access_token_info);
} else {
    logToFile("Failed fetching access token: " . $oauth->getLastResponse());
}

我从"步骤1"中得到了oauth_token和oauth_token_secret，太好了，这部分工作正常！当步骤2启动时，它最终返回一个包含登录页面标记的响应。我如何告诉oAuth跳过该步骤，只将访问令牌发送回重定向页面？