使用PHP API将评论或消息从我的网站发布到google plus wall

Question

我想使用PHP API将评论或消息从我的网站发布到google plus wall。

这是我的代码。

  include_once "templates/base.php";
    session_start();
    require_once realpath(dirname(__FILE__) . '/../src/Google/autoload.php');
    $client_id = '######';
    $client_secret = '####';
    $redirect_uri = 'http://www.example.com/idtoken.php';
    $client = new Google_Client();
    $client->setClientId($client_id);
    $client->setClientSecret($client_secret);
    $client->setRedirectUri($redirect_uri);
    $client->setScopes(
        array(
          "https://www.googleapis.com/auth/plus.me"
        )
    );

    if (isset($_REQUEST['logout'])) {
      unset($_SESSION['access_token']);
    }

    if (isset($_GET['code'])) {
      $client->authenticate($_GET['code']);
      $_SESSION['access_token'] = $client->getAccessToken();
    }

    if (isset($_SESSION['access_token']) && $_SESSION['access_token'])
    {
      $client->setAccessToken($_SESSION['access_token']);
    }
    else
    {
       $authUrl = $client->createAuthUrl();
    }

    if ($client->getAccessToken()) {
      $_SESSION['access_token'] = $client->getAccessToken();
      $token_data = $client->verifyIdToken()->getAttributes();
    }

     $access_token=json_decode($_SESSION['access_token'])->access_token;

    $url='https://www.googleapis.com/plusDomains/v1/people/102728965990039439412/activities';
    $ch = curl_init( $url );
    # Setup request to send json via POST.

    curl_setopt( $ch, CURLOPT_POSTFIELDS, $text );
    curl_setopt( $ch, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));
    curl_setopt( $ch, CURLOPT_HTTPHEADER, array('Authorization:OAuth'.$access_token));
    # Return response instead of printing.
    curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
    # Send request.
    $result = curl_exec($ch);
    curl_close($ch);
    # Print response.
    echo  "<pre>";
    print_r($result);
    echo "</pre>";
    exit;

以下是执行上述代码后得到的响应。

 {
     "error": {
      "errors": [
       {
        "domain": "global",
        "reason": "authError",
        "message": "Invalid Credentials",
        "locationType": "header",
        "location": "Authorization"
       }
      ],
      "code": 401,
      "message": "Invalid Credentials"
     }
    }

任何人都可以告诉我上面的代码有什么问题，或者我遗漏了什么？