如何从PHP App Engine向GCM发送请求

Question

我正在使用PHP构建App Engine应用程序，但是当我尝试连接到GCM服务器时，它返回以下错误：
解析错误：语法错误，意外＆＃39; $ data＆＃39; （T_VARIABLE），期待＆＃39;）＆＃39;第6行
我正在使用此代码...

    $gcm_regid = "kjfadlfk;dkf;fpoekfldfk;";
    $url = "https://android.googleapis.com/gcm/send";

    $data = ['data' => 'this', 'registration_ids' => $gcm_regid];

    $data = http_build_query($data);
    $context = [
      'https' => [
        'method' => 'POST',
        'header' => "Content-Type: application/json\r\n" .
                    "Authorization: key=" . GOOGLE_API_KEY . "\r\n",
        'content' => $data
      ]
    ];
    $context = stream_context_create($context);
    $result = file_get_contents($url, false, $context);