Curl give Result Fail

我在php服务器端工作。最初测试这段代码:

    $apiKey = "";

$registrationIDs = array( "" );

$message = "hello";

$url = 'https://android.googleapis.com/gcm/send';

$fields = array(
                'registration_ids'  => $registrationIDs,
                'data'              => array( "message" => $message ),
                );

$headers = array( 
                    'Authorization: key=' . $apiKey,
                    'Content-Type: application/json'
                );

$ch = curl_init();

$u=curl_setopt( $ch, CURLOPT_URL, $url );

$p=curl_setopt( $ch, CURLOPT_POST, true );
$f=curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
$h=curl_setopt( $ch, CURLOPT_HTTPHEADER, $headers);
$t=curl_setopt( $ch, CURLOPT_RETURNTRANSFER, true );
$c=curl_setopt($ch, CURLOPT_VERBOSE, true);
$j=curl_setopt( $ch, CURLOPT_POSTFIELDS, json_encode( $fields ) );

$result = curl_exec($ch);
 $responseInfo    = curl_getinfo($ch);
   $header_size    = curl_getinfo($ch, CURLINFO_HEADER_SIZE); 
   $responseHeader = substr($result , 0, $header_size);
   $responseBody   = substr($result , $header_size);
    echo 'Header: <br>'. $responseHeader;
    echo 'Body: <br>'. $responseBody;

curl_close($ch);
var_dump($ch);
var_dump($result);
but on :
var_dump($ch);
var_dump($result);

浏览器给出:

头:正文:类型为(Unknown)的资源(2)

bool (false)