这适用于使用 CURL
function sendGCM($message, $id) {
    $url = 'https://fcm.googleapis.com/fcm/send';
    $fields = array (
            'registration_ids' => array (
                    $id
            ),
            'data' => array (
                    "message" => $message
            )
    );
    $fields = json_encode ( $fields );
    $headers = array (
            'Authorization: key=' . "YOUR_KEY_HERE",
            'Content-Type: application/json'
    );
    $ch = curl_init ();
    curl_setopt ( $ch, CURLOPT_URL, $url );
    curl_setopt ( $ch, CURLOPT_POST, true );
    curl_setopt ( $ch, CURLOPT_HTTPHEADER, $headers );
    curl_setopt ( $ch, CURLOPT_RETURNTRANSFER, true );
    curl_setopt ( $ch, CURLOPT_POSTFIELDS, $fields );
    $result = curl_exec ( $ch );
    echo $result;
    curl_close ( $ch );
}
?>
$message是您要发送到设备的消息
$id是设备注册令牌
YOUR_KEY_HERE是您的服务器 API 密钥(或旧版服务器 API 密钥)