问数据万象添加盲水印的时候报错怎么解决？

<?php
    namespace App\Http\Controllers;

    use App\Extensions\Tencent\Signature;

    class IndexController extends Controller
    {
        protected $text = 'http://watermark-1256115051.picgz.myqcloud.com/tengxunyun.png';

        protected $type = 2;

        protected $host = 'watermark-1256115051.pic.ap-guangzhou.myqcloud.com';

        protected $fileid = 'water.jpg';

        protected $key = '123.jpg';

        protected $authorization;

        protected $guzzleHttpClient;

        protected $filePath;

        protected $fileSource;

        public function __construct()
        {
            $this->guzzleHttpClient = new \GuzzleHttp\Client([
                'base_uri' => 'http://pic.ap-guangzhou.myqcloud.com',
                'timeout'  => 30,
            ]);
            $signature = new Signature(env('TENCENT_SECRETID'), env('TENCENT_SECRETKEY'));
            $this->authorization = $signature->getAuthorization('PUT', $this->key);
            $this->filePath = public_path('upload/images/20190511/abc.jpg');
            $this->fileSource = fopen($this->filePath, 'rb');
        }

        public function index()
        {
            $picOperations = array(
                'is_pic_info' => 1,
                'rules' => [
                    [
                        'fileid' => $this->fileid,
                        'rule' => 'watermark/3/type/2/image/'.base64_encode($this->text)
                    ]
                ]
            );
            $result = $this->guzzleHttpClient->request('PUT', '/'.$this->key, [
                'headers'=>[
                    'Authorization' => $this->authorization,
                    'Host' => $this->host,
                    'Content-Length' => filesize($this->filePath),
                    'Pic-Operations' => json_encode($picOperations)
                ],
                'body' => $this->fileSource
            ]);
            dd($result->getBody()->getContents());
        }

        public function urlsafeB64encode($string) {
            return base64_encode($string);
        }
    }
?>