code: public function delBatch($files)
      {
          $url = $this->QINIU_RS_HOST . '/batch';
          $ops = [];
          foreach ($files as $file) {
              $ops[] = "/delete/" . self::qiniuEncode("{$this->bucket}:{$file}");
          }
          $params = 'op=' . implode('&op=', $ops);
          $url .= '?' . $params;
          trace($url);
          $accessToken = $this->accessToken($url);
          $response    = $this->request($url, 'POST', ['Authorization' => "QBox $accessToken"]);
          return $response;
      }
docs: 批量删除文件