/**
  * @brief showAttachment 防盗链显示、下载附件
  *
  * @param $params 参数
  *
  * @return void
  */
 public function showAttachment($params)
 {
     $meta = new MetaLibrary();
     $meta->setType(3);
     $meta->setMID($params['mid']);
     if (!($m = $meta->getMeta())) {
         Response::error(404);
         return;
     }
     $m = $m[0];
     // 判断 referer 防盗链
     $referer = Request::S('HTTP_REFERER', 'string');
     if ($referer) {
         $referer = parse_url($referer);
         $host = parse_url(OptionLibrary::get('domain'));
         if (LogX::getDomain($referer['host']) != LogX::getDomain($host['host'])) {
             Response::error(403);
             exit;
         }
     }
     $m['alias'] = LOGX_FILE . $m['alias'];
     // 通过判断getimagesize取出的图片信息是否存在类型标记和色彩位深来防止伪造。
     $isimage = false;
     if (stristr($m['description'], 'image')) {
         if (function_exists('getimagesize')) {
             $imginfo = @getimagesize($m['alias']);
             if (isset($imginfo[2]) && isset($imginfo['bits'])) {
                 $isimage = true;
             }
             unset($imginfo);
         } else {
             $isimage = true;
         }
     }
     // 附件读取形式,inline直接读取,attachment下载到本地
     $disposition = $isimage ? 'inline' : 'attachment';
     // 统计附件下载次数
     if ($disposition == 'attachment') {
         $meta->incReply($params['mid']);
     }
     $m['description'] = $m['description'] ? $m['description'] : 'application/octet-stream';
     if (is_readable($m['alias'])) {
         @ob_end_clean();
         if ($disposition == 'inline') {
             Response::setExpire(60 * 24 * 365);
         }
         header('content-Encoding: none');
         header('content-type: ' . $m['description']);
         header('content-Disposition: ' . $disposition . '; filename=' . urlencode($m['name']));
         header('content-Length: ' . abs(filesize($m['alias'])));
         $fp = @fopen($m['alias'], 'rb');
         @fpassthru($fp);
         @fclose($fp);
         exit;
     } else {
         Response::error(404);
     }
 }