text: exports.ajaxDownload = function(download_param) {
    // 此值需要与jquery ajax download 插件设置的一致
    const input_param = download_param || 'download_param';
  
    return function(req, res, next) {
      let param = req.body[input_param];
      let params = JSON.parse(param);
      req.body = params;
  
      // 设置jquery ajax download插件需要的cookie
      res.cookie('fileDownload', 'true', {httpOnly: false});
      return next();
    };
  };
  