public function export(Request $request)
 {
     $agent = new Agent();
     $builder = $agent->newQuery()->join('factory_agent', 'factory_agent.aid', '=', 'agents.id')->where('fid', '=', $this->factory->getKey());
     $page = $request->input('page') ?: 0;
     $pagesize = $request->input('pagesize') ?: config('site.pagesize.export', 1000);
     $total = $this->_getCount($request, $builder);
     if (empty($page)) {
         $this->_of = $request->input('of');
         $this->_table = $agent->getTable();
         $this->_total = $total;
         $this->_pagesize = $pagesize > $total ? $total : $pagesize;
         return $this->view('factory-backend.agent.export');
     }
     $data = $this->_getExport($request, $builder, null, 'agents.*');
     return $this->success('', FALSE, $data);
 }