在webman中使用xlswriter导出excel,如何返回给前端二进制流？

$file_name = time().'.xlsx';
$excel = new \Vtiful\Kernel\Excel(['path' => public_path().'/excel']);
$fileObject = $excel->constMemory($file_name);
$handle = $fileObject->getHandle();
$fileObject->data($excel_data);
$filePath = $fileObject->output();

    header("content-Type: application/vnd.openxmlformats-officedocument,spreadsheetml.sheet");
    header('Content-Disposition: attachment;filename="'.$file_name.'"'); 
    header('content-Length:'.filesize($filePath));
    header('Content-Transfer-Encoding: binary');
    header('Cache-Control: must-revalidate');
    header('Cache-Control: max-age=0');
    header('Pragma: public');
    if(ob_get_contents()){
        ob_clean();
    }  
    if(copy($filePath, 'php://output')=== false){
        throw new Exception($filePath ."地址出问题了");
    }else{
        return $this->json(200, '', ['list'=>$filePath, ]); 
    }
    flush();     
    以上显示二进制流打印在启动界面，怎么在浏览器中返回给前端呢？求专家指点。