PHP别名下载文件（TP5框架）

    public function index() {
        $id = (int)input('id');

        if(empty($id) || !is_numeric($id)){
            $this->error("参数错误");
        }

        $fileinfo = db('files')->where('id',$id)->find();
        if(!$fileinfo){
            $this->error("文件不存在！");
        }
        $file_url = './uploads/Download/'.$fileinfo['savepath'].$fileinfo['savename'];
        $out_filename = $fileinfo['name'];
        if(!file_exists($file_url)) {
            $this->error("文件不存在！");
        }else{
            header('Accept-Ranges: bytes');
            header('Accept-Length: ' . filesize( $file_url ));
            header('Content-Transfer-Encoding: binary');
            header('Content-type: application/octet-stream');
            header('Content-Disposition: attachment; filename=' . $out_filename);
            header('Content-Type: application/octet-stream; name=' . $out_filename);
            if(is_file($file_url) && is_readable($file_url)){
                $file = fopen($file_url, "r");
                echo fread($file, filesize($file_url));
                fclose($file);
            }
        }
    }