downloadresponse.php

См. документацию.

<?php
 
namespace Bitrix\Mail\Helper;

class DownloadResponse extends \Bitrix\Main\HttpResponse
{
    public function __construct(string $content, string $name = 'download_file', string $contentType = 'application/octet-stream')
    {
        parent::__construct();
        $this->setContent($content);
 
        $headers = new \Bitrix\Main\Web\HttpHeaders();
        $headers->add('Pragma', 'public');
        $headers->add('Expires', '0');
        $headers->add('Cache-Control', 'must-revalidate, post-check=0, pre-check=0');
        $headers->add('Content-Disposition', 'attachment; filename="' . $name . '";');
        $headers->add('Content-Transfer-Encoding', 'binary');
        $headers->add('Content-Length', strlen($content));
        $headers->add('Content-Type', $contentType);
 
        $this->setHeaders($headers);
    }
 
}