symfony2重定向到流文件

Hi guys I have a little question in symfony2.

Can you tell me how to redirect in controller to open (stream) a file in asset folder Not to force to download

for example : I have a file in root/web/bundles/ace/file.pdf

I used this code, but this failed to open /stream the file. This code force browser to download

        $path = $this->get('kernel')->getRootDir().DIRECTORY_SEPARATOR."..".DIRECTORY_SEPARATOR."web".DIRECTORY_SEPARATOR."bundles".DIRECTORY_SEPARATOR.
            "bsibkpm".DIRECTORY_SEPARATOR."download".DIRECTORY_SEPARATOR . $fileName;
    //echo $path;die();
    $content = file_get_contents($path);

    $response = new Response();

    $response->headers->set('Content-Type', 'application/pdf');
    $response->headers->set('Content-Disposition', 'attachment;filename="'.$fileName);
    $response->sendHeaders();
    $response->setContent($content);
    return $response;``

Many thanks for your help before

Hendrawan