force download using ZF2 - zend-framework2

Question

I am trying to do force download using ZF2. Here is the snippet to my code
use Zend\Http\Request;
.....
public function downloadAction() {
$response = new Request();
$response->setHeaders(Request::fromString("Content-Type: application/octet-stream\r\nContent-Length: 9\r\nContent-Disposition: attachment; filename=\"ultimate_remedy_readme.txt\""));
}
now i am getting this error
/var/www/whowantsmymoney/vendor/zendframework/zendframework/library/Zend/Http/Request.php:88
Message:
A valid request line was not found in the provided string
Stack trace:
#0 /var/www/whowantsmymoney/module/Admin/src/Admin/Controller/LanguageController.php(93): Zend\Http\Request::fromString('Content-Type: a...')

Answer 1

This code should help you for a simple file download.
public function downloadAction() {
$fileName = 'somefile';
if(!is_file($fileName)) {
//do something
}
$fileContents = file_get_contents($fileName);
$response = $this->getResponse();
$response->setContent($fileContents);
$headers = $response->getHeaders();
$headers->clearHeaders()
->addHeaderLine('Content-Type', 'whatever your content type is')
->addHeaderLine('Content-Disposition', 'attachment; filename="' . $fileName . '"')
->addHeaderLine('Content-Length', strlen($fileContents));
return $this->response;
}
I imagine this code leaves a lot to be desired, but should work in simple cases, as was mine. I'm not sure how you might handle reading the file in chunks. Maybe somebody else could shed some light?
Edit - Sending streams
I've added this here for informational purposes. It is probably the better way to force downloads as it will use much less memory.
public function downloadAction() {
$fileName = 'somefile';
$response = new \Zend\Http\Response\Stream();
$response->setStream(fopen($fileName, 'r'));
$response->setStatusCode(200);
$headers = new \Zend\Http\Headers();
$headers->addHeaderLine('Content-Type', 'whatever your content type is')
->addHeaderLine('Content-Disposition', 'attachment; filename="' . $fileName . '"')
->addHeaderLine('Content-Length', filesize($fileName));
$response->setHeaders($headers);
return $response;

Answer 2

Thanks to #Aydin Hassan for response, but several important headers are missing in his answer. Be careful of that.
Full headers stack:
public function downloadAction() {
$file = 'path/to/file';
$response = new \Zend\Http\Response\Stream();
$response->setStream(fopen($file, 'r'));
$response->setStatusCode(200);
$response->setStreamName(basename($file));
$headers = new \Zend\Http\Headers();
$headers->addHeaders(array(
'Content-Disposition' => 'attachment; filename="' . basename($file) .'"',
'Content-Type' => 'application/octet-stream',
'Content-Length' => filesize($file),
'Expires' => '#0', // #0, because zf2 parses date as string to \DateTime() object
'Cache-Control' => 'must-revalidate',
'Pragma' => 'public'
));
$response->setHeaders($headers);
return $response;
}