Browsers do not cache response sent by MediaView - cakephp

Question

This is my controller code:
$this->viewClass = 'Media';
$params = array(
'id' => $filename '.gif',
'name' => $filename ,
'download' => false,
'extension' => 'gif',
'path' => $folderpath,
'cache' => '+30 days',
'modified' => '#' . filemtime($pathtofile),
);
$this->set($params);
and the response:
Debug is disabled in core.php. However, the browser (Firefox, Chrome) never caches the file and always download the whole thing. Is this because of the 200 OK response? How can I fix it?
EDIT
I probably should have added a sample of the actual request URL
http://localhost/mycontroller/mymediaaction/2345
I resolved the issue by setting the name attribute to the action parameter instead of the actual file name. I still appreciate an answer with some explanation of this behavior.

Answer 1

The following code snippet for a controller action would either serve a 304 response or the file. I think that the checkNotModified functionality should be done by the MediaView::render function internally, similar to the AssetDispatcher. But for the time being this snippet may be of help.
$modified = #filemtime(ROOT . $dir . $filename);
$this->response->modified($modified);
if ($this->response->checkNotModified($this->request))
{
$this->autoRender = false;
$this->response->send();
}
else
{
$this->viewClass = 'Media';
$params = array('id' => $filename,
'cache' => '+1 day',
'modified' => '#' . $modified, // Must be a string to work. See MediaView->render()
'path' => ROOT . $dir);
$this->set($params);
}
return;