That allows projects that only use HttpFoundation and not HttpKernel to be able to
enforce the HTTP specification "rules".
$request = Request::createFromGlobals();
$response = new Response();
// do whatever you want with the Respons
// enforce HTTP spec
$response->prepare($request);
$response->send();
Within Symfony2, the prepare method is automatically called by the ResponseListener.
The PHP native cache limiter feature has been disabled as this is now managed
by the HeaderBag class directly instead (see below.)
The HeaderBag class uses the following rules to define a sensible and
convervative default value for the Response 'Cache-Control' header:
* If no cache header is defined ('Cache-Control', 'ETag', 'Last-Modified',
and 'Expires'), 'Cache-Control' is set to 'no-cache';
* If 'Cache-Control' is empty, its value is set to "private, max-age=0,
must-revalidate";
* But if at least one 'Cache-Control' directive is set, and no 'public' or
'private' directives have been explicitely added, Symfony2 adds the
'private' directive automatically (except when 's-maxage' is set.)
So, remember to explicitly add the 'public' directive to 'Cache-Control' when
you want shared caches to store your application resources:
// The Response is private by default
$response->setEtag($etag);
$response->setLastModified($date);
$response->setMaxAge(10);
// Change the Response to be public
$response->setPublic();
// Set cache settings in one call
$response->setCache(array(
'etag' => $etag,
'last_modified' => $date,
'max_age' => 10,
'public' => true,
));
