This is too complicated to not be centralized. If we need this anywhere else we need to do all of this again.
The code that interfaces with the cache shouldn't have to do more than

$cache->set('key', 'value');
$cache->set('key', 'value', 'ttl');
$cache->get('key');


It also most definitely should not have anything to do with the Response class.

Too general. TTL is content specific.