$add_header('Expires', $http_time($time()))
$add_header('Cache-Control', 'max-age=0, no-cache, no-store')
$add_header('Pragma', 'no-cache')
This example adds HTTP Expires, Cache-Control and Pragma headers to the response to
disallow for downstream caches from caching the page and the Expires and Pragma HTTP-EQUIV tags to
disallow browsers from caching the page.