/**
* Prepares the response for caching by the decorator. Sets up headers and renders the response
* body due to some caching methods not serialising [Kohana_View] correctly. The `_prepare_response()`
* method performs the following.
*
* 1. Set correct headers to the Response object, formatting `Cache-Control` correctly
* 2. Creates an `Expires:` header if required
* 3. Renders the [Kohana_Reponse]::`$body`
*
* @param Kohana_Response response
* @return Kohana_Response
*/
protected function _prepare_response(Kohana_Response $response)
{
// Get the cache control headers
$cache_control = Request_Cache::parse_cache_control($response->headers);
// Set the lifetime of the cache from the header
$this->_lifetime = (int) $cache_control['max-age'];
// Get time now
$time = time();
// If the expires header is not set
if (!isset($response->headers['Expires'])) {
// Calculate expires header (DateTime would probably be better here - SdF)
$expires = gmdate('D, d M Y H:i:s T', $time + $cache_control['max-age']);
}
// Tell caches to check their validation
$cache_control['must-revalidate'] = NULL;
// Replace the headers with those that are not set
$response->headers += array('Cache-Control' => Request_Cache::create_cache_control($cache_control), 'Expires' => $expires, 'Last-Modified' => gmdate('D, d M Y H:i:s T', $time), 'Content-Length' => strlen((string) $response->body));
// Render the body (some caches have trouble serializing)
$response->body = (string) $response->body;
// return
return $response;
}
/**
* Validates a cached response to check it is still fresh and available
* to the client. All validation is based on the `max-age` Cache-Control
* header.
*
* // Get a response from the cache
* $response = Request::$cache->get('foo');
*
* // Test the response
* if (Request_Cache::validate_get($response))
* {
* // Return the valid cached response
* return $response;
* }
*
* @param Kohana_Response resposne
* @return boolean
*/
public static function validate_get(Kohana_Response $response)
{
// Get the Cache-Control Header
$cache_control = Request_Cache::parse_cache_control((array) $response->headers);
// If the response has expired
if ($cache_control['max-age'] + time() < time()) {
// Remove this entry
Request_Cache::delete($key);
// return false
return FALSE;
}
// Return true
return TRUE;
}
