protected function registerAfterListeners(Application $app)
{
// Add caching headers as appropriate, including sending an HTTP 304
// Not Modified if appropriate. Note: This does mean that we generate
// the whole response before deciding we don't need to send it, but
// since there is dependent data in the response (_embedded resources)
// we can't just use the primary resource's hash for the ETag.
$app->after(function (Request $request, Response $response) use($app) {
// In debug mode, disable all caching.
if ($app['debug']) {
return;
}
$cache_lifetime = $app['cache.lifetime'] ?: 0;
$response->setTtl($cache_lifetime)->setClientTtl($cache_lifetime);
$expires = new \DateTime("now +{$cache_lifetime} seconds", new \DateTimeZone('UTC'));
$response->setExpires($expires);
$etag = sha1($response->getContent());
$response->setEtag($etag);
if ($response->isNotModified($request)) {
$response->setNotModified();
}
}, 0);
}
