The onCore* events are fired at some pre-defined points during the
handling of a request. At this is more important than the fact
that you can change things from the event.
The only missing part is ContainerAwareEventManager::addEventSubscriberService(),
because I'm not sure how to find out the class name of a service in the DIC.
Also, inline documentation of this code needs to be finished once it is accepted.
According to ResponseHeaderBag::computeCacheControlValue(), a response with an ETag but no explicit Cache-Control header should have a sensible Cache-Control of "private, must-revalidate" set. According to Response::isCacheable(), a response that includes a private Cache-Controls is not considered cacheable. Therefore, in order for this test response to be cacheable and stored, it requires an explicit Cache-Control of public.
Rules are :
- If one of the ESI has validation cache strategy, the whole page will be
forced to validate.
- In none of the ESI has validation, the response will feature a Cache-Control
directive with s-maxage value equals to the smallest TTL of ESIs.
