Content Cache

eZ Platform uses Symfony HttpCache to = manage content "view" cache with an expiration model. In addition it is extended = (using FOSHttpCache) to add several advanced features. For content com= ing from the CMS the following is taken advantage of out of the box:

To be able to always keep cache up to date, cache is made "content-awar= e" to allow updates to content to trigger cache invalidation.
- Uses a custom X-Location-Id header, which both Symfony and= Varnish Proxy are able to invalidate cache on (for details see cache purge document.)
To be able to also cache requests by logged-in users, cache is made "
Context-Aware."
- Uses a custom vary header X-User-Hash to allow pages to va= r by user rights (so not per unique user, that is better se= rved by browser cache.)

Cache and Expiration C= onfiguration

ezplatform.yml

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ezpublish:
    system:
        my_siteaccess:
            content:
                view_cache: true      # Activates HttpCache for content
                ttl_cache: true       # Activates expiration based HttpCach=
e for content (very fast)
                default_ttl: 60       # Number of seconds an Http response =
is valid in cache (if ttl_cache is true)

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Making your = controller response content-aware

Sometimes you need your controller's cache to be invalidated at the same= time as specific content changes (i.e. ESI sub-requests with render twig helper,= for a menu for instance). To be able to do that, you just need to add X-Location-Id header to the response object:

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use Symfony\Component\HttpFoundation\Response;
 
// Inside a controller action
// "Connects" the response to location #123 and sets a max age (TTL) of 1 h=
our.
$response =3D new Response();
$response->headers->set('X-Location-Id', 123);
$response->setSharedMaxAge(3600);

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Making your = controller response context-aware

If the content you're rendering depends on a user's permissions, then yo= u should make the response Context-aware:

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use Symfony\Component\HttpFoundation\Response;
 
// Inside a controller action
// Tells proxy configured to support this header to take the rights of a us=
er (user hash) into account for the cache
$response =3D new Response();
$response->setVary('X-User-Hash');

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