To enable dynamic content to be cacheable with the proxy server,
in the administrative console, click Servers > Proxy servers > server_name >
HTTP proxy server settings > Proxy settings, and then select Cache
dynamic content. You enable cacheablity and invalidation of dynamic content
when you enable servlet caching on the application server, and specifying
the cache criteria in a cachespec.xml file that is associated
with that application. Invalidations are received by connecting to the cache
update URI that is associated with the invalidation servlet hosted on the
application server cluster. Dynamic content is content
that an application, that is hosted on an application server, generates. A
proxy server caches dynamic content only if the content is identified as edge
cacheable in the cachespec.xml file for the application.
All of the information that describes the cache, such as the ID to use for
the cache, dependency identifiers for invalidation, and expiration times,
is also defined in the cachespec.xml file. Proxy Server
uses the ESI protocol to obtain this information from the file.
See Configuring cacheable objects with the
cachespec.xml file for more information on how to set up a cachespec.xml file
for an application.
Cached dynamic content can be invalidated by events
in the application server. The ESI Invalidation Servlet, that is contained
in the DynacacheEsi.ear application, propagates these invalidation events
from the application server to the proxy server. The DynacacheEsi.ear is shipped
with WebSphere Application Server and must be deployed in the cluster with
the application that is generating the dynamic content for dynamic caching
at the proxy server to function properly.