An administrator can enable caching for both static and
dynamic content in the proxy server.
About this task
Complete the following steps to configure a proxy server
such that it can cache static and dynamic content.
Procedure
- Configure the object cache instance for size, disk offload
location, and other such capabilities, in the administrative console.
Click proxy_server_name. Repeat these
steps on any nodes that have a proxy server.
- Select the proxy cache store instance and enable configuration
attributes such as cache size, disk offload, and cache replication. For disk offload, it is recommended that the location be set
to a dedicated disk partition.
- Enable caching at the proxy server, in the administrative
console. Click proxy_server_name page in the administrative console.
- Select Enable caching and choose a cache instance
from the drop-down box.
- To enable dynamic content to be cacheable with the
proxy server, in the administrative console, click proxy_server_name, 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.
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 the product, 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.
- Static caching is enabled by default when caching is
enabled for the proxy server. Static content is
web content that is public and accompanied by HTTP response headers,
such as EXPIRES and LAST_MODIFIED_TIME, that describe how long the
response can be cached. The proxy server uses the HTTP 1.1 RFC (2616),
which specifies how content should be treated and includes capabilities
such as VARY header support for caching variants of the same resource
Uniform Resource Identifier (URI).