How to configure Web Cache to cache remote portlet content

Some portlet developers have hard time to set up a correct environment to use invalidation based cache with portlets. The summary is often:
"it is working with the PDK Example provided in Oracle 9iAS but every time that I want to do it myself from Oracle JDeveloper or a stand alone OC4J the portlet is not cached !"

This is most of the case due to a bad understanding of the different components that are involved.

When we talk about invalidation based caching for Remote Portlet, we talk about a portlet that caches its content in a Web Cache that is between the Portal Midtier and the Web Provider Midtier. This is a first important point. That also means that you have to register your remote Web provider using a URL that points to this Web Cache.

PPE, Web Cache and Web Provider

 

So when you are developing a portlet within Oracle JDeveloper or deploying a portlet to an OC4J or an AS and you want to use invalidation based caching you have to put a Web Cache between the PPE and the Application Server that you are using. Let's take an example based on a execution of the Web Provider inside JDeveloper -embedded OC4J-, a URL like: http://dev-machine:port/application/providers.

So to cache the content of the portlets that are running in this OC4J you have to configure Web Cache using Web Cache Manager and:

1. create an Application Web Server that is the embedded OC4J
2. create a new Site Definition, this will create a new HTTP port, that you'll use to register your provider.
3. finally you have to create a "Site to server mapping", where you associate the OC4J to the new HTTP port.

After the bounce of Web Cache you can use the HTTP port on the Web Cache server to access your provider, and if the portlet is correctly configured -see this Oracle article -to support invalidation based caching; its content will be automatically cached.

Note: this tip is not limited to Portlet bu to any application that you want to develop and enhance using invalidation based caching.