For instance, when a customer purchases a vegetarian cookbook on an e-commerce site, the confirmation response could contain instructions for invalidating all catalog pages related to the book, its author and vegetables.
The ability to send invalidation message inline reduces the connection overhead associated with sending out-of-band invalidations and is a useful tool for ESI developers.
As described in Section 6.7, you create expiration policies and associate them with caching rules to refresh content from the origin server.
Response header invalidation is Oracle Web Cache functionality that enables an origin server to return a transactional response whose response body contains something other than HTML.
In addition to its greater flexibility in terms of response body content returned, response header invalidation requires less coding effort on the part of the Web applications since building an invalidation header is a fairly lightweight task.