Besides obvious optimizations like using APC, you probably have some caching strategy for your PHP projects. Most frameworks nowadays provide tools to cache pages, and interfaces to software like Memcache. But did you know that caching is a large part of the HTTP specification (RFC 2616)? In the first part of this session, I will show how you can take advantage of HTTP caching and how to leverage gateway caches.
Akamaï wrote the ESI language specifications (Edge Side Includes) in 2001 to provide a means to build pages with different HTTP resources. It brings a lot of flexibility to the table. Varnish, one of the most popular reverse proxy, support ESI out of the box. The second part of this session will show how you can use ESI in your next PHP project.