One of the ways to speed up an application is to store chunks of generated HTML code, or even full pages, for future requests. This technique is known as caching, and it can be managed on the server side and on the client side.
Symfony offers a flexible server-caching system. It allows saving the full response, the result of an action, a partial, or a template fragment into a file, through a very intuitive setup based on YAML files. When the underlying data changes, you can easily clear selective parts of the cache with the command line or special action methods. Symfony also provides an easy way to control the client-side cache through HTTP 1.1 headers. This chapter deals with all these subjects, and gives you a few tips on monitoring the improvements that caching can bring to your applications.