Caching - Cache-Control:
Caching - Cache-Control:
- Categories of Cache-Control: directives
- Restrictions on what is cachable; these may only be imposed by the origin server.
- Restrictions on what may be stored by a cache; these may be imposed by either the origin server or UA
- Modifications of the basic expiration mechanism; these may be imposed by either the origin server or the UA.
- Controls over cache revalidation and reload; these may only be imposed by a user agent.
- Control over transformation of entities.
- Extensions to the caching system.