Companion

Cache control request directives that uses the cache only, even if the cached response is stale. If the response isn't available in the cache or requires server validation, the call will fail with a 504 Unsatisfiable Request.

Cache control request directives that require network validation of responses. Note that such requests may be assisted by the cache via conditional GET requests.

Returns the cache directives of headers. This honors both Cache-Control and Pragma headers if they are present.