def http_cache_forever(public: false)
      expires_in 100.years, public: public

      yield if stale?(etag: request.fullpath,
                      last_modified: Time.new(2011, 1, 1).utc,
                      public: public)
    end
def http_cache_forever(public: false)
      expires_in 100.years, public: public

      yield if stale?(etag: request.fullpath,
                      last_modified: Time.new(2011, 1, 1).utc,
                      public: public)
    end
Cache or yield the block. The cache is supposed to never expire.

 You can use this method when you have an HTTP response that never changes,
 and the browser and proxies should cache it indefinitely.

 * +public+: By default, HTTP responses are private, cached only on the
   user's web browser. To allow proxies to cache the response, set +true+ to
   indicate that they can serve the cached response to all users.