class HTTP::Cache

def get_response(req, options, request_performer)
  cached_resp = cache_lookup(req)
  return cached_resp if cached_resp && !cached_resp.stale?
  # cache miss
  logger.debug { "Cache miss for <#{req.uri}>, making request" }
  actual_req = if cached_resp
                 req.conditional_on_changes_to(cached_resp)
               else
                 req
               end
  actual_resp = make_request(actual_req, options, request_performer)
  handle_response(cached_resp, actual_resp, req)
end