module Roda::RodaPlugins::HostRouting::RequestMethods

def _get_host_routing_host

* The default value provided in the +hosts.default+ call
* The return value of the +hosts.default+ block, if given
* An exact match for a hostname given in +hosts.to+

following, in order:
Determine the host to use for the host routing support. Tries the 
def _get_host_routing_host
  host = self.host || ""
  roda_class.opts[:host_routing_hash][host] ||
    scope._host_routing_default(host) ||
    roda_class.opts[:host_routing_default_host]
end

def _host_routing_host

is only done once per request.
Cache the host to use in the host routing support, so the processing 
def _host_routing_host
  @_host_routing_host ||= _get_host_routing_host
end