And for this specific request, it fdqn is looked up only for "logging" to sys.stderr. Either removing the fqdn call or just caching per connection it as the patch does is both fine. I doubt if someone is relying this logging anywhere in the code. This is useful only when BaseHTTPServer is started in the command like as a standalone HTTP server.

What shall we do for this? remove the fqdn or cache it once and use it. Either is fine. And there is not testing code present (or required too - as this is a cli invocation scenario).