HTTP::Server::Simple::Authen is an HTTP::Server::Simple plugin to allow
HTTP authentication. Authentication scheme is pluggable and you can use
whatever Authentication protocol that Authen::Simple supports.

You can use 'authenticate' method whatever you want to authenticate the
request. The method returns '$username' taken from the request if the
authentication is successful, and 'undef' otherwise. The code in the
/SYNOPSIS manpage requires authentication for all the requests and behaves
just the same as Apache's 'Require valid-user'.

The following code will explain more about conditioning.