I know that's it's technically possible to create a path that allows any character in it by using constraints. However, I have found that it's impossible to create a route that has a dot at the base of the path, e.g.
http://localhost:5000/.well-known/acme-challenge/
This is the route I've been using:
get ':my_root/acme-challenge/:id', to: 'pages#letsencrypt', constraints: {my_root: /.+/}
Anyone have any ideas?