Comment 0 for bug 505233

It will look like this:

GET(xml) {host}/ Application.index(format:'xml') using the route file. In the controller you can then access the host
variable if you wish.You can of course combine it with a regex or use
only a regex: {host}\.mydomain\..* Format means to render in xml.

If you decide to use annotations (provided by the router annotations
module) it will be something like (on you controller method):

@Get(value="{host}/", produces="xml")
public static void index(String host) {
....
}

It is still a proposal and can change over the time of course. If anyone has a better idea, syntax, etc I am open to all suggestion.