search for: url_for_without_host

I am using subdomains in my application to control context. Therefor, during user registration, password reset, and other actions that require an email to be sent with a link to be clicked, I need to ensure that the subdomain appropriate for the user is used. It seems I need to be able to access request.host from within an ActionMailer model. But I am not clear how to do this. Any help would be