How can I strip a subdomain if it is "www" in a Rails 3.2 application? -

i have rails 3.2 application driven subdomains:

company1.myapp.com companyn.myapp.com 

some people trying this:

www.companyn.myapp.com 

which yields error. how can strip out leading subdomain if it's www?

i have in app controller:

def redirect_to_subdomain_page   subdomain = request.subdomain   subdomain = "xyz" if subdomain.blank? or subdomain=="www"   render "#{subdomain}_#{params[:action]}" end 

but if go www.companyn.myapp.com want redirect them companyn.myapp.com. want redirect them actual url changes.

request.subdomains should return array of subdomains like:

def redirect_to_subdomain_page   subdomains = request.subdomains   if subdomains.length <= 1     subdomain = subdomains.first     subdomain = "xyz" if subdomain.blank? or subdomain=="www"     render "#{subdomain}_#{params[:action]}"   else     redirect_to "http://companyn.myapp.com/#{request.fullpath}"   end end