gistfile1.rb

CONTENT_TYPES = {:html => 'text/html', :css => 'text/css', :js  => 'application/javascript'}

before do
  request_uri = case request.env['REQUEST_URI']
    when /\.css$/ : :css
    when /\.js$/  : :js
    else          :html
  end
  content_type CONTENT_TYPES[request_uri], :charset => 'utf-8'
end