Mobile Subdomains in Rails

mobile_site.rb

module MobileSite
  def self.included(base)
    base.class_eval do      
      # Uncomment for JQM Integration
      #rescue_from ActionView::MissingTemplate, :with => :view_unavailable
      
      before_filter :set_mobile_preferences
      before_filter :redirect_to_mobile_if_applicable
      before_filter :set_mobile_view_path

      private    

      def set_mobile_preferences
        if params[:mobile_site]
          cookies.delete(:prefer_full_site)
        elsif params[:full_site]
          cookies.permanent[:prefer_full_site] = 1
          redirect_to_full_site if mobile_request?
        end
      end      
      
      # Uncomment for Responsive CSS
      def set_mobile_view_path
         if mobile_request?          
          # Add Mobile view paths as overrides for mobile devices
          mobile_view_paths = ["#{Rails.root}/app/views_mobile"]
          Dir.glob("#{Rails.root}/vendor/plugins/*/app/views_mobile").map{ |f| mobile_view_paths << File.absolute_path(f) } 
          prepend_view_path(mobile_view_paths)
        end
      end
      
      # Uncomment for JQM Integration
      #def set_mobile_view_path
      #   if mobile_request?          
      #    # Clear the default view paths
      #    lookup_context.view_paths = [] 
      #
      #    # Add Mobile view paths
      #    mobile_view_paths = ["#{Rails.root}/app/views_mobile"]
      #    Dir.glob("#{Rails.root}/vendor/plugins/*/app/views_mobile").map{ |f| mobile_view_paths << File.absolute_path(f) } 
      #    prepend_view_path(mobile_view_paths)
      #  end
      #
      #  # Add Shared view paths for mobile & full site
      #  shared_view_paths = ["#{Rails.root}/app/views_shared"]
      #  Dir.glob("#{Rails.root}/vendor/plugins/*/app/views_shared").map{ |f| shared_view_paths << File.absolute_path(f) }
      #  prepend_view_path(shared_view_paths)
      #end
      
      # Uncomment for JQM Integration
      #def view_unavailable
      #  if mobile_request?
      #    render :template => 'error_pages/unavailable', :layout => 'application'
      #  end
      #end

      def redirect_to_full_site
        redirect_to request.protocol + request.host_with_port.gsub(/^m\./, '') +
                    request.fullpath and return
      end

      def redirect_to_mobile_if_applicable
        unless mobile_request? || cookies[:prefer_full_site] || !mobile_device?
          redirect_to request.protocol + "m." + request.host_with_port.gsub(/^www\./, '') +
                      request.fullpath and return
        end
      end

      def mobile_request?
        request.subdomains.first == 'm'
      end
      helper_method :mobile_request?

      def mobile_device?
        request.env["HTTP_USER_AGENT"] && request.env["HTTP_USER_AGENT"][/(iPhone|iPod|Android|Mobile|webOS)/]
      end
      helper_method :mobile_device?

    end
  end
end

class ActionController::Base
  include MobileSite 
end

# Based on http://erniemiller.org/2011/01/05/mobile-devices-and-rails-maintaining-your-sanity/