respond_to_mobile_requests.rb

module Mobylette
  module Controllers

    # Mobylette::Controllers::RespondToMobileRequests includes the respond_to_mobile_requests
    # to your ActionController::Base.
    #
    # The respond_to_mobile_requests method enables the controller mobile handling
    module RespondToMobileRequests
      extend ActiveSupport::Concern

      included do
        helper_method :is_mobile_request?
        helper_method :is_mobile_view?

        # List of mobile agents, from mobile_fu (https://github.com/brendanlim/mobile-fu)
        MOBILE_USER_AGENTS =  %w(
          alcatel
          amoi
          android
          astel
          audiovox
          blackberry
          cdm
          chtml
          docomo
          ericsson
          ipad
          iphone
          ipod
          j2me
          kddi
          midp
          minimo
          mmp
          mobi
          mobile
          mobileexplorer
          mot-
          motorola
          netfront
          nokia
          novarra
          palm
          pdxgw
          phone
          plucker
          pocket
          portable
          portalmmm
          sagem
          samsung
          sgh
          sie-
          softbank
          sprint
          symbian
          telit
          ucweb
          up.b
          upg1
          vodafone
          webos
          windows\ ce
          x240
          x320
          xiino
        )
      end

      module ClassMethods

        # This method enables the controller do handle mobile requests
        #
        # You must add this to every controller you want to respond differently to mobile devices,
        # or make it application wide calling it from the ApplicationController
        #
        # Options:
        # * fall_back: :html
        #     You may pass a fall_back option to the method, it will force the render
        #     to look for that other format, in case there is not a .mobile file for the view.
        #     By default, it will fall back to the format of the original request.
        #     If you don't want fall back at all, pass fall_back: false
        # * skip_xhr_requests: true/false
        #     By default this is set to true. When a xhr request enters in, it will skip the
        #     mobile verification. This will let your ajax calls to work as intended.
        #     You may disable this (actually you will have to) if you are using JQuery Mobile, or
        #     other js framework that uses ajax. To disable, set skip_xhr_requests: false
        def respond_to_mobile_requests(options = {})
          return if self.included_modules.include?(Mobylette::Controllers::RespondToMobileRequestsMethods)

          options.reverse_merge!({
            skip_xhr_requests: true
          })

          cattr_accessor :mobylette_options
          # works on 1.9, but not on 1.8
          #valid_options = [:fall_back, :skip_xhr_requests]
          #self.mobylette_options = options.reject {|option| !valid_options.include?(option)}
          options[:except] = Array(options[:except]).map {|ua| ua.to_s}
          self.mobylette_options = options

          self.send(:include, Mobylette::Controllers::RespondToMobileRequestsMethods)
        end

        def add_mobile_user_agent(agent)
          MOBILE_USER_AGENTS << agent
        end

        def remove_mobile_user_agent(agent)
          MOBILE_USER_AGENTS.delete agent
        end
      end

      private

      # :doc:
      # This helper returns exclusively if the request's  user_aget is from a mobile
      # device or not.
      def is_mobile_request?
        request.user_agent.to_s.downcase =~ Regexp.union(MOBILE_USER_AGENTS)
      end

      # :doc:
      # This helper returns exclusively if the current format is mobile or not
      def is_mobile_view?
        true if (request.format.to_s == "mobile") or (params[:format] == "mobile")
      end
    end

    # RespondToMobileRequestsMethods is included by respond_to_mobile_requests
    #
    # This will check if the request is from a mobile device and change
    # the request format to :mobile
    module RespondToMobileRequestsMethods
      extend ActiveSupport::Concern

      included do
        before_filter :handle_mobile
      end

      private

      # Returns true if this request should be treated as a mobile request
      def respond_as_mobile?
        processing_xhr_requests? and skip_mobile_param_not_present? and (force_mobile_by_session? or allow_mobile_response? or (params[:format] == 'mobile'))
      end

      def allow_mobile_response?
        user_agent_included? && is_mobile_request?
      end

      def user_agent_included?
        request.user_agent.to_s.downcase !~ Regexp.union(self.class.mobylette_options[:except])
      end

      # Returns true if the visitor has de force_mobile session
      def force_mobile_by_session?
        session[:mobylette_override] == :force_mobile
      end

      # Returns true when ?skip_mobile=true is not passed to the request
      def skip_mobile_param_not_present?
        params[:skip_mobile] != 'true'
      end

      # Returns true only if treating XHR requests (when skip_xhr_requests are set to false) or
      # or when this is a non xhr request
      def processing_xhr_requests?
        not self.mobylette_options[:skip_xhr_requests] && request.xhr?
      end

      # :doc:
      # Changes the request.form to :mobile, when the request is from
      # a mobile device
      def handle_mobile
        return if session[:mobylette_override] == :ignore_mobile
        if respond_as_mobile?

          original_format   = request.format.to_sym
          request.format    = :mobile
          if self.mobylette_options[:fall_back] != false
            request.formats << Mime::Type.new(self.mobylette_options[:fall_back] || original_format)
          end
        end
      end

    end
  end
end