breadcrumbs.rb

  # Plugin to manage breadcrumbs inside the app.
  module BreadCrumbs
    # Public: List of breadcrumbs encountered in this request. Add to this list
    # any breadcrumb as you match things in your Cuba app:
    #
    # Example
    #
    #   on root do
    #     breadcrumbs << "Home"
    #
    #     on "users" do
    #       breadcrumbs << "Users"
    #
    #       on get do
    #         # render the list
    #       end
    #
    #       on ":id" do |id|
    #         breadcrumbs << "Profile"
    #
    #         # etc
    #       end
    #     end
    #   end
    #
    #   This will automatically build an array with the following breadcrumbs:
    #
    #   [
    #     Crumb.new("Home", "/"),
    #     Crumb.new("Users", "/users"),
    #     Crumb.new("Profile", "/users/5")
    #   ]
    #
    #   In the view you can, then:
    #
    #   <% breadcrumbs.each do |crumb| %>
    #     <li class="<%= "active" if crumb.current? %>">
    #       <a href="<%= crumb.url %>"><%= crumb.name %></a>
    #     </li>
    #   <% end %>
    #
    # Returns an BreadCrumbs::List.
    def breadcrumbs
      env["app.breadcrumbs"] ||= Trail.new(env)
    end

    # The Trail is just an `env`-aware Array, with some convenient sugar for
    # adding items to it.
    class Trail < Array
      def initialize(env)
        @env = env
        super()
      end

      # Add a new crumb to this trail. This takes care of calculating the URL
      # from the path currently matched by Cuba, so all you need to provide is
      # the name.
      #
      # Returns self.
      def add(name, url = @env["SCRIPT_NAME"])
        push Crumb.new(name, url, @env)
      end
      alias_method :<<, :add

      # Crumbs are dumb values that know their #name, their #url, and whether
      # they match the current URL (according to the `env`, which they inherit
      # from their trail).
      class Crumb
        attr_reader :name, :url

        def initialize(name, url, env)
          @name = name
          @url = url
          @env = env
        end

        def current?
          url == (@env["SCRIPT_NAME"] + @env["PATH_INFO"])
        end
      end
    end
  end