application.html.erb

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<%= trail.to_html(response) %>

application_controller.rb

class ApplicationController < ActionController::Base
  before_filter :trail

  def self.trail(&block)
    # Controller-level trails become filters so they run inside the
    # request/response cycle, where internationalization etc works.
    before_filter {|controller| block.call(controller.send(:trail)) }
  end

  trail {|t| t << ['Home', '/'] }

protected

  def trail
    @breadcrumb_trail ||= BreadcrumbTrail.new
  end
  helper_method :trail

  class BreadcrumbTrail
    def initialize
      @crumbs = []
    end

    def <<(crumb)
      @crumbs << crumb
    end

    def append(crumbs)
      @crumbs += crumbs
    end

    def to_html(response)
      template = response.template
      @crumbs.map {|text, url| template.instance_eval {
        link_to_unless_current(h(text), url)
      } }.join(" &gt; ")
    end
  end

end

items_controller.rb

class ItemsController < ApplicationController

  trail {|t| t << ['Items', '/items'] }

  def show
    trail << ['Specific item from controller', '/items/123']
  end

end

show.html.erb

<%
  trail << ['Specific item from view', '/items/123']
  # Note that since layouts are rendered after their child template,
  # trails appended in a layout will currently come after those
  # appended in the child templates.
%>