gistfile1.rb

<div id='editor_switch'>
  <%
    if admin?
      (r = ::ActionController::TestRequest.new(request.env)).path = (request.request_uri.to_s.match(/\/admin(.*)\/edit/)[1] rescue root_url)
      public_route = ((c = ActionController::Routing::Routes.recognize(r)).present? and c != ApplicationController) ? r.path : root_url rescue root_url
    else
      if @page.present? and !@page.home?
        editor_route = edit_admin_page_url(@page)
      else
        editor_route = (request.request_uri.to_s == '/') ? admin_root_url : "/admin#{request.request_uri}/edit"
      end
    end
  -%>
  <%=
    link_to_if(admin?, "Switch to live view", public_route) do
      link_to "Switch to editor view", editor_route
    end
  -%>
</div>