Multiple Level Nested Layout in Rails 3 - ruby-on-rails

Question

I have an application with a global application layout file application.html.haml. I then have multiple "controller stacks": for our main site, our admin portal, and our business site. For each of these, controllers are within a module and all inherit from the same BaseController. Each stack has it's own layout file. Within the stack, some controllers have layout files as well.
I would like all views (unless otherwise specified) to render inside multiple levels of nested layouts : application, "stack", "controller".
For example, for the Site::BlogController#show action, I'd like rails to render:
/site/blog/show.html.haml inside /layouts/site/blog.html.haml inside /layouts/site.html.haml inside /layouts/application.html.haml
I am having difficulty understanding how to insert /layouts/site.html.haml into the stack. It appears as though automatically, rails will render the action inside the controller layout inside the application layout, however, I can't see how to "insert" layouts into the render stack.
Any help is greatly appreciated, however, I have read all the rails guides to no avail, so a link to http://guides.rubyonrails.org/layouts_and_rendering.html#using-nested-layouts will not really be helpful.

Answer 1

I reread the link i posted ( http://guides.rubyonrails.org/layouts_and_rendering.html#using-nested-layouts ) and realized I missed a key detail.
<%= render :file => 'layouts/application' %>
so, in Site::BaseController I have a call to layout 'site' and in /layouts/site.html.haml I have
= content_for :footer do
-#Content for footer
= render :file => 'layouts/application'
Then in Site::BlogController which extends Site::BaseController I have layout 'site/blog' and in /layouts/site/blog.html.haml I have
=content_for :header do
%h1 HELLO WORLD!
= render :file => 'layouts/site'
This then renders the layouts nested as described in the question. Sorry for missing this in my question. I should've read closer.

Answer 2

if you create a helper like this:
# renders a given haml block inside a layout
def inside_layout(layout = 'application', &block)
render :inline => capture_haml(&block), :layout => "layouts/#{layout}"
end
then you can define sublayout like this:
= inside_layout do
# nested layout html here
= yield
these layouts can be used like normal layouts.
more: http://www.requests.ch/blog/2013/10/30/combine-restful-rails-with-nested-layouts/

Answer 3

I've done similar, but only used 1 level of sublayouts. Can easily be tweaked to allow multiple levels.
In controllers/application_controller.rb:
def sub_layout
nil
end
In controller (for example blog_controller.rb):
def sub_layout
"blog"
end
In layouts/application.html.erb rather than <%=yield%>:
<%= controller.sub_layout ? (render :partial => "/layouts/#{controller.sub_layout}") : yield %>
Make a partial layouts/_blog.html.erb:
...code
<%=yield%>
...code
Repeat for other controller & sub layouts.
EDIT:
If you need to do this on a per-action basis:
def sub_layout
{
'index' => 'blog',
'new' => 'other_sub_layout',
'edit' => 'asdf'
}[action_name]
end

Answer 4

I guess the simplest way to do it is by adding this line of code in the parent of a nested layout:
((render "layouts/#{controller_name}" rescue nil)|| yield )
you could add as many nested layouts as you want by only changing the path directory of the next layout to be rendered.
note: make sure your nested layout is named _layoutname.whatever and that your nested layout has a yield inside

Answer 5

You can create a partial with a yield in it.
_my_sub_layout.html.erb:
<h3>I'm a sub layout and here's my content:</h3>
<%= yield %>
In some other view or even in your main layout application.html.erb render the partial as a layout:
<%= render layout: 'my_sub_layout' do %>
<p>I'm the sub layout's content</p>
<% end %>