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Nested Layouts

= NestedLayouts

Plugin allows to specify outer layouts for particular layout thus creating nested layouts.

Wrapping layout into another layout

Let’s assume you have controller which action ‘hello’ just was called. Controller was set up to use ‘inner’ layout:

app/controllers/hello_controller.rb
class HelloController < ApplicationController
  layout 'inner'
end
def hello
  render :text => 'Hello, world!'
end
app/views/layouts/inner.rhtml
<% inside_layout 'outer' do -%>
Greetings
<%= yield %>
<% end -%>
app/views/layouts/outer.rhtml
<html>
<body>
<%= yield %>
</body>
</html>

Result will look like this (formatted for better reading):

<html>
<body>
Greetings
Hello, world!
</body>
</html>
Concept

Concept of layout nesting here is based on the assumption that every inner layout is used only to customize it's outer layout and thus every inner layout is used only with one specific outer layout. With this in mind we can conclude that every layout must know it's outer layout and thus information about outer layout must be embeded directly into inner layout. Controller doesn't need to know about the whole stack of layouts, so you should just specify the most inner layout in it.

Passing data

You can pass data from inner layout to outer one, e.g.:

layouts/inner.rhtml
<% content_for 'menu' do -%>
About Us
Products
<% end -%>
<% inside_layout 'outer' do -%>
  <% @other_data_for_outer_layout = 'foo' -%>
  <%= yield %>
<% end -%>
layouts/outer.rhtml
<%= yield 'menu' %>
The data was: <%= @other_data_for_outer_layout %>
<%= yield %>
Inline layouts

Instead of using layout stored in file system, you can use inside_inline_layout to wrap template part into some template code passed as a string. It is usefull if you want to use layouts that are stored in DB:

Layout model
class Layout < ActiveRecord::Base
  # Has attributes 'name' and 'contents'
end
Helper
module ApplicationHelper
  def inside_db_layout(name, &block)
    layout = Layout.find_by_name(name)
    template = layout ? layout.contents : '<%= yield %>'
    inside_inline_layout(template, &block)
  end
end
View
<% inside_db_layout 'layout_from_db1' do %>
  Content
<% end %>
Download

Download it from http://rubyforge.org/projects/nested-layouts/ or via Rails plugin script: ./script/plugin install svn://rubyforge.org/var/svn/nested-layouts/trunk/nested_layouts

Bugs & Feedback

If you encounter any bugs or has some feature proposal, feel free to email it to maxim.kulkin@gmail.com.

NOTE: This description has been extracted from the Plugin README and so the formatting may need updating to make browser friendly