nested_layouts

h1. NestedLayouts

This is a gem version for "radar/nested-layouts":http://github.com/radar/nested-layouts plugin.

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

h2. Usage

You can be installed as a gem from "Gemcutter":http://gemcutter.org. Add the following line to your @config/environment.rb@:

  config.gem "nested_layouts", :source => "http://gemcutter.org"

h2. 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'

    def hello
      render :text => 'Hello, world!'
    end
  end

app/views/layouts/inner.rhtml

  <% inside_layout 'outer' do -%>
    

      
Greetings
      <%= yield %>
    
  <% end -%>

app/views/layouts/outer.rhtml

  
  
    

      <%= yield %>
    
  
  

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

  
  
    

      

        
Greetings
        Hello, world!
      
    
  
  

h2. 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.

h2. 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 %>

h2. 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 %>

== Bugs & Feedback

Plugin originally by Ryan Bigg ([e-mail])

Home Page: "http://github.com/radar/nested-layouts":http://github.com/radar/nested-layouts