A Nested Inheritable Layouts Helpers for Rails
Nestive adds powerful layout and view helpers to your Rails app. It's similar to the nested layout technique already documented in the Rails guides and found in many other nested layout plugins (a technique using
content_for and rendering the parent layout at the end of the child layout). There's a bunch of problems with this technique, including:
- you can only append content to the content buffer with
content_for(you can't prepend to content, you can't replace it)
- when combined with this nested layout technique,
content_foractually prepends new content to the buffer, because each parent layout is rendered after it's child
Nestive is better because it addresses these problems.
Just six methods (so far)
Declaring an area of content with
area helper is a lot like Rails' own
<%= yield :foo %>, and is used in layouts to define and render a chunk of content in your layout:
<%= area :sidebar %>
area will allow your parent layouts to add content to the area at the same time using either a String or a block:
<%= area :sidebar, "Some Content Here" %> <%= area :sidebar do %> Some Content Here <% end %>
It's important to note that this isn't default content, it is the content (unless a child changes it).
Appending content to an area with
The implementation details are quite different, but the
append helper works much like Rails' built-in
content_for. It will work with either a String or block, adding the new content onto the end of any content previously provided by parent layouts:
<%= extends :application do %> <% append :sidebar, "More content." %> <% append :sidebar do %> More content. <% end %> <% end %>
Prepending content to an area with
Exactly what you think it is. The reverse of
append (duh), adding the new content at the start of any content previously provided by parent layouts:
<%= extends :application do %> <%= prepend :sidebar, "Content." %> <%= prepend :sidebar do %> Content. <% end %> <% end %>
Replacing content with
You can also replace any content provided by parent layouts:
<%= extends :application do %> <%= replace :sidebar, "New content." %> <%= replace :sidebar do %> New content. <% end %> <% end %>
Removing content with
You can remove the content of the area:
<% purge :sidebar %>
... which is equal to:
<% replace :sidebar, nil %>
Extending a layout in a child layout (or view) with
Any layout (or view) can declare that it wants to inherit from and extend a parent layout, in this case we're extending
<%= extends :application do %> ... <% end %>
You can nest many levels deep:
<!DOCTYPE html> <html> <head> <%= area :head do %> <title><%= area :title, 'Nestive' %></title> <% end %> </head> <body> <%= yield %> </body> </html>
<%= extends :application do %> <div class="sidebar"><%= area(:sidebar) do %> here goes sidebar <% end %></div> <%= yield -%> <% end %>
The token blog example
Set-up a global layout defining some content areas.
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title><%= area :title, "JustinFrench.com" %></title> <meta name="description" content="<%= area :description, "This is my website." %>"> <meta name="keywords" content="<%= area :keywords, "justin, french, ruby, design" %>"> </head> <body> <div id="wrapper"> <div id="content"> <%= area :content do %> <p>Default content goes here.</p> <% end %> </div> <div id="sidebar"> <%= area :sidebar do %> <h2>About Me</h2> <p>...</p> <% end %> </div> </div> <%= yield %> </body> </html>
Next, we set-up a
blog layout that extends
application, replacing, appending & prepending content to the areas we defined earlier.
<%= extends :application do %> <% replace :title, "My Blog – " %> <% replace :description, "Justin French blogs here on Ruby, Rails, Design, Formtastic, etc" %> <% prepend :keywords, "blog, weblog, design links, ruby links, formtastic release notes, " %> <%= yield %> <% end %>
Now in our blog index view we can use
blog layout and fill in the areas with content specific to the index action.
<% replace :content do %> <h1>My Blog</h1> <%= render @articles %> <% end %> <% append :sidebar do %> <h2>Blog Roll</h2> <%= render @links %> <% end %>
We also need to instruct the
PostsController to use this
class PostsController < ApplicationController layout 'blog' end
Nestive works the same way
content_for does and has the same caching drawbacks. That means that nestive helpers are completely ignored when called from within cached block. You probably don't want to use fragment caching around dynamic nestive areas and have to be extra careful what and how you cach to avoid unpleasant surprises.
gem 'nestive', '~> 0.5'to your Gemfile
Nestive should work properly with any Rails 3 and 4. Since version 0.5 only Ruby 1.9.3 and newer are supported. For 1.8 compatibility use version 0.4.
Nestive doesn't monkey patch or fiddle with any default behaviors in Rails. Use it when you want to, don't when you don't.
You can help with...
- reporting issues
- fixing issues with pull requests
- performance testing