Methods
C
Instance Public methods
cache(name = {}, options = nil, &block)

This helper exposes a method for caching fragments of a view rather than an entire action or page. This technique is useful caching pieces like menus, lists of newstopics, static HTML fragments, and so on. This method takes a block that contains the content you wish to cache.

See ActionController::Caching::Fragments for usage instructions.

Examples

If you want to cache a navigation menu, you can do following: 

  <% cache do %>
    <%= render :partial => "menu" %>
  <% end %>

You can also cache static content: 

  <% cache do %>
     <p>Hello users!  Welcome to our website!</p>
  <% end %>

Static content with embedded ruby content can be cached as well: 

   <% cache do %>
     Topics:
     <%= render :partial => "topics", :collection => @topic_list %>
     <i>Topics listed alphabetically</i>
   <% end %>

Source: show | on GitHub 

    # File actionpack/lib/action_view/helpers/cache_helper.rb, line 34
34:       def cache(name = {}, options = nil, &block)
35:         if controller.perform_caching
36:           safe_concat(fragment_for(name, options, &block))
37:         else
38:           yield
39:         end
40: 
41:         nil
42:       end