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rails--rails/actionpack/lib/action_view/helpers/cache_helper.rb

60 lines
1.9 KiB
Ruby

module ActionView
# = Action View Cache Helper
module Helpers
module CacheHelper
# 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 %>
def cache(name = {}, options = nil, &block)
if controller.perform_caching
safe_concat(fragment_for(name, options, &block))
else
yield
end
nil
end
private
# TODO: Create an object that has caching read/write on it
def fragment_for(name = {}, options = nil, &block) #:nodoc:
if fragment = controller.read_fragment(name, options)
fragment
else
# VIEW TODO: Make #capture usable outside of ERB
# This dance is needed because Builder can't use capture
pos = output_buffer.length
yield
fragment = output_buffer.slice!(pos..-1)
controller.write_fragment(name, fragment, options)
end
end
end
end
end