Best way to combine fragment and object caching for memcached and Rails

Question

Lets say you have a fragment of the page which displays the most recent posts, and you expire it in 30 minutes. I\'m using Rails here.

<% cache(\"recent_posts         


        

Answer 1

What happens if the cache expires between the time you check for it in the controller and the time it's beeing checked in the view rendering?

I'd make a new method in the model:

  class Post
    def self.recent(count)
      find(:all, :limit=> count, :order=>"updated_at DESC")
    end
  end

then use that in the view:

<% cache("recent_posts", :expires_in => 30.minutes) do %>
  <% Post.recent(20).each do |post| %>
     ...
  <% end %>
<% end %>

For clarity, you could also consider moving the rendering of a recent post into its own partial:

<% cache("recent_posts", :expires_in => 30.minutes) do %>
  <%= render :partial => "recent_post", :collection => Post.recent(20) %>
<% end %>