Cache whole previews list fragments

app/models/asciicast.rb

@@ -23,6 +23,11 @@ class Asciicast < ActiveRecord::Base
     update_all(:user_id => user.id, :user_token => nil)
   end
 
+  def self.cache_key
+    timestamps = scoped.select(:updated_at).map { |o| o.updated_at.to_i }
+    Digest::MD5.hexdigest timestamps.join('/')
+  end
+
   def meta=(file)
     data = JSON.parse(file.tempfile.read)
 

app/views/asciicasts/_previews.html.erb

@@ -1,3 +1,5 @@
 <div class="presentations">
-  <%= render :partial => 'asciicasts/preview', :collection => @asciicasts %>
+  <% cache @asciicasts do -%>
+    <%= render :partial => 'asciicasts/preview', :collection => @asciicasts %>
+  <% end -%>
 </div>