Add Varnish cache headers to controller actions. Automatically purge instances and models on after_create, after_update and after_destroy callbacks.

1. Add this line to your application's Gemfile:

gem 'varnish_rails'

2. Run

$ bundle install

3. Install VarnishRails

$ rails generate varnish_rails:install

1. Complete the config/initializers/varnish_rails.rb file.

1. Add before_action :set_varnish_headers(max_age_in_seconds) in controllers that you wanna cache.

2. Add calls to add_to_varnish_xkey_header(my_collection_or_item) in the cached controller actions to automatically generate the Varnish xkeys.

3. For models that don't have to be purged automatically, add the following line is_updated_via_import to the model. You can then call MyModel::purge_cache_by_varnish_class_name to purge all cached pages that use this model.

4. You can use Varnish ESI in your layout:

<% if @varnish_headers_are_set %>
  <esi:include src="/includes/header"/>
  <esi:remove>
    <%= render "/shared/header" %>
  </esi:remove>
<% else %>
  <%= render "/shared/header" %>
<% end %>

• Mario Bouchard

The gem is available as open source under the terms of the MIT License.