Refinery CMS + Dragonfly + Amazon S3 + Amazon Cloudfront

gistfile1.txt

# config/environments/production.rb:
config.action_controller.asset_host = "http://cdn%d.example.com"

# config/initializers/refinery/images.rb:
config.dragonfly_url_format = "/images/:job/:basename.:ext"
if Rails.env.production?
  config.dragonfly_url_host = "http://cdn4.example.com"
end

# config/initializers/refinery/resources.rb:
config.dragonfly_url_format = "/resources/:job/:basename.:format"
if Rails.env.production?
  config.dragonfly_url_host = "http://cdn5.example.com"
end

----------------------

Configure 2 Amazon Cloudfront distributions:

1st pointing to S3 bucket and configured with these CNAMES: cdn0.example.com,
cdn1.example.com, cdn2.example.com and cdn3.example.com

2nd pointing to your site (in this example - example.com) because Dragonfly
generates thumbnails on the fly. This distribution is also configured with
these CNAMES: cdn4.example.com, cdn5.example.com

@cjbrew it generates an integer number

http://api.rubyonrails.org/classes/ActionView/Helpers/AssetUrlHelper.html