The dalli-store-extensions plugin for Rails 3 adds support for match-based deletes while using the dalli storage engine.
In your Gemfile, make sure you have dalli and this gem:
gem 'dalli' gem 'dalli-store-extensions', :git => "git://github.com/defconomicron/dalli-store-extensions.git"
In your config/environments/X.rb, where X is the name of the environment where you'd like to enable caching, make sure you are using the dalli storage engine:
config.cache_store = :dalli_store
You now use standard rails caching mechanisms. To expire a fragment:
Where the regular expression matches the fragment cache path.