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:https://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:

expire_fragment /.*search.*/

Where the regular expression matches the fragment cache path.