Invalidating individual keys from rack-cache?

Question

Let's say a path on my rails app got stuck in rack cache. Is there a way to say: "/games/zelda" should be removed/invalidated from rack-cache?

Answer 1

Assumtions

1. Your rails app is named MyApp
2. the complete url you wish to purge is http://www.myapp.com/games/zelda

Step 1 obtain a normalized key

mock_request = Rack::MockRequest.env_for('/games/zelda', {"SERVER_NAME"=>"www.myapp.com"})
key = Rack::Cache::Key.call(Rack::Cache::Request.new(mock_request))

Step 2 retrieve storage objects

metastore_uri = MyApp::Application.config.action_dispatch.rack_cache[:metastore]
entitystore_uri = MyApp::Application.config.action_dispatch.rack_cache[:entitystore]

metastore = Rack::Cache::Storage.instance.resolve_metastore_uri(metastore_uri)
entitystore = Rack::Cache::Storage.instance.resolve_entitystore_uri(entitystore_uri)

Step 3 retrieve the metadata

stored_meta = metastore.read(key)

Step 4 purge the entity store for each compression type

stored_meta.each do |sm|
  entitystore.purge(sm[1]["X-Content-Digest"])
end

Step 5 purge the metastore

metastore.purge(key)

I hope this helps.