Rails Expire action using regex expression with Memcache - regex

Question

Iam working on a Rails application and have integrated caching with memcache using Dalli. Iam working on action caching and expiring cache using sweepers.
My sweeper code looks like this:
class BoardSweeper < ActionController::Caching::Sweeper
observe Board
def after_create(board)
expire_cache(board)
end
def expire_cache(board)
expire_action :controller => :boards, :action => :show, :id => "#{board.id}-#{board.title.parameterize}"
end
end
But I want to delete the cache using regex expression i.e. I want to match the url and delete the cache just like:
If my board show url's are like:
"boards/1/likes-collection-of-branded-products.text/javascript"
"boards/1/likes-collection-of-branded-products.text/html"
Then I want to use the following expression to expire the cache:
Rails.cache.delete_matched(/boards\/1.*/)
But as per the memcache api doc it doesnt support delete_matched method.
Iam sure there should be some way to delete on basis of regex. Please help.
Many Thanks!!

Answer 1

afaik the problem with memcached is that there is no simple way of retrieving all keys. that's why there is no such functionality as expiring based on a regular expression.
what you could do:
use a naming convention for your cache keys and simply expire all cache keys that you know of, that might have been created.
this would impose a little overhead by expiring keys that have not been created.
overall, i would not advise you using action-caches. there are good reasons that those got excluded from rails4.

Answer 2

You could try Gibson cache server as your primary cache store, it supports multiple keys invalidation by prefix in O(1) time due to its internal data structure, in your case it would be just a matter of:
Rails.cache.delete_matched "boards/1/"
An ActiveSupport extension is being developed and will be released in about a week.