time based cache expiry for rails action cache

rails has excellent support for caching action, page, query and so on.
rails default behavior is more than expected for most of the project. though i was looking for some time based expiry function on “caches_action” functionality. unfortunately there wasn’t anything so here is a simple trick i have used to make it work with different url and time based expiration.

i added “caches_action :recent” on my controller and added the following protected method -

protected
def fragment_cache_key(p_args)
cache_key = “cache_key_#{request.path}#{request.headers["QUERY_STRING"]}”.gsub(/=/, “”)
action_cache_key = get_from_cache(cache_key)
if action_cache_key
return action_cache_key
else
action_cache_key = Digest::MD5::hexdigest(“#{rand}#{Time.now}”)
add_to_cache(cache_key, action_cache_key, {:expiry => 1.hours})
return action_cache_key
end

end

actually i generate key and stored them inside my memcached instance with an hour expiry limit.
so when memcache invalidates my cache my action cache is also get invalidated.

so thus rails default action cache work with time limit

don’t think this is all, i suppose to cleanup the previously created cache file so i won’t get unnecessary store consumption .