More Information

More detailed information is available at http://gom-jabbar.org/articles/2008/12/15/introducing-mint-store-a-strategic-store-for-merb-cache

Mint Store is...

It's basically a port of Disqus MintCache with two additionnal features:

• When you use fetch (and provide a block), if the cache is stale, Mint Store will return the stale cache and update the cache (with the result of executing the provided block) after the request has been served using Merb.run_later
• Deletion will just mark the cache as stale which will cause the next fetch to repopulate the cache.

Read and Fetch

Read returns nil the first time the cache becomes stale and then returns the stale cache for :mint_delay seconds.

So on the contrary to using fetch where none of the clients will be penalized, if you use read, you will penalize one clients who will have to wait for the cache to be refreshed before his request is served.

Note: fetch_fragment and fetch_partial from merb-cache both use fetch

Initialization Options

Mint Store accepts several initialization options:

• Behaviour options:
  • :force_delete if set to true, delete will just delete the data from the cache
  • :need_expire_in if set to true, writable? will return false if the :expire_in condition is not present. If you are going to use MintStore with the AdHocStore it makes sense to set it.
• Default values:
  • :mint_delay : the difference between the stale date (that you provide by :expire_in) and the real :expire_in given to memcached (default: 30s)
  • :refresh_delay : the :expire_in value given to memcached while regenerating the cache (can set to 0 if you want memcache to never expire the stale cache while waiting for it to be refreshed)
  • :expire_in : default value for the stale date if not provided (default: 300s)

Example: setting the options

code:ruby register(:memcached_store, Merb::Cache::MemcachedStore) register(:mint_store, Merb::Cache::MintStore[:memcached_store], :need_expire_in => true, :refresh_delay => 0)