Alpstein/route-me — pull request #61 by incanus (2012-05-18 19:02:57+00:00)
Title: configurable cache expiration handling

This is some functionality to provide for time-based tile cache removal. It adds an `expiryPeriod` property to `RMDatabaseCache` (this doesn't really make sense for memory cache). It also adjusts `RMTileCache` to setup the database cache with an `expiryPeriod` of zero by default, which means not to use the time-based cache (and makes the quantity-based cache check first that time-based isn't used), as well as adds parsing to the file-based configuration options to set `expiryPeriod` there. It uses a 1% garbage collection frequency to do the actual time-based cache purging, as well as the already existent `last_used` column in the database store, which doesn't get updated unless the LRU purge method is being used.