AhCache: Store cached data in files

This class can store cached data in files.

It can check if a given cache file exists and it has not passed more than a given expiry time. The class checks the last modified timestamp to determine if the cache file is expired.

In that case the class can retrieve the cached data. Otherwise the class can store the cache data in a file for a given expiry period.

The cache directory is derived from the cache ID value. The class can create sub-directories to reduce the number of cache files per directory.

The class can also delete individual cache files, all cached files about a given age of one or all modules.

What is the best PHP cache whole page class?
Cache the whole Web page