Class Cache: Caching data in files of a given folder

This class is capable of caching arbitrary data in files of a given folder.

This is meant to help reducing the time it takes to serve the same content of pages that would take a long time to generate and would slow down the access to such pages if they had to regenerated everytime when not using content caching.

The class works by checking if a cache file with a given key exists and it was not created since a longer time than the cache expiration period. If it does not exist or has expired, the data is stored in a cache file. Otherwise the data is retrieved from the cache file.

The class uses the MD5 algorithm to generate the names of the files on which the cached data is stored.

If the folder where the cache files are created does not exist, the class can create it and also store in them an empty index.html file and a .htaccess file with permissions set to deny access to the files via the Web in case you are using Apache as Web server.

The default cache expiry time is 86400 seconds. The default cache folder is the ./cache. You can change these values when the cache class object is created using the class constructor of ant time later the updateCache function.