Cache Handler Function As an alternative to using the default file-based caching mechanism, you can specify a custom cache handling function that will be used to read, write and clear cached files. Create a function in your application that Smarty will use as a cache handler. Set the name of it in the $cache_handler_func class variable. Smarty will now use this to handle cached data. The first argument is the action, which will be one of 'read', 'write' and 'clear'. The second parameter is the Smarty object. The third parameter is the cached content. Upon a write, Smarty passes the cached content in these parameters. Upon a 'read', Smarty expects your function to accept this parameter by reference and populate it with the cached data. Upon a 'clear', pass a dummy variable here since it is not used. The fourth parameter is the name of the template file (needed for read/write), the fifth parameter is the cache_id (optional), and the sixth is the compile_id (optional). example using MySQL as a cache source