Simple key-value based cache system, with file storage and reusing Wordpress options table.
Built as a proof of concept of how simple would be to do from scratch a cache component for Wordpress, not touching the core.
As such, I don't initially plan to improve anything of it, nor the TODOs section, but anyway I'll leave them.
- File-based cache sucks, but the PoC was done on a IIS 7.0 running PHP Fast-CGI, so no Apache, no APC, no Memcached.
- Having to do one MySQL query also is far from optimal, specially being wp_options and not an specific table with proper keys. That would be an improvement.
- Another option I didn't checked (for being a system call) was the modified date of the file. Should benchmark to see if worth or slower than mysql.
- Doesn't needs modifications of the WP Core, but it does need code changes in your theme(s), wherever you want to cache something (included is a sidebar example).
- Includes a very trivial Logger used for debugging.
- $_SERVER['DOCUMENT_ROOT'] was needed on all file system operations due to IIS. Probably could be removed for other web servers.