We did exactly this for Nameplanet in'99. Started with plain Maildir, the added more info in the filename as new mails were found, or status changed.
We finally added a cache of some data in a dot-file (that'd just get blown away and recalculated if it failed a format check).
It made a very slightly enhanced POP3 server sufficient for a web frontend with good performance.
But all the changes to the Maildir was optional - any software that didn't support it could still operate on them and the missing bits would just get recreated.
We finally added a cache of some data in a dot-file (that'd just get blown away and recalculated if it failed a format check).
It made a very slightly enhanced POP3 server sufficient for a web frontend with good performance.
But all the changes to the Maildir was optional - any software that didn't support it could still operate on them and the missing bits would just get recreated.