It turns out that fragment caching really doesn’t play nicely with
optional headers generated by the likes of the typo:lightbox
filter. I’m not entirely sure about whether the workings of
whiteboards are quite right either.
So, until I’ve worked out what’s going on, I shall be removing
fragment caching. The file based page caching should continue
to work though.
So, I’m giving textfilters and whiteboards a long hard look. Right
now, we’re using class methods on the textfilter, but I think a better
approach would be to instantiate them on a per request basis. The idea
being that you use the same instance to format the contents of a page
and then query the textfilter instances for required headers etc.
This might be the first step to a callback based API for Typo
extensions, but I’m making not promises.