[Mediawiki-api] Special page-rendering for certain visitors

[Mikhail T.]

Hello!

I run a small site, where only the registered users currently have
access to articles. I'd like to allow anonymous visitors to see the
first and the last paragraph of a page, instead of simply demanding,
they log-in.

Extension-writing seems simple enough, but all of the hooks in the
`*Page Rendering'* section of the list at:

    http://www.mediawiki.org/wiki/Manual:Hooks

seem to apply to an article /regardless of the visitor/. The result of
the rendering is then cached and sent to all subsequent visitors... This
means, that if the first user to access a page is a guest, even the
registered users will see the truncated page. And the other way around
-- if the first user is registered, everyone will the full content of
the page rendered just for him...

Short of disabling caching altogether, how can I send an abridged
version to guests without affecting the logged-in users? Thank you!

    -mi