Implementation of an lru_cache() decorator that ignores the first argument

[Robert Latest]

Hi Chris and dh,

thanks for your --as usually-- thoughtful and interesting answers. Indeed, when
doing these web applications I find that there are several layers of useful,
maybe less useful, and unknown caching. Many of my requests rely on a
notoriously unreliable read-only database outside of my control, so I cache the
required data into a local DB on my server, then I do some in-memory caching of
expensive data plots because I haven't figured out how to reliably exploit the
client-side caching ... then every middleware on that path may or may not
implement its own version of clever or not-so-clever caching. Probably not a
good idea to try and outsmart that by adding yet another thing that may break
or not be up-to-date at the wrong moment.

That said, the only caching that SQLAlchemy does (to my knowledge) is that it
stores retrieved DB items by their primary keys in the session. Not worth much
since the session gets created and dumped on each request by SQA's unit of work
paradigm. But the DB backend itself may be caching repeated queries.

Back to Python-theory: The "Cloak" object is the only way I could think of to
sneak changing data past lru_cache's key lookup mechanism. Is there some other
method? Just curious.