On Mon, Apr 28, 2014 at 3:01 PM, Gergo Tisza <gtisza(a)wikimedia.org> wrote:
Part of imageinfo is parsed from templates on the file
description change,
assuming those templates add the right markup to annotate the data they
contain. We want to get communities to make their local templates behave
similarly to the ones on Commons, so they can also be parsed; this is
important for both MediaViewer and for eventually moving image metadata
into Wikibase. This means editors will need to tweak a lot of templates and
verify that the data is parsed correctly; if between the tweaking and the
verification there is a one-day caching period, that would kill all such
efforts.
I guess if either server load or roundtrip lag becomes a big issue, we
could write some sort of separate gadget which editors could use to verify
the API results, while MediaViewer could use caching, but that should be a
last resort.
On second thought, the important part of imageinfo (iiprop=extmetadata) is
currently cached for 12 hours without invalidation for remote files. While
that is something that should eventually be fixed, for now we wouldn't lose
anything by caching imageinfo requests to non-local files for a few hours;
that should cover the large majority of requests. Also, it's the local
templates that need community effort, so the caching of metadat of remote
files wouldn't have much effect on that.