Hi,
we've been talking about appcache inside Yandex. Actually we're not at all
sure that appcache is what we really want, so much as an API to use the
normal cache better. Right now we prefer to use local storage, since
appcache isn't actually helpful. Anyway, here are some use cases:
1. Initial loading.
Our SERP (and Yandex main page www.yandex.ru) uses embedded styles and
scripts for faster loading than with multiple requests for
styles/scripts/...
But users load them every time they visit the results page, because the
browser doesn't cache it. It would be nice on the first visit to extract
the styles and scripts and store them in the cache.
2. Bundles.
Sometimes we need to load several resources (js/css/json/...) before we
can actually show something to user. Like a dialog, or another complex
control. Or if it's a single page application before change "page". Again,
it's often faster to make one request than several, but it would be even
faster if we could then cache them separately:
HttpCache.store(url1, content1);
HttpCache.store(url2, content2);
...
So that later we can use the files as usual (<script>, <link>...).
3. Diffs (delta updates)
Every static file (js/css/...) has a version, e.g.
http://yandex.st/mail/1.3.8/mail.js
Whan we release a new version our users have to download it. It could be
hundreds of kilobytes (or more). But the difference between versions is
often not very big. So we want to make delta updates.
It would be nice if we could download the diff, apply it in the browser
and store the update in cache e.g.:
var oldVersion = '1.3.8';
var newVersion = '1.3.9';
var oldContent = HttpCache.get(oldUrl);
var newContent = applyPatch(oldContent, patch);
HttpCache.store(newUrl, newContent);
4. Preloading.
Well, we can use normal xhr for that but maybe we can do more with
HttpCache.
Basically we want methods for loading resources, storing them in cache,
fetching them from cache, checking if something is in the cache, ...
cheers
Chaals
--
Charles McCathie Nevile - Consultant (web standards) CTO Office, Yandex
cha...@yandex-team.ru Find more at http://yandex.com
