[html5] Application Cache: How are fallback entries used in the application cache selection algorithm?

Jake Archibald jaffathecake at gmail.com
Mon Jan 30 01:55:56 PST 2012


Hi,

I'm having a bit of trouble getting my head around the networking
model of ApplicationCache in regards to fallback and explicit entries.

If, without an internet connection, I open a new tab and enter a url
that matches a manifest's fallback prefix, should that fallback
resource come from the app cache? (Webkit & Firefox say yes)

If, without an internet connection, I open a new tab and enter a url
that matches a manifest's explicit extry, should that come from the
app cache? (Webkit & Firefox say yes)

If a page loads via an internet connection (not from the cache) then
the connection is lost, can that page make a successful XHR request to
a fallback resource that matches a manifest's fallback prefix? (Webkit
& Firefox say no)

The steps in http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#changesToNetworkingModel
only run if "a cache host is associated with an application cache",
and the selection of a cache
(http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#the-application-cache-selection-algorithm)
doesn't mention matching fallback prefixes or explicit entries, it
only seems to cover documents that point at a manifest.

The navigate rules
(http://www.whatwg.org/specs/web-apps/current-work/multipage/history.html#navigate)
mention application caches, but doesn't cover the case of new tabs,
where there isn't a previous or referring page.

So, are the browsers doing the right thing in the three cases above?
Which part of the spec covers the selection of a manifest in these
cases?

Many thanks,
Jake.



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