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Generalization of Service Worker external events

From: Andy Valencia <ajv-efurgetonrit@vsta.org>
Date: Tue, 28 Mar 2017 20:04:21 +0000 (UTC)
To: public-webapps@w3.org
Message-Id: <20170328200421.C934140254@vsta.org>
Service Workers ("SW") were obviously initially motivated by the
need for a more flexible offline app architecture.

Because they do not share the DOM of the original registration,
they are much lighter weight.  Thus, it is reasonable for their
continued existence even after the (possibly automated) clearing
of the original registration page.

To defend against various zombie-ware abuses, their state is forced
inactive soon after the associated page goes away.

In pursuit of an approach for presence and notification dispatch,
they were enhanced to support returning to run state from a
(browser specific, possibly proprietary) push event.  (They were
also given a Notification API to make these events visible.)

Would there be any interest in generalizing the ability to
resume a SW from remote events?  I'm mostly thinking in terms
of accomodating long polling techniques, but most important
is that whatever's used is open and decentralised.

One approach would be to have Notification.requestPermission
accept a "server" option.  Either a SW with an active fetch
to that server is left in run state, or perhaps the SW
can be stopped while maintaining the pending fetch.

Alternatively, Chrome's "background fetch" is actually a pretty
good fit; just run long polling across its managed fetches.
Of course, there might be some puzzled users on seeing your
long polling app listed under the "active downloads" list.
But in terms of technology mechanism, it's a very good fit.

Service Workers started as a flexible caching solution, but they
really are just a lightweight background thread with a RESTful API.
Given a little more app control over their background operation, they
could become a very flexible, very powerful agent serving the main
web app while it is in the background, during network interruptions,
and also low memory situations where the app's tab has been retired.

While, of course, keeping them from becoming soul-sucking zombies.

Thanks,
Andy Valencia
Received on Wednesday, 29 March 2017 12:24:54 UTC

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