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[widgets] ETags and Automatic updates

From: Marcos Caceres <marcosscaceres@gmail.com>
Date: Wed, 2 Jul 2008 16:21:07 +1000
Message-ID: <b21a10670807012321v51bcd7a6n3c4f7e923f17db13@mail.gmail.com>
To: "Web Applications Working Group WG" <public-webapps@w3.org>

It was previously suggested that we use ETags as a way of managing
widget updates. The idea was that we would include and ETag attribute
in the <update> element:

  <update etag="?????" url="http://bla.com/updates/my.wgt">

The problem is that it's impossible for the widget author to know what
the ETag for a widget is going to be until the widget is served over
HTTP (unless they know how to set it themselves somehow on the server
- which I personally have no idea how to do). So, once the author gets
the etag, modifies the <update> element, and then puts the widget back
on the server, the server will again change the ETag! and so it goes
ad infinitum.

This problem arises because users can acquire a widget from sources
other than HTTP (e.g. BlueTooth, local storage, etc.), and so we don't
initially have access to any of the usual HTTP headers for cache

Can anyone see a way around this problem using HTTP?

Marcos Caceres
Received on Wednesday, 2 July 2008 06:21:48 UTC

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