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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:

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

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
control.

Can anyone see a way around this problem using HTTP?

--
Marcos Caceres
http://datadriven.com.au
Received on Wednesday, 2 July 2008 06:21:48 GMT

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