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Re: Using W3C widgets in a web container: two implementations contrasted

From: Marcos Caceres <marcosscaceres@gmail.com>
Date: Wed, 28 Jan 2009 13:30:36 +0000
Message-ID: <b21a10670901280530w3ad30d92o25963041b7bdc803@mail.gmail.com>
To: Scott Wilson <scott.bradley.wilson@gmail.com>
Cc: Stéphane S. <stephane.sire@epfl.ch>, public-webapps@w3.org

Hi Scott,
On Wed, Jan 28, 2009 at 9:51 AM, Scott Wilson
<scott.bradley.wilson@gmail.com> wrote:
> Hi Marcos,
> A widget engine, in our use of the term, is a server-side web application
> that publishes widgets and implements the Widget API as a web service
> accessible via AJAX. As it stands all browsers will block any cross-domain
> Javascript requests, and this will apply in all cases where a Widget is
> making use of an external web API (e.g., a weather API, or external RSS
> feed). The only other options are:
> (1) always use JSONP calls instead of regular AJAX - but this requires
> changes at the service endpoint to support JSONP, which isn't really the
> widget ethos, which is about exposing web services in new ways without
> redesigning the services themselves
> (2) constrain widgets to only invoke web services from within the same
> domain that hosts the widget - but this is extremely limiting, and couples
> the widget engine host to the web API host.
> (3) have widgets invoke external requests via a server-side proxy offered in
> the same domain as the widget engine that is serving the widget
> If the W3 work on access policy - for allowing read-only AJAX requests -
> gets built into browsers, then the requirement for server-side proxies for
> web widgets may be less in the future, as most widgets only make GET
> requests to external web services.
> Note that Google also implements a server-side proxy for Gadgets to access
> external content, with the method "_IG_FetchContent(url, callbackFunc)",
> which is similar to the Palette approach.

Ok, I see where you are coming from now. Our definition of widget is
different. Please see the Differences from Web Widgets section in the
Widgets Landscape document [1]. Our intention is to allow the
interactions you describe to occur on the client side without
requiring assistance from the server side.

Kind regards,

[1] http://www.w3.org/TR/widgets-land/#differences

Marcos Caceres
Received on Wednesday, 28 January 2009 13:31:19 UTC

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