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Re: Cross domain resource

From: Dirk Schulze <krit@webkit.org>
Date: Sat, 3 Nov 2012 21:14:09 -0700
Cc: Erik Dahlstrom <ed@opera.com>, Dirk Schulze <dschulze@adobe.com>, "www-svg@w3.org" <www-svg@w3.org>
Message-Id: <BDACDF13-6B15-4185-800C-D2E519828BBA@webkit.org>
To: Boris Zbarsky <bzbarsky@MIT.EDU>
Am 29.10.2012 um 07:20 schrieb Boris Zbarsky <bzbarsky@MIT.EDU>:

> On 10/29/12 5:48 AM, Erik Dahlstrom wrote:
>> SVG Tiny 1.2 does require support for some external resources (e.g
>> <use>), see [1].
> 
> Ah, perfect. http://www.w3.org/TR/SVGTiny12/linking.html#externalReferences is actually the text I had been looking for.
> 
> Note that this text presents another incompatibility between the processing models for external references and images as far as I can tell: Once you load http://foo/bar.svg#x as an external resource for a given document, loading http://foo/bar.svg#y as an external resource for a given document MUST per Tiny12 use the same bar.svg no matter what the cache headers and whatnot say.  I'm fairly certain that's not the case for images, at least in Gecko: images are coalesced based on full URI, not URI-minus-fragment-ident, and even then there is room for cache invalidation, I think.

Actually that makes SVG stacks useful. If the browser needs to send requests for the same resource over and over again, this would kill the benefit of SVG stacks. Furthermore, some servers like the W3C server delay requests of the same resource, even if the fragment differs on every request. This leads to serious loading issues on Filter Effects[1] for WebKit, which doesn't have this optimization either.

Greetings,
Dirk

[1] https://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/index.html

> 
> And Tiny12 requires that as well, actually:
> 
>  References to any other kinds of document, such as media or external
>  scripts, are not classified as primary or resource documents.
>  Multiple references to media at a particular IRI always result in
>  separate timelines being created.
> 
> (Of course Tiny12 also says that script must run in the external resource document, but that's a separate problem.)
> 
> -Boris
> 
Received on Sunday, 4 November 2012 23:03:06 GMT

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