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Re: [CORS] Understanding the definition of simple headers

From: Monsur Hossain <monsur@gmail.com>
Date: Wed, 21 Aug 2013 21:46:04 -0500
Message-ID: <CAKSyWQ=MyqWULd3dUJQzz=ObaeqPD7sygzDUZu5RFitVZ+Phfg@mail.gmail.com>
To: Brad Hill <hillbrad@gmail.com>
Cc: "public-webappsec@w3.org" <public-webappsec@w3.org>
On Wed, Aug 21, 2013 at 10:42 AM, Brad Hill <hillbrad@gmail.com> wrote:

> The security considerations section discusses that the difference between
> simple and non-simple isn't defined by any internal logic, but by
> consistency with what existing pre-CORS user agents could already do
> cross-origin.
> If it was an existing capability of user agents that existing servers had
> to be prepared for, it was a "simple" request.

That makes sense. I just wasn't sure under what pre-CORS circumstances an
Accept, Accept-Language or Content-Language header could be set on
cross-origin requests.

> Any new cross-origin capabilities had to be gated behind a pre-flight
> check so that CORS wouldn't be creating additional risk to deployed
> servers.
> In the end, it looks somewhat arbitrary because it reflects the vagaries
> of the evolution in the previous 15 years of the Web platform.
> On Tue, Aug 20, 2013 at 10:12 PM, Monsur Hossain <monsur@gmail.com> wrote:
>> The latest CORS spec defines the simple headers as Accept,
>> Accept-Language and Content-Language. However the spec doesn't provide any
>> insight into why these particular headers are special. What is the
>> motivation for defining these as simple headers? My initial assumption was
>> that a preflight was required for any cross-origin request that couldn't be
>> done before the CORS spec existed. But its not clear to me how an author
>> could set these simple headers on cross-origin requests before CORS.
>> Thanks,
>> Monsur
Received on Thursday, 22 August 2013 02:46:31 UTC

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