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Re: [XHR2] AnonXMLHttpRequest()

From: Julian Reschke <julian.reschke@gmx.de>
Date: Wed, 03 Feb 2010 23:12:47 +0100
Message-ID: <4B69F4DF.6020603@gmx.de>
To: Tyler Close <tyler.close@gmail.com>
CC: Jonas Sicking <jonas@sicking.cc>, Maciej Stachowiak <mjs@apple.com>, Anne van Kesteren <annevk@opera.com>, WebApps WG <public-webapps@w3.org>
Tyler Close wrote:
> On Wed, Feb 3, 2010 at 1:32 PM, Julian Reschke <julian.reschke@gmx.de> wrote:
>> Tyler Close wrote:
>>> On Wed, Feb 3, 2010 at 1:00 AM, Jonas Sicking <jonas@sicking.cc> wrote:
>>>> Another thing that might be worth noting is that if the UA contains a
>>>> HTTP cache (which most popular UAs do), the UA must never use a cached
>>>> response that was the result of a request that was made with
>>>> credentials, when making a request without. The same goes the other
>>>> way around.
>>> I gather this is because sites do not reliably use the Vary header?
>> "When a shared cache (see Section 13.7) receives a request containing an
>> Authorization field, it MUST NOT return the corresponding response as a
>> reply to any other request, unless one of the following specific exceptions
>> holds:..."
>> <http://greenbytes.de/tech/webdav/rfc2616.html#rfc.section.14.8>
> AFAICT, RFC 2616 only does a special case for the Authorization
> header, which leaves me wondering what shared caches do for other
> kinds of credentials, such as cookies or the NTLM authentication that

Cookies require

   Vary: Cookie

on the response. Or something more drastic.

> Jonas referred to. For example, if an origin server responds to a
> request with cookies by sending a response with no Vary header and no
> Cache-Control: private or other disabling of caching, would the proxy
> use the response to respond to a later request without cookies? Do

If it follows the applicable specs to the letter, yes (I believe).

> proxies commonly implement a special case for the Cookie header,
> similar to the Authorization header? Do origin servers commonly have
> this bug?

That would be interesting to find out.

We know that "Vary" doesn't work well in practice because of all the 
bugs^^^^shortcomings in IE.

Best regards, Julian
Received on Wednesday, 3 February 2010 22:13:30 UTC

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