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Re: p2: Expectation extensions

From: Amos Jeffries <squid3@treenet.co.nz>
Date: Wed, 24 Apr 2013 01:57:54 +1200
Message-ID: <51769362.808@treenet.co.nz>
To: ietf-http-wg@w3.org
On 23/04/2013 7:22 p.m., Mark Nottingham wrote:
> p2 5.1.1 requires that an unrecognised expectation be replied to with a 417 Expectation Failed.
>
> In my testing, it's fairly common for servers to ignore an unregistered expectation (e.g., "foo").
>
> Given how many problems we already have with Expect, should we consider disallowing further extensions here, and removing this requirement?

So whats gained by making it an expectation if the expectation is 
ignored? nothing.

Removing it also removes the fail-closed property of Expect:. I know the 
property is a great annoyance to new featrue rollout. But it does offer 
the concrete assurance that what is expected is supported which is quite 
useful when designing security related extensions. We have the Prefer 
header coming up to provide the expectation negotiation with fail-open 
semantics.

So overall I think we keep this, the servers not implementing it are 
already non-conformant with Expect.

Amos
Received on Tuesday, 23 April 2013 13:58:22 UTC

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