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Re: #327: Expect syntax

From: Julian Reschke <julian.reschke@gmx.de>
Date: Fri, 16 Dec 2011 23:22:59 +0100
Message-ID: <4EEBC4C3.3050604@gmx.de>
To: Alex Rousskov <rousskov@measurement-factory.com>
CC: HTTP Working Group <ietf-http-wg@w3.org>
On 2011-12-16 22:56, Alex Rousskov wrote:
> On 12/16/2011 02:14 PM, Julian Reschke wrote:
>
>> OK, I did two more changes:
>>
>> - in the grammar, allow trailing semicolons; so that "100-continue;"
>> isn't invalid (we have the same in Prefer)
>
> Any specific reason to allow that trailing semicolon? Seems like it
> should not be allowed unless Expect is already commonly used that way.

a) there's no harm

b) it's a very easy mistake to make

c) it doesn't introduce ambiguity

d) for other header fields, we have evidence that parsers already do this

For Expect:, I have no data, as it doesn't seem to be used for anything 
other than "100-continue".

> I cannot find it right now, but I think there was some text in HTTPbis
> that talked about "cleansing" of header fields before
> comparing/interpreting them (folding, removing BWS, and such). If that
> text is indeed there somewhere, does it allow an implementation to
> remove bare semicolon before comparing?

Before comparing what?

> Finally, I expect some currently compliant implementations to fail
> updated tests if a bare semicolon is allowed and must be ignored.

Will those accept things like

   foo, 100-continue

or

   foo; bar="q\ux,", 100-continue

?

Best regards, Julian
Received on Friday, 16 December 2011 22:23:59 GMT

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