Re: 103 (Early Hints) vs. response headers

[Vasiliy Faronov <[e-mail]>]

Kazuho, thank you for clarifying.


On Fri, Feb 24, 2017 at 4:34 AM, Kazuho Oku <[e-mail]> wrote:
> I think that the client should discard it, because (contrary to the
> expectation) the server did not include the Warning header in the
> final response, and because the draft states that:
>
>    However, the evaluation MUST NOT affect
>    how the final response is processed; the client must behave as if it
>    had not seen the informational response.

This makes 103 a special case in HTTP processing, sort of like HEAD or
204. A client that understands 1xx, but doesn't know 103 specifically,
would handle such a header differently.

If, instead, you defined headers on a 103 response as applying *both*
to the 103 response *and* to the final response (speculatively), then
there would be no such special-casing, while rel=preload would work
the same. (Content-* might still need special-casing for 103, but they
are already defined in terms of "associated representation" for the
special case of HEAD.)

Of course, this won't be a problem in practice if 103 is only used for
rel=preload. This isn't causing me any trouble, just something I
wanted to point out for your consideration.


-- 
Vasiliy