Re: draft-ietf-httpbis-client-hints-04; 2.2.2. The Accept-CH-Lifetime header field

On Mon, May 8, 2017 at 6:07 PM, Mark Nottingham <mnot@mnot.net> wrote:

> > 2.2.1.  Advertising Support via Accept-CH header field
> > https://tools.ietf.org/html/draft-ietf-httpbis-client-
> hints-04#section-2.2.1
> >
> > |   Servers can advertise support for Client Hints using the Accept-CH
> > |   header field or an equivalent HTML meta element with http-equiv
> > |   attribute ([W3C.REC-html5-20141028]).
> >
> > Is it assumed that "Accept-CH" is given in http-equiv
> > attribute, but "Accept-CH-Lifetime" on http response ?
>

Yes.

> Or is that needed so that "Accept-CH" can be given
> > on several times?
>

No, that's implicit in its definition as a comma separated list of values.
Correct me if I'm wrong, but my understanding is that default semantics
allow multiple headers with same field-name, as long as the field-value is
defined as a comma separated list.. Meaning, there can be multiple
Accept-CH header fields and they can be combined into a single list.


> > What happens if there is several "Accept-CH-Lifetime"
> > on response?
>
> Ilya, any thoughts here? Clarifying these would probably be helpful.
>

For Accept-CH-Lifetime, I guess we just need to specify which one wins,
correct? Any defaults I can point to or reuse? Last one wins?

ig