- From: Kari Hurtta <hurtta-ietf@elmme-mailer.org>
- Date: Sat, 11 Nov 2017 21:30:19 +0200 (EET)
- To: Amos Jeffries <squid3@treenet.co.nz>
- CC: Kari Hurtta <hurtta-ietf@elmme-mailer.org>, HTTP Working Group <ietf-http-wg@w3.org>, HYBI Working Group <hybi@ietf.org>, Patrick McManus <pmcmanus@mozilla.com>
Amos Jeffries <squid3@treenet.co.nz>: (Sat Nov 11 16:17:01 2017)
> If ":upgrade" has the same optional nature as Upgrade did there is zero
> point in creating it. Just use the existing Upgrade header in the
> HEADERS frame. That does not require any negotiation.
>
>
> The whole point of SETTINGS is to promise the recipient of that frame
> that the things mentioned in it will work. No maybes or guessing.
>
> This guarantee provided by SETTINGS is one of the ways HTTP/2 improves
> over HTTP/1.1. No more sending maybe-ignored headers and hoping for
> success a few RTT later. The client can know up front whether that
> connection is a usable channel for the negotiable feature or not.
>
Sidenote:
If you want SETTINGS to tell that websocket can be used
over HTTP/2 then
:upgrade =
and SETTINGS ENABLE_UPGRADE is no go. No general tunneling
as Kazuho Oku <kazuhooku@gmail.com> as suggesting in that thread:
https://lists.w3.org/Archives/Public/ietf-http-wg/2017OctDec/0209.html
> If we adjust the three issues (for example, by allowing any method to
> be specified, and use the existence of :upgrade: pseudo header as a
> signal; use 101 to signal protocol change; use attributes of :upgrade:
> header to specify additional headers required for the upgrade), I
> think the approach would become generic.
>
> For example, creating a websocket tunnel through HTTP/2 would look like below.
In that case SETTINGS ENABLE_UPGRADE tells nothing what upgrades are available
(or you need to do registry for different 32-bit values of
ENABLE_UPGRADE to map possible upgrade protocols).
Same to say about SETTINGS ENABLE_CONNECT_PROTOCOL and
:protocol =
You are asking SETTINGS ENABLE_WEBSOCKET then
and that is not proposed on draft-mcmanus-httpbis-h2-websockets-01
either.
/ Kari Hurtta
Received on Saturday, 11 November 2017 19:31:10 UTC