Re: Comments on httpbis-client-hints-01

Regarding Accept-CH: I was talking about the following text of the spec:

> When a client receives Accept-CH, it SHOULD append the Client Hint
> header fields that match the advertised field-values.  For example,
> based on Accept-CH example above, the client would append DPR, Width,
> Viewport-Width, and Downlink header fields to all subsequent
> requests.

This "all subsequent requests" is obviously intended to be qualified
somehow. It's not "all requests to all servers ever", is it? Should it
be "all subsequent requests to the same origin"? Should it be "all
subsequent requests to this resource"?

Likewise, the "SHOULD append" phrase is unclear: append to what exactly?

On Thu, Jun 2, 2016 at 12:50 AM, Ilya Grigorik <> wrote:
>> 2. The Accept-CH field seems underspecified. Is it per-resource? (and
>> if so, doesn't it duplicate Vary?) Or is it per-origin? Or does it
>> just apply to resources linked from the response?
> If we're talking about browser as "client", then the behavior is specified
> in Fetch API:
> Does it duplicate Vary: no, I don't think so, they signal different things
> to the client and they don't have same implications for upstream caches.


Received on Friday, 3 June 2016 09:49:22 UTC