Re: [csswg-drafts] [css-mediaqueries] Expose User Preference Media Queries as HTTP Client Hint or HTTP Header (#4162)

> https://httpwg.org/http-extensions/client-hints.html defines the infrastructure but not the headers that use it. Those are defined elsewhere (e.g. https://wicg.github.io/netinfo/)

@yoavweiss This was my understanding, thanks for confirming.

> So you could define those headers either here (if the editors and the WG are OK with that) or as a separate spec.

@tabatkins Question to the CSS WG: are you fine with spec'ing such a header or client hint here?

One important remark: since `Accept-CH-Lifetime` was [removed from draft 07](https://httpwg.org/http-extensions/client-hints.html#since-07) (I think this is the relevant [discussion that caused its removal](https://github.com/httpwg/wg-materials/blob/gh-pages/ietf105/minutes.md#issue-active-vs-passive-fingerprinting)), currently a client hint would not suffice, as it would only be sent for subresource requests, but not the main document (which would be needed for the inline CSS use case to be covered). Quoting from the [demo](https://client-hints-demo.appspot.com/): *"If the `Accept-CH-Lifetime` duration is omitted, then the opt-in only applies for subresource requests of the document advertising the `Accept-CH` policy"*.

Given the above, we are left with defining a whole new HTTP header that gets sent unconditionally (like `Save-Data`), or the HTTP WG needs to reconsider the `Accept-CH-Lifetime` decision. Please advise, @yoavweiss and/or @igrigorik.   

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Received on Thursday, 1 August 2019 11:44:19 UTC