Geolocation header

Hi,

I would like to discuss with you a proposal to solve the following use case:

Currently, the only mechanism to share your location with a website is
through the JS Geolocation API. This has some limitations: First, in order
to have the server know the client’s location there are two full roundtrips
required (one roundtrip to load the page with Javascript code, and a second
roundtrip to actually send the location to the server and get back a
location-aware response). While not as significant as the first limitation,
the second limitation is that the client must execute Javascript in order
to acquire location.

For example, for services like Search, it means that the very first
response from a server will contain non-localized results, and a second
roundtrip would be required to refresh those results (assuming Geolocation
permission is already granted for the origin).

There's many ways to solve this problem through headers, so no JS would be
required and clients could proactively include geolocation data in the very
first request (after the server asked for it in previous sessions, and
permissions are granted).

After an initial thread on GitHub
<https://github.com/httpwg/http-extensions/issues/364>, I decided to start
here the discussion so it goes through the proper channels.

Here you can find a document detailing the problem and a possible proposal
<https://docs.google.com/document/d/1zL4qyOpp6W36H4_eMpmth3Yj_ZTMZ3wCupc01q5qatA/edit>

After a bit of discussion, it looks like Client Hints (CH)
<https://tools.ietf.org/html/draft-ietf-httpbis-client-hints-04> would be a
great way to solve this use case, so I'm preparing a draft for a CH-based
approach.

It would be great to get your opinion on this, if this is something that
might be interesting for people in this working group, or whether I should
start this as an individual draft. Any recommendation?

Thanks!
Luis