Re: No-Vary-Search

Hey Jeremy,

> This was originally No-Vary-Query, but the web-exposed APIs call this
part of the URL "search", so this change was requested in a W3C discussion.

I can understand why you changed the name from "No-Vary-Query", but given
that it's primarily a mechanism to change the way that content is cached, I
think it makes sense to call it "No-Vary-Cache"

I think this document needs a high-level overview section, explaining what
you're trying to do and what specific problems you're trying to solve.
You're clearly deep in the weeds on it (I don't mean that pejoratively!)
but for those of us that are coming at it fresh, it needs something there
to tell us about the idea/project.

On Tue, Feb 20, 2024 at 6:14 PM Jeremy Roman <jbroman@chromium.org> wrote:

> Hello HTTPWG:
>
> This is tangentially unrelated to my previous email, but I've split it
> into another thread to avoid entangling the two.
>
> A developer previously reported to us that their ability to use the
> prefetch cache was limited because their prefetch request URLs needed to
> include certain query parameters which are different from the navigation
> request URL, even though these URLs do not affect the resource the server
> ultimately produces (and therefore, the client can safely use the
> resource). The explainer
> <https://github.com/WICG/nav-speculation/blob/main/no-vary-search.md> we
> wrote goes through some of the possible use cases in more detail.
>
> The semantics we have right now (and the header name, No-Vary-Search¹) are
> designed with the concept of being implementable in non-browser HTTP
> implementations, but since browser use cases were what we are focused on,
> there are some places where the semantics rely on, e.g., WHATWG URL
> <https://url.spec.whatwg.org/>, which may vary in subtle ways from other
> concepts of the meaning of the query string (since IETF HTTP doesn't
> currently take a position on that as far as I know).
>
> The specification draft
> <https://wicg.github.io/nav-speculation/no-vary-search.html> is currently
> hosted by the W3C's Web Incubator Community Group (WICG) and we've
> previously discussed it in a W3C context, but it was suggested that we
> bring it to HTTPWG's attention, too, and if there is interest among
> participants it could migrate to an HTTPWG RFC instead of continuing
> incubation in the web standards venues.
>
> ¹ This was originally No-Vary-Query, but the web-exposed APIs call this
> part of the URL "search", so this change was requested in a W3C discussion.
>


-- 
Rory Hewitt

https://www.linkedin.com/in/roryhewitt