Re: What is the HTTP/1.1 equivalent of ":scheme" in HTTP/2 and HTTP/3?

On Wed, Mar 22, 2023 at 4:28 AM Martin Thomson <mt@lowentropy.net> wrote:

>
> In HTTP/1.1, scheme can be explicit if the authority form is used.
> However, in most cases the scheme is inferred from properties of the
> connection.  That is, if TLS is in use, infer "https"; otherwise, infer
> "http".
>
>
The gateway text covers those cases where you have cleartext to the gateway
> and TLS to an origin server (not that common now) or the scary case of TLS
> to the gateway and cleartext to the origin (shockingly, still more common
> than I'd like).  In those cases, the gateway might use absolute form as you
> say.  Forwarded-For (https://www.rfc-editor.org/rfc/rfc7239#section-5.4)
> has a parameter that might signal this.
>
> Signals might also be implicit - if there is only an "http" front end, the
> origin server can assume "http" even when the request from the gateway
> comes in over TLS.  That's probably very common as it is increasingly less
> common to have both "http" and "https", as the latter is superior in nearly
> every way.
>
>
Got it, thanks for your detailed explanation. So the absolute-form can be
explicitly used, but RFC 9112 (HTTP/1.1) says it is intended to be used for
sending requests to proxies, although origin servers are required to
support it. This is in fact not exactly equivalent to ":scheme", as
":scheme" has no restrictions. Am I right?

-- 
Best regards,
Zhang Jingcheng
Beijing, China