Re: [art] Revising BCP56: On the use of HTTP as a Substrate

[Adam Roach <[e-mail]>]

On 7/15/17 16:25, Ted Hardie wrote:
> On Sat, Jul 15, 2017 at 4:09 PM, Mark Nottingham <[e-mail] 
> <mailto:[e-mail]>> wrote:
>
>
>     > On 15 Jul 2017, at 11:20 am, Adam Roach <[e-mail]
>     <mailto:[e-mail]>> wrote:
>     >
>     > I found 4.3.2 particularly interesting, as there doesn't seem to
>     have been consensus in this space in the past. For example, the
>     ws(s) and ipp(s) schemes made a different decision. I presume your
>     assertion is that, were we defining these protocols today, they
>     would be using http(s) instead?
>
>     AFAICT IPP doesn't use the HTTP port, scheme nor HTTP's
>     registries, so as per section 2, it's not "using" HTTP.
>
>
> RFC 7472 describes the  HTTPS tranport binding and its relationship to 
> the ipps scheme (it's a successor to some previous work doing similar 
> things for HTTP).  It notes:
>
> The IPP Client converts the 'ipps' URI to an 'https' URI [RFC7230 <https://tools.ietf.org/html/rfc7230>]
>        (replacing 'ipps' with 'https' and inserting the port number from
>        the URI or port 631 if the URI doesn't include an explicit port
>        number);
> While the default isn't the existing HTTPS port, it's my understanding 
> that in some deployments the ipps scheme uses the HTTPS port and so 
> ends up with an HTTPS scheme message over the standard HTTPS port.

You don't have to rely on the ipps spec for this -- the original design 
of IPP has a similar transformation for ipp URLs; RFC2910 stipulates:

    Because the HTTP layer does not support the 'ipp' scheme, a client
    MUST map 'ipp' URLs to 'http' URLs, and then follows the HTTP
    [RFC2616][RFC2617] rules for constructing a Request-Line and HTTP
    headers.  The mapping is simple because the 'ipp' scheme implies all
    of the same protocol semantics as that of the 'http' scheme
    [RFC2616], except that it represents a print service and the implicit
    (default) port number that clients use to connect to a server is port
    631.

Mark -- if you think the guidance in your document wouldn't apply in 
these cases, you'll have to be clearer by what you mean when you say 
'The URL scheme "http" or "https" is used': I would have thought this 
qualifies.


/a