RE: First reactions to mandatory draft
From: Paul Leach (paulle@microsoft.com)
Date: Tue, Jan 20 1998
Message-ID: <5CEA8663F24DD111A96100805FFE6587203985@red-msg-51.dns.microsoft.com>
From: Paul Leach <paulle@microsoft.com>
To: "'Scott Lawrence'" <lawrence@agranat.com>
Cc: Rohit Khare <rohit@bordeaux.ics.uci.edu>, frystyk@w3.org, ietf-http-ext@w3.org
Date: Tue, 20 Jan 1998 11:58:06 -0800
Subject: RE: First reactions to mandatory draft
> ----------
> From: Scott Lawrence[SMTP:lawrence@agranat.com]
> Sent: Tuesday, January 20, 1998 11:41 AM
> To: Paul Leach
> Cc: Rohit Khare; frystyk@w3.org; ietf-http-ext@w3.org
> Subject: Re: First reactions to mandatory draft
>
>
> >>>>> "PL" == Paul Leach <paulle@microsoft.com> writes:
>
> PL> Numeric perfixes aren't to allow multiple instances of the _same_
> extension
> PL> in one message -- they are to guard against the possibility (to use
> your
> PL> example) that two independent parties design an extension, and both
> call it
> PL> "Skidoo" (but they will have different URLs for the extension, of
> course),
> PL> and still allow both to be used in one request.
>
> I think that having different URLs to identify the extentions is
> sufficient; if the extentions are so incompatible that they cannot
> be used in the same header syntax unambiguously, then they shouldn't
> be implemented in the same place anyway.
>
What? First, if two groups invented the extension independently, there will
almost certainly be _no_ relation between them. Second, if there's just a
URL, how can you tell which headers go with that URL?
> I don't want to have to (won't) implement a parser that can deal
> with:
>
> GET /xyz HTTP/1.1
> Host: foobar
> 23-Skidoo: abc
> 65-Skidoo: def
> Man: "http://screwball.org/skidoo.html"; ns=23-,
> "http://nutcase.org/skidoo.html"; ns=65-
>
> by having to backtrack my parser to remove the 23- and recognize the
> 'Skidoo'; by the time I get to the Man header, I've seen the
> two numeric prefix headers and discarded them as unrecognized (and
> therefor automatically optional) headers.
>
This is independent of the use of numerical prefixes. I always thought it
was obvious that the Man header was required to come _ahead_ of any uses --
but I can't recall if the spec _says_ that.
> Even supposing hypothetically that we did do this, what happens to
> the headers now - granted we separated them for transmission, but
> internally the values will be combined anyway as though they were
> sent as
>
> Skidoo: abc, def
>
> because that is what header folding rules say we should be able to
> do.
>
23-Skidoo and 65-SKidoo are _not_ the same header, so they shouldn't be
folded.
> We're close to having a registry for header field names anyway; I
> just don't think that this extra complexity is warranted.
>
It seems that at least some of the complexity is due to a misconception.
Paul