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Re: Is SMTP really part of the Web Architecture?

From: Mark Nottingham <mnot@mnot.net>
Date: Mon, 9 Sep 2002 11:07:36 -0700
Message-ID: <010c01c2582b$cb7bc740$6900200a@mnotlaptop>
To: <www-tag@w3.org>
Cc: "Mark Baker" <distobj@acm.org>

I'm very interested to hear the TAG's views on this, especially regarding
test (b). Is it the case that something that is stateful and fine-grained,
in as much as it cannot be usefully gatewayed to HTTP, cannot be part of
the Web?


----- Original Message -----
From: "Mark Baker" <distobj@acm.org>
To: "Elliotte Rusty Harold" <elharo@metalab.unc.edu>
Cc: <www-tag@w3.org>
Sent: Monday, September 09, 2002 8:20 AM
Subject: Re: Is SMTP really part of the Web Architecture?


>
> Elliotte,
>
> On Mon, Sep 09, 2002 at 10:05:17AM -0400, Elliotte Rusty Harold wrote:
> > SEction 1 of the arch draft states:
> >
> > Protocols. A small and nonexclusive set of protocol specifications
> > for interchanging information between agents, including HTTP
> > [RFC2616], SMTP, and others. Several of these protocols share a
> > reliance on the Internet Media Type (or, "MIME") the
> > metadata/packaging system [RFC2046].
>
> Just to be clear, because I think the draft is, SMTP is said to be
> included as part of the Web, not of Web architecture per se.
>
> > I am not sure SMTP properly belongs here for a number of reasons:
> >
> > 1. SMTP significantly predates the rest of what we call the Web.
>
> As do a lot of other protocols.  But, while not being privy to the TAG
> discussions that concluded that it be mentioned, I think the key point
> here is that Web architecture *subsumes* a substantial part of many
> other systems.  Specifically, for SMTP, SMTP end point identifiers
> (email addresses), have been subsumed via URI-izing.  In addition, the
> SMTP "DATA" method can, to a meaningful (though incomplete) extent, be
> subsumed by HTTP POST.
>
> By "incomplete" I mean that some SMTP features would be lost in this
> subsumption, but it could still be done, and email messages could be
> sent.
>
> IMO, a litmus test about whether another system could be counted as part
> of the Web would be;
>
> a) are the operations of this system performed on things with
> identity (i.e. can they be URI-ized)?
> b) could an HTTP gateway be constructed which mapped the application
> interface of this system to HTTP's application interface (perhaps
> extended), while preserving enough of the other system's functionality
> to be useful?
>
> In my definition, a) is necessary and sufficient for a system to be
> counted as part of the Web.  This would include SMTP, FTP file transfer,
> telnet sessions, etc..  However, of those, I believe that only SMTP and
> FTP could be usefully interacted with via HTTP's interface.  Telnet,
> by virtue of its stateful, fine-grained messages, could not usefully
> be wrapped.
>
> So there's certainly degrees of "being part of the Web".
>
> > Note that the same arguments apply to NNTP and Usenet news. FTP and
> > gopher, by contrast, though not traditionally W3C protocols, are at
> > least similar enough in structure to HTTP to justify being included.
> > HTTPS obviously can be included.
>
> NNTP is another example of a system that would probably pass both a)
> and b) above.  GET to retrieve news articles, POST to send them (indeed,
> IIRC, the HTTP method name "POST" was taken from NNTP), URIs to
> identify the server/group and individual articles.  However, the current
> deployed subsumption of Usenet only meets the criteria in a) (i.e. you
> can click on news:alt.foo.foo and your newsreader pops up).
>
> MB
> --
> Mark Baker, CTO, Idokorro Mobile (formerly Planetfred)
> Ottawa, Ontario, CANADA.               distobj@acm.org
> http://www.markbaker.ca        http://www.idokorro.com
>
Received on Monday, 9 September 2002 14:09:05 GMT

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