Subject: Ftp-WG: LIST format documentation

From: Dave Cridland <[email-masked]>
Date: Mon, 25 Oct 1999 08:17:59 -0400

Yes, RFC 959 itself dictates exactly the format to be used for LIST - human
readable. Beyond that, it's anyone's guess. Although actually, I can't even
find where it says it has to be human readable - it just says the
information may be of use to humans.

I'm not even sure, given the explanation of the term ASCII in RFC 959, that
the UTF-8 names can actually be transferred in the response to LIST.

There's absolutely nothing in the specification which suggests that the list
of files needs to be anything more technically specified than a string of
prose with, "Gosh, look, there's a file here called 'fish.html', now, would
you beleive that? Amazing, isn't it?". The contents are entirely in the eye
of the implementor.

There's nothing stopping us from suggesting that FTP server implementors
ought to stick to certain LIST formats, though - however, I'd be loathe to
suggest something other than UNIX LIST format, and since my own servers
produce this by hand, as it were, rather than simply spawning /bin/ls, then
I'm no fan of it. But it's something that any client which attempts to
automatically parse LIST formats *will* understand.

EPLF is a great idea. I personally think MLST shows more potential, however,
and I think the realism of it's implementation plan (it doesn't actually
have one as such) shows more promise of it actually happening.

That alone doesn't rule out EPLF, in my book. What does, however, is the
simple problem that various ancient clients will break - that's something
that has to be made avoidable. It would be bearable if there was a clear
indication of *why* these clients broke, but given the number of times I see
misconfigured UNIX servers giving no directory listing at all, I doubt that
it'd be easy to trace for the vast, huge, majority of people on the net.

Ancient clients will still perform all the appalling errors and
innefficiencies that they do today with MLST, but that's a known factor,
and, as you quote Alun's message of three years ago, old software doesn't
get upgraded.

I agree with Alun - ultimately, it'd be nice if MLST replaced LIST entirely.
I hope that'll happen. It might happen. I also agree with his comment you so
carefully preserved of three years ago, that old functionality - like PORT,
like LIST - must be preserved because of the logistical nightmare of old
software.

People don't, as a general rules, upgrade unless they really have to, and,
more importantly, they *know* they really have to. It's a pain, and I have
great sympathy for the thousands of people working in technical support at
ISP's who would, in the hypothetical world of EPLF, suffer millions of calls
from irate people demanding to know why 'their internet' had stopped
working.

-----Original Message-----
From: D. J. Bernstein [mailto:[email-masked]]
Sent: Saturday, October 23, 1999 2:05 PM
To: [email-masked]
Subject: Ftp-WG: LIST format documentation

[...]

It's not my fault that the IESG refuses to publish documentation of
existing RFC-959-compliant FTP LIST formats.