Path: utzoo!utgpu!news-server.csri.toronto.edu!smoke.cs.toronto.edu!moraes
Newsgroups: news.software.b
From: moraes@cs.toronto.edu (Mark Moraes)
Subject: Re: The anomolous handling of bad dates in cnews.
Message-ID: <91May24.004646edt.2188@smoke.cs.toronto.edu>
Organization: Department of Computer Science, University of Toronto
References: <b8bHel-b@cs.psu.edu> <1991May23.115029.10971@mp.cs.niu.edu> <91May23.151914edt.1030@smoke.cs.toronto.edu> <1991May24.032746.1237@mp.cs.niu.edu>
Date: 24 May 91 04:47:01 GMT
Lines: 48

Neil, I did not say that your mailing list gateway using posting dates
was dangerous.  (our mailer rewrites all dates to conform to RFC1123,
else I'd probably have had to do the same for our mail2news gateway)

By caution, I meant (ambiguously:-) that *inews* replacing *ambiguous*
dates with the current date, or trying to fix up dates that were
*ambiguous* is not safe.  I claim it isn't safe because I suspect that
one day it will fix the date incorrectly and will cause a mess as a
result (I can't guess what the mess will be or why it will happen --
it's merely my respect for Murphy).  I agree, this is an irrational
fear.

Modulo bugs, the current inews (well, anne.jones) rewrites unambiguous
Dates to the correct syntax without losing information or changing the
date by more than a day.  And it is very generous with the dates it
accepts -- its timezone table may be a bit flaky but it will merely
ignore timezones it cannot understand.  (All words it cannot
understand are assumed to be flaky timezones, if the code hasn't
changed since I last saw it) If the date is ambiguous, replacing it
with the current date means one is potentially changing information
that is used to order the article in newsreaders and reject the
article in transport.  If the rewrite of the ambiguous date results in
a date in the future, it will result in the article being tossed.  A
parallel thread in this newsgroup indicates how some people react to
this :-) Contrary to some assertions in that thread, I've seen the
authors of C News take great care to avoid dropping news unless
there's no reasonable alternative.

C News relaynews does not rewrite headers and has a stricter parser
partly because it makes a performance/size difference, and this was
deemed to matter, especially around the University of Toronto where
some of the news machines are Sun3/[12]80s that are also used as file
servers or time-sharing machines. and consequently haven't got a lot
of CPU to spare.

The C News suite of date routines includes support for date
rewriting.  One could use this in a mail gateway to fix the dates.  Or
use the getabsdate proram as inews does if the gateway is a shell
script.  Another possibility is to modify relaynews to use
prsabsdate() and then synthesize a new date header if getindate()
fails. (B News emulation, more or less) Given Geoff and Henry's strong
belief in not rewriting headers, the last is unlikely to happen in the
official C News distribution.

	Mark.
---
"With netnews, *everything* eventually becomes a performance problem!"
	- Geoff Collyer