Re: HTTP date format: RFC 850 or RFC 1036

Tony Sanders <sanders@bsdi.com>
Errors-To: sanders@bsdi.com
Errors-To: sanders@bsdi.com
Message-id: <199312160130.TAA09527@austin.BSDI.COM>
To: "Roy T. Fielding" <fielding@simplon.ics.uci.edu>
Cc: www-talk@nxoc01.cern.ch, Tim Berners-Lee <timbl@www0.cern.ch>
Subject: Re: HTTP date format: RFC 850 or RFC 1036 
In-Reply-To: "Roy T. Fielding"'s message of Wed, 15 Dec 1993 15:09:14 PST.
Errors-To: sanders@bsdi.com
Reply-To: www-talk@nxoc01.cern.ch
Organization: Berkeley Software Design, Inc.
Date: Wed, 15 Dec 1993 19:30:39 -0600
From: Tony Sanders <sanders@bsdi.com>

> NO NO NO NO!!!!!!
> 
> The date format MUST be RFC822 compliant (as is the new RFC1036) and
> can be seen in every Date: field generated by NNTP and mail.
Is that so... Hmmm... a quick sample (from comp.mail.headers!) reveals no
less than six (6) different Date formats in current use:
    Date: 1 Dec 1993 15:40:28 -0000
    Date: 15 Dec 1993 18:00:37 GMT
    Date: 4 Dec 93 23:53:10 GMT
    Date: Tue, 14 Dec 1993 21:29:02 GMT
    Date: Wed, 8 Dec 93 07:51:39 GMT
    Date: Mon, 06 Dec 93 22:05:22 +1000 (AEST)
And this is from a sample size of only 7 messages!

In other groups I found some really amazing stuff:
    Date: Monday 13 April, 1992 09:30:00 PDT
    Date: Monday, March 3, 12:59:00 CDT
    Date: Monday May 24 23:01:34.34 CDT 1993
    Date: Thu, 2 Dec 1993 12:53:49
    Date: Wed, 15 Dec 1993 13:36:54 UNDEFINED
I have just as many email examples also.  So much for "MUST" and "every".

Guess what else.  Every RFC850-like date format I could find was consistent!
    Date: Friday, 24-Sep-93 20:38:06 GMT
If you had a full dayname or you had hypens between the date section
you had a valid RFC850 date.  Amazing (even to me).

Now, do you have any valid arguments for *why* we should break hundreds
of HTTP servers?  It is VERY VERY important that HTTP software agree on
the date format, and that it not change weekly.  This isn't so with News
and Mail (as is obvious by the lack of a real standard in those cases).

Clearly having a full year (instead of just two digits) is not optimial
but neither is it a major problem (not until 2070 or so anyway).

If we do end up changing then this is clearly the best format:
    Date: Tue, 04 Dec 1993 21:29:02 GMT

--sanders