Re: HTTP date format: RFC 850 or RFC 1036

Roy T. Fielding (fielding@simplon.ics.uci.edu)
Wed, 15 Dec 1993 15:09:14 -0800


>> Does anyone implement Date (or Last-Modified) response headers yet?
>> I do, and for now I am going with the new RFC.
> Both Plexus and the NCSA HTTPD (v1.0) use RFC850 style dates:
> Last-modified: Monday, 06-Dec-93 23:48:09 GMT
>
> Changing this for no reason is a bad idea. We should specify the date
> format in the HTTP RFC by value instead of by reference.
>
> If we change this then browsers will have to support both formats forever.

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.
RFC 850 was obsolete long ago. I sent the following to httpd@ncsa
when httpd_1.0 came out, but I'm not sure if it got there because my
mail server went down at the same time. Anyways, here is THE format:

5. DATE AND TIME SPECIFICATION

5.1. SYNTAX

date-time = [ day "," ] date time ; dd mm yy
; hh:mm:ss zzz

day = "Mon" / "Tue" / "Wed" / "Thu"
/ "Fri" / "Sat" / "Sun"

date = 1*2DIGIT month 2DIGIT ; day month year
; e.g. 20 Jun 82

month = "Jan" / "Feb" / "Mar" / "Apr"
/ "May" / "Jun" / "Jul" / "Aug"
/ "Sep" / "Oct" / "Nov" / "Dec"

time = hour zone ; ANSI and Military

hour = 2DIGIT ":" 2DIGIT [":" 2DIGIT]
; 00:00:00 - 23:59:59

zone = "GMT" ; Universal Time

whereas the output from httpd_1.0 is like:

----------------------------------------------------------
% telnet www.ics.uci.edu 80
Trying 128.195.13.1 ...
Connected to www.ics.uci.edu.
Escape character is '^]'.
HEAD /ICShome.html HTTP/1.0

HTTP/1.0 200 OK
Date: Monday, 13-Dec-93 12:12:33 GMT
Server: NCSA/1.0
MIME-version: 1.0
Content-type: text/html
Last-modified: Thursday, 09-Dec-93 16:20:08 GMT
Content-length: 1817

Connection closed by foreign host.
----------------------------------------------------------

which matches the RFC850 example but does not match the
format required by netnews and mail. To be a conformant
arpanet message, the output should be:

----------------------------------------------------------
% telnet www.ics.uci.edu 80
Trying 128.195.13.1 ...
Connected to www.ics.uci.edu.
Escape character is '^]'.
HEAD /ICShome.html HTTP/1.0

HTTP/1.0 200 OK
Date: Mon, 13 Dec 93 12:12:33 GMT
Server: NCSA/1.0
MIME-version: 1.0
Content-type: text/html
Last-modified: Thu, 9 Dec 93 16:20:08 GMT
Content-length: 1817

Connection closed by foreign host.
----------------------------------------------------------

....Roy Fielding ICS Grad Student, University of California, Irvine USA
(fielding@ics.uci.edu)