HTTP Pocket Reference

Name

Date: dateformat

Synopsis

There are three formats that can be used to express the date. The preferred date format is RFC 1123. For example:

Mon, 06 May 1996 04:57:00 GMT

The preferred RFC 1123 format specifies all dates in a fixed length string in Greenwich Mean Time (GMT). GMT is always used in HTTP to prevent any misunderstandings among computers communicating in different time zones. The valid days are: Mon, Tue, Wed, Thu, Fri, Sat, and Sun. The months are: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, and Dec.

For backwards compatibility, the RFC 1036 and ANSI C asctime ( ) formats are also acceptable, but not recommended:

Monday, 06-May-96 04:57:00 GMT

Mon May 6 04:57:00 1996

The RFC 1036 format is similar to the one in RFC 1123, except that the string length varies, depending on the day of the week, and the year is specified in two digits instead of four. This makes date parsing more difficult. The valid days are: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday. The months are: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, and Dec.

ANSI C’s asctime ( ) format is not encouraged, since there can be misunderstandings about the time zone used by the computer. The valid days are: Mon, Tue, Wed, Thu, Fri, Sat, and Sun. The months are: Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, and Dec.

Despite a heavy preference for RFC 1123’s format, current web clients and servers should be able to recognize all three formats. However, when designing web ...