- From: Julian Reschke <julian.reschke@gmx.de>
- Date: Sun, 17 May 2009 13:56:48 +0200
- To: "Martin J. Dürst" <duerst@it.aoyama.ac.jp>
- CC: Brian Smith <brian@briansmith.org>, 'Geoffrey Sneddon' <foolistbar@googlemail.com>, 'HTTP Working Group' <ietf-http-wg@w3.org>
Julian Reschke wrote: > Martin J. Dürst wrote: >> That seems to be backward. Wouldn't the comments be helpful in the >> collected ABNF, too? > > The collected ABNF is produced by an ABNF parser (Bill Fenner's), by > serializing the rule objects it generates. Thus, it doesn't have the > comments anymore. > ... In the meantime I noticed that BAP (Bill Fenner's ABNF Parser) can automatically generate comments for printable byte sequences; with that feature turned on the generated ABNF is readable enough without the extra productions. See <http://trac.tools.ietf.org/wg/httpbis/trac/changeset/582>. The section now reads: -- snip -- 3.2. Date/Time Formats: Full Date HTTP applications have historically allowed three different formats for the representation of date/time stamps: Sun, 06 Nov 1994 08:49:37 GMT ; RFC 1123 Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format The first format is preferred as an Internet standard and represents a fixed-length subset of that defined by [RFC1123]. The other formats are described here only for compatibility with obsolete implementations. HTTP/1.1 clients and servers that parse the date value MUST accept all three formats (for compatibility with HTTP/1.0), though they MUST only generate the RFC 1123 format for representing HTTP-date values in header fields. See Appendix A for further information. All HTTP date/time stamps MUST be represented in Greenwich Mean Time (GMT), without exception. For the purposes of HTTP, GMT is exactly equal to UTC (Coordinated Universal Time). This is indicated in the first two formats by the inclusion of "GMT" as the three-letter abbreviation for time zone, and MUST be assumed when reading the asctime format. HTTP-date is case sensitive and MUST NOT include additional whitespace beyond that specifically included as SP in the grammar. HTTP-date = rfc1123-date / obs-date Preferred format: rfc1123-date = day-name "," SP date1 SP time-of-day SP GMT day-name = %x4D.6F.6E ; "Mon", case-sensitive / %x54.75.65 ; "Tue", case-sensitive / %x57.65.64 ; "Wed", case-sensitive / %x54.68.75 ; "Thu", case-sensitive / %x46.72.69 ; "Fri", case-sensitive / %x53.61.74 ; "Sat", case-sensitive / %x53.75.6E ; "Sun", case-sensitive date1 = day SP month SP year ; e.g., 02 Jun 1982 day = 2DIGIT month = %x4A.61.6E ; "Jan", case-sensitive / %x46.65.62 ; "Feb", case-sensitive / %x4D.61.72 ; "Mar", case-sensitive / %x41.70.72 ; "Apr", case-sensitive / %x4D.61.79 ; "May", case-sensitive / %x4A.75.6E ; "Jun", case-sensitive / %x4A.75.6C ; "Jul", case-sensitive / %x41.75.67 ; "Aug", case-sensitive / %x53.65.70 ; "Sep", case-sensitive / %x4F.63.74 ; "Oct", case-sensitive / %x4E.6F.76 ; "Nov", case-sensitive / %x44.65.63 ; "Dec", case-sensitive year = 4DIGIT GMT = %x47.4D.54 ; "GMT", case-sensitive time-of-day = hour ":" minute ":" second ; 00:00:00 - 23:59:59 hour = 2DIGIT minute = 2DIGIT second = 2DIGIT The semantics of day-name, day, month, year, and time-of-day are the same as those defined in the RFC 5322 constructs with the corresponding name ([RFC5322], Section 3.3). Obsolete formats: obs-date = rfc850-date / asctime-date rfc850-date = day-name-l "," SP date2 SP time-of-day SP GMT date2 = day "-" month "-" 2DIGIT ; day-month-year (e.g., 02-Jun-82) day-name-l = %x4D.6F.6E.64.61.79 ; "Monday", case-sensitive / %x54.75.65.73.64.61.79 ; "Tuesday", case-sensitive / %x57.65.64.6E.65.73.64.61.79 ; "Wednesday", case-sensitive / %x54.68.75.72.73.64.61.79 ; "Thursday", case-sensitive / %x46.72.69.64.61.79 ; "Friday", case-sensitive / %x53.61.74.75.72.64.61.79 ; "Saturday", case-sensitive / %x53.75.6E.64.61.79 ; "Sunday", case-sensitive asctime-date = day-name SP date3 SP time-of-day SP year date3 = month SP ( 2DIGIT / ( SP 1DIGIT )) ; month day (e.g., Jun 2) Note: Recipients of date values are encouraged to be robust in accepting date values that may have been sent by non-HTTP applications, as is sometimes the case when retrieving or posting messages via proxies/gateways to SMTP or NNTP. Note: HTTP requirements for the date/time stamp format apply only to their usage within the protocol stream. Clients and servers are not required to use these formats for user presentation, request logging, etc. -- snip -- BR, Julian
Received on Sunday, 17 May 2009 11:57:45 UTC