rfc2822 clarification on date headers 2004-01-20 - By Donie Kelly
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Sorry guys, this was supposed to go to the JavaMail mailing list. Sorry.
-- --Original Message-- --
From: Donie Kelly [mailto:donie.kelly@(protected)]
Sent: 20 January 2004 12:15
To: Tomcat Users List (E-mail)
Subject: rfc2822 clarification on date headers
Hi all
Javamail generates a date in the format: Date: Tue, 20 Jan 2004 11:57:37
+0000 (GMT)
The spec below implies that the timezone is either a numeric offset or the
timezone is specified like Date: Fri, 23 Jan 2004 11:57:24 GMT
Can somebody clarify why javamail uses both forms?
Extract from rfc2822 below
Thanks
Donie
3.3. Date and Time Specification
Date and time occur in several header fields. This section specifies
the syntax for a full date and time specification. Though folding
white space is permitted throughout the date-time specification, it
is RECOMMENDED that a single space be used in each place that FWS
appears (whether it is required or optional); some older
implementations may not interpret other occurrences of folding white
space correctly.
date-time = [ day-of-week "," ] date FWS time [CFWS]
day-of-week = ([FWS] day-name) / obs-day-of-week
day-name = "Mon" / "Tue" / "Wed" / "Thu" /
"Fri" / "Sat" / "Sun"
date = day month year
year = 4*DIGIT / obs-year
month = (FWS month-name FWS) / obs-month
month-name = "Jan" / "Feb" / "Mar" / "Apr" /
"May" / "Jun" / "Jul" / "Aug" /
"Sep" / "Oct" / "Nov" / "Dec"
day = ([FWS] 1*2DIGIT) / obs-day
time = time-of-day FWS zone
time-of-day = hour ":" minute [ ":" second ]
hour = 2DIGIT / obs-hour
minute = 2DIGIT / obs-minute
second = 2DIGIT / obs-second
zone = (( "+" / "-" ) 4DIGIT) / obs-zone
The day is the numeric day of the month. The year is any numeric
year 1900 or later.
The time-of-day specifies the number of hours, minutes, and
optionally seconds since midnight of the date indicated.
The date and time-of-day SHOULD express local time.
The zone specifies the offset from Coordinated Universal Time (UTC,
formerly referred to as "Greenwich Mean Time") that the date and
time-of-day represent. The "+" or "-" indicates whether the
time-of-day is ahead of (i.e., east of) or behind (i.e., west of)
Universal Time. The first two digits indicate the number of hours
difference from Universal Time, and the last two digits indicate the
number of minutes difference from Universal Time. (Hence, +hhmm
means +(hh * 60 + mm) minutes, and -hhmm means -(hh * 60 + mm)
minutes). The form "+0000" SHOULD be used to indicate a time zone at
Universal Time. Though "-0000" also indicates Universal Time, it is
used to indicate that the time was generated on a system that may be
in a local time zone other than Universal Time and therefore
indicates that the date-time contains no information about the local
time zone.
A date-time specification MUST be semantically valid. That is, the
day-of-the-week (if included) MUST be the day implied by the date,
the numeric day-of-month MUST be between 1 and the number of days
allowed for the specified month (in the specified year), the
time-of-day MUST be in the range 00:00:00 through 23:59:60 (the
number of seconds allowing for a leap second; see [STD12]), and the
zone MUST be within the range -9959 through +9959.
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