SMTP Date format?

[Ben Giddings]

Hey all,

Is there already code which formats a date into the format required for SMTP?

[url]http://ftp.rfc-editor.org/in-notes/rfc2822.txt[/url]

See sec 3.3

I've been writing my own version, but it really seems like it must have
already been done.

Ben

[Tanaka Akira]

In article <200307221635.02170.ben@thingmagic.com>,
Ben Giddings <ben@thingmagic.com> writes:

> Is there already code which formats a date into the format required for SMTP?
>
> [url]http://ftp.rfc-editor.org/in-notes/rfc2822.txt[/url]

time.rb which is bundled since 1.6.7 has Time#rfc2822.

% ruby -rtime -e 'p Time.now.rfc2822'
"Wed, 23 Jul 2003 09:29:05 +0900"
--
Tanaka Akira

[Ben Giddings]

On Wed July 23 2003 9:35 am, Josef 'Jupp' Schugt wrote:

> * Ben Giddings; 2003-07-22, 20:38 UTC:

> > Is there already code which formats a date into the format required
> > for SMTP?

>
> What exactly can strftime not do for you?

Well the tough part was going to be the timezone offset part:

Date: Wed, 23 Jul 2003 22:35:49 +0900
^^^^^

But now that I found the time library which does the formatting I'm set.

While we're on the subject though, what's the recommended method for
determining your timezone offset in Ruby?

Ben

[Brian Candler]

On Thu, Jul 24, 2003 at 01:22:33AM +0900, Josef 'Jupp' Schugt wrote:

> On Thu, 24 Jul 2003, Ben Giddings wrote:
>
>

> > But now that I found the time library which does the formatting I'm
> > set.
> >
> > While we're on the subject though, what's the recommended method
> > for determining your timezone offset in Ruby?

>
> On my system (at home) the only reliable method would be asking the
> user to provide it. The machine is running on UTC while the official
> timezone is MESZ (UTC+2).

But Unix machines, although they "run" on UTC, can be configured with a
local timezone. This is the time you will see when you run the 'date'
command, for example. On most machines I've seen this is set by creating
/etc/localtime as a symlink to /usr/share/zoneinfo/<whatever>; it can also
be overriden by setting environment variable TZ.

In many parts of the world the timezone offset varies throughout the year,
but with a modern implementation of localtime() it will tell you it:

#include <stdio.h>
#include <time.h>
int main(void)
{
time_t now = time(NULL);
struct tm *tm = localtime(&now);
printf("The current timezone name is %s\n",tm->tm_zone);
printf("The current timezone offset is %ld secs from GMT\n",tm->tm_gmtoff);
return 0;
}

When I run this I get:

The current timezone name is BST
The current timezone offset is 3600 secs from GMT

(I am in the UK). So the information is there - whether there's a Ruby
wrapper for it I don't know.

If you're on a Windows machine though, you're in a whole different sorry
state. At work I get E-mails from people using Outlook calendar saying
"meeting scheduled for 14:00 GMT (London, Lisbon, ...)" when in fact they
mean 2pm local time, which in the summer is 13:00 GMT. The clock is actually
moved forwards and backwards when daylight savings starts and ends, instead
of calculating the offset. If you turn your computer on at 1.30am on the day
that the change takes place, your computer has no idea what the correct time
is.

Cheers,

Brian.

[Josef 'Jupp' Schugt]

Saluton!

* Brian Candler; 2003-07-24, 12:25 UTC:

> When I run this I get:
>
> The current timezone name is BST
> The current timezone offset is 3600 secs from GMT

UTC, no offset here. Principle of least trouble.

Gis,

Josef 'Jupp' Schugt
--
N'attribuez jamais à la malice ce que l'incompétence explique !
-- Napoléon

[Brian Candler]

On Fri, Jul 25, 2003 at 04:14:25AM +0900, Trevor Jenkins wrote:

> I don't believe in BST so there's no surprise that all my systems here, in
> London, report:
>
> The current timezone name is GMT
> The current timezone offset is 0 secs from GMT
>
> Which is as it should be.

Well, each to his own. If you're parsing crappy log files that don't store
the time unambiguously, then I agree that local time could be a problem.

Cheers,

Brian.

[Ian M Dew]

Thank you, Tanaka Akira!

With non-rfc2822 date formats, the Android email app displays dates as "12/31/1969" and places emails at the bottom of the inbox.