converting to my time given Mail Date

Posted on 1998-08-13
Medium Priority
Last Modified: 2010-03-05
I need to be able to convert a date as shown by RFC822 (mail headers), to my localtime. I am working in Perl 5.

Say the input is:

"Wed, 12 Aug 1998 13:13:58 -0400"

I want the output to be:

Wed, 12 Aug 1998 13:13:58

but if the input is:

"Wed, 12 Aug 1998 13:13:58 -0300"

I want the output to be:

Wed, 12 Aug 1998 12:13:58

and be able to handle all the different timezones. I looked at GNUs and they don't do it, they just put the date as it comes with GMT, +0100, -0500. I would like to be able to convert the time to my local time.

anybody knows how I can do this in Perl?

BTW, I'm in Montreal, so I am -0400. I looked in tin code and they have a 400-line parser (yacc) to do this. Is there a way to do it in Perl. I have a function already that gives me the -0400 so take that as a given as well.
Question by:agj
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Expert Comment

ID: 1209257
I don't think you meant to submit this question twice, you should be able to delete it.

Accepted Solution

kaijen earned 1200 total points
ID: 1209258
Let's try:

$date = "Wed, 12 Aug 1998 13:13:58";
$date =~ m#(\w+,\s+\d+\s+\w+\s+\d+\s+)(\d+):(\d+):(\d+)(?:\s+(\+|-)?(\d{2}))?#;

$begin = $1;
$hour = $2;
$min = $3;
$sec = $4;
$sign = $5;
$diff = $6 if $6 ne "";
$diff = 0 if $6 eq "";

if ( $sign eq "-" )
      $hour += $diff - 4;
      $hour -= $diff + 4;

$date = "$begin$hour:$min:$sec";

print "$date\n";

should do the job.

Best regards,

Expert Comment

ID: 1209259
Kai, what if the add or subtract of the hours takes you past midnight?
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Expert Comment

ID: 1209260
Well, it's too late to delete it now without help from customer support now that kaijen has locked it.
But what if the input is
"Wed, 12 Aug 1998 01:13:58 -0100"

Expert Comment

ID: 1209261
Okay, you're right! Sorry for beeing so fast. I think the idea is clear and there's a lot more work to invest to consider midnight, month changing and new years day. If anyone has a shorthand solution for this please reject my answer and I volunteer for accepting this.


Best regards,

Expert Comment

ID: 1209262
Actually, agj accidentally submitted the question twice (it's actually easier to do than it should be.  The question has already been answered (basically, the answer was to use the Date::Manip package)

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