How do I elegantly print the date in RFC822 format in Perl?

perl datetime date rfc822

11,057

Solution 1

use POSIX qw(strftime);
print strftime("%a, %d %b %Y %H:%M:%S %z", localtime(time())) . "\n";

Solution 2

The DateTime suite gives you a number of different ways, e.g.:

use DateTime;
print DateTime->now()->strftime("%a, %d %b %Y %H:%M:%S %z");

use DateTime::Format::Mail;
print DateTime::Format::Mail->format_datetime( DateTime->now() );

print DateTime->now( formatter => DateTime::Format::Mail->new() );

Update: to give time for some particular timezone, add a time_zone argument to now():

DateTime->now( time_zone => $ENV{'TZ'}, ... )

Solution 3

It can be done with strftime, but its %a (day) and %b (month) are expressed in the language of the current locale.

From man strftime:

%a The abbreviated weekday name according to the current locale.
%b The abbreviated month name according to the current locale.

The Date field in mail must use only these names (from rfc2822 DATE AND TIME SPECIFICATION):

day         =  "Mon"  / "Tue" /  "Wed"  / "Thu" /  "Fri"  / "Sat" /  "Sun"

month       =  "Jan"  /  "Feb" /  "Mar"  /  "Apr" /  "May"  /  "Jun" /
               "Jul"  /  "Aug" /  "Sep"  /  "Oct" /  "Nov"  /  "Dec"

Therefore portable code should switch to the C locale:

use POSIX qw(strftime locale_h);

my $old_locale = setlocale(LC_TIME, "C");
my $date_rfc822 = strftime("%a, %d %b %Y %H:%M:%S %z", localtime(time()));
setlocale(LC_TIME, $old_locale);

print "$date_rfc822\n";

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