How can I validate a "yyyy-MM-dd'T'HH:mm:ssZ" date/timestamp in UTC with Perl?

Question

Code would be nice but a point in the right direction is good as well.

CPAN? RegEx?

I've seen both ways

"yyyy-MM-dd'T'HH:mm:ssZ";

"yyyy-MM-ddTHH:mm:ssZ";

Answer 1

Use both. Use a RegEx to split the input string into individual components (Year, Month, Day, etc...) then use Date::Calc http://search.cpan.org/~stbey/Date-Calc-6.3/lib/Date/Calc.pod

(I don't know what the 'T' and the 'Z' in "yyyy-MM-dd'T'HH:mm:ssZ" means so I'm very casually ignoring it ;)

if( $inStr =~ /(\d\d\d\d)-(\d{1,2})-(\d{1,2}) (\d{1,2})\:(\d\d)\:(\d\d)/ ) {
    $year = $1;
    $month = $2;
    $day = $3;
    $hour = $4;
    $min = $5;
    $sec = $6;
    if (check_date($year,$month,$day) && check_time($hour,$min,$sec)) {
        # looks good to me!
    }
}

Answer 2

Depending on what you're doing, you might want to coerce your string into a DateTime object, e.g.:

use DateTime::Format::MySQL;
my $dt = DateTime::Format::MySQL->parse_datetime( '2003-01-16 23:12:01' );

Then you can easily output your time string in a different format, perform calculations with it, etc.

You didn't specify what is generating the string in that particular format, but there are DateTime::Format:: modules for a large number of input sources.

Answer 3

Ether is definitely on the right track with DateTime. Using DateTime, you can be sure that you have a time that actually exists, where something on Feb 29, 2000 might get by if you wrote the checks yourself.

Your format looks like an ISO8601 string. So, use DateTime::Format::ISO8601 to do your parsing.

use DateTime;
use DateTime::Format::ISO8601;

my $string = '2010-02-28T15:21:33Z';

my $dt = DateTime::Format::ISO8601->parse_datetime( $string );
die "Impossible time" unless $dt;

You could use other format modules, such as D::F::Strptime, but you will wind up recreating what ISO8601 formatter already does.