slok has asked for the wisdom of the Perl Monks concerning the following question: 

I am using the CGI module.

In my perl script, I take in a "year" field from the form.

1. How can I check that this is a valid year?
ie not greater than current year?

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2006-03-21 Retitled by planetscape, as per Monastery guidelines
Original title: 'date question'

Replies are listed 'Best First'.
Re: How to validate the year of a date?
by gmax (Abbot) on May 09, 2002 at 06:46 UTC
    You can get the current year using localtime, and then compare it to the form field.
    Before comparing, though, you should check that the year field is numeric.
    my $yearfield = get_it_from_somewhere();
my $current_year = (localtime)[5] + 1900;
die "invalid number\n" unless $yearfield =~ /^\d+$/;
die "invalid year\n" if $yearfield > $current_year;

    [download]
    See the localtime page for more details.

    HTH
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[d/l]
      The "invalid number" test should probably be a little more picky: 
       ... unless $yearfield =~ /^\d{4}$/;

      [download]
      or maybe the user should be indulged when entering strings like "02", "99", etc, which entails something messier, like: 
       ... unless $yearfield =~ /^(\d{2}){1,2}$/;
 if (length($yearfield) == 2) {
   $millen = ( $yearfield =~ /^0/ ) ? "20" : "19";
   $yearfield = $millen . $yearfield;
 }
 ...

      [download]
      (In this case, naturally, one shouldn't expect this script to still be in use after 2009, nor should users ever want to refer to years in the 19th century -- I have no problem with that.)
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