use Perl

• POSIX character class? (Score:2)

  by djberg96 (2603)

  I sat in a Perl Script Security talk, noting that /^[a-z]+$/ on the slides would erroneously match foo\n

  Is using [:lower:] the appropriate approach? Just curious.
  • Re:POSIX character class? (Score:1)

    by gav (2710) on 2002.07.26 20:54 (#11108) Homepage Journal

    The correct thing is to use \z:

    $_ = "blah\n";
    print "dollar\n" if /^[a-z]+$/;
    print "z\n" if /^[a-z]+\z/;
    __END__
    dollar

    I don't quite like the \a or \z modifiers. They seem a bit funky to me.

    I tend to solve this problem by getting rid of leading and trailing whitespace with something like:

    my %params = map { $_ => trim($cgi->param($_)) } qw(var_a var_b var_c);
    
    sub trim {
      my $str = shift;
      if ($str) {
         $str =~ s/^\s+//;
         $str =~ s/\s+$//;
      }
      $str;
    }

    This also means the user doesn't get tripped up by an extra space at the end of their username etc.

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    • Re:POSIX character class? (Score:3, Informative)

      by TorgoX (1933)

      \a is alarm. You mean \A. Yet another problem with the whole mess!