Re^2: IPv4 regex

I ran into undefined variables while iterating through a multidimensional hash containing all sort of server info using that function. I silenced them with a simple modification (checking if the parts of the IP is "defined"):

sub IP_valid {
my $ip = shift;
    $ip =~/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/;
    foreach ($1,$2,$3,$4){
        if ( defined $_ && $_  <256 && $_ >0) {next;}
        return 0;
    }
    return 1;
}
[download]

Sure, that could have been added earlier but that if test was already checking multiple factors so it was easier to add. Thanks for this simple write-up! Just what I was looking for. Wow, 15 years later.

Comment on Re^2: IPv4 regex Download Code

Replies are listed 'Best First'.
Re^3: IPv4 regex by AnomalousMonk (Archbishop) on Jul 22, 2016 at 20:47 UTC
Please also see Regexp::Common and Regexp::Common::net. c:\@Work\Perl\monks>perl -wMstrict -le "use Test::More 'no_plan'; use Test::NoWarnings; ;; VECTOR: for my $ar_vector ( [ '1.133.123.123', 1 ], [ '1.2.3.4', 1 ], [ '11.22.33.44', 1 ], [ '0.0.0.0', 1 ], [ '255.255.255.255', 1 ], [ '', '' ], [ '1asdf1.133.123.123', '' ], [ '12341.133.', '' ], [ '0.0.0.256', '' ], [ 'not at all valid', '' ], [ '1.2.3.4.5', '' ], [ '1111.2.3.1111', '' ], ) { my ($ip, $valid) = @$ar_vector; ;; my $status = $valid ? 'valid' : 'INVALID'; is IP_valid($ip), $valid, qq{'$ip' $status}; } ;; done_testing; ;; ;; use Regexp::Common qw(net); ;; sub IP_valid { my ($ip) = @_; return $ip =~ m{ \A $RE{net}{IPv4} \z }xms; } " ok 1 - '1.133.123.123' valid ok 2 - '1.2.3.4' valid ok 3 - '11.22.33.44' valid ok 4 - '0.0.0.0' valid ok 5 - '255.255.255.255' valid ok 6 - '' INVALID ok 7 - '1asdf1.133.123.123' INVALID ok 8 - '12341.133.' INVALID ok 9 - '0.0.0.256' INVALID ok 10 - 'not at all valid' INVALID ok 11 - '1.2.3.4.5' INVALID ok 12 - '1111.2.3.1111' INVALID 1..12 ok 13 - no warnings 1..13 [download] Note that, by design, `$RE{net}{IPv4}` is not "anchored", so by itself it will match, e.g.: `c:\@Work\Perl\monks>perl -wMstrict -le "use Regexp::Common qw(net); ;; print qq{matches IP of '$1'} if '99999.1.2.9999' =~ m{ ($RE{net}{IPv4}) }xms; " matches IP of '99.1.2.99'` [download] which may or may not be what you want. The `\A \z` anchors in the example code above address this (quite intentional) feature. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^3: IPv4 regex
by AnomalousMonk (Archbishop) on Jul 22, 2016 at 20:47 UTC

Please also see Regexp::Common and Regexp::Common::net.

c:\@Work\Perl\monks>perl -wMstrict -le
"use Test::More 'no_plan';
 use Test::NoWarnings;
 ;;
 VECTOR:
 for my $ar_vector (
   [ '1.133.123.123', 1 ],  [ '1.2.3.4', 1 ],  [ '11.22.33.44', 1 ],
   [ '0.0.0.0', 1 ],  [ '255.255.255.255', 1 ],
   [ '', '' ],  [ '1asdf1.133.123.123', '' ],  [ '12341.133.', '' ],
   [ '0.0.0.256', '' ],  [ 'not at all valid', '' ],
   [ '1.2.3.4.5', '' ],  [ '1111.2.3.1111', '' ],
   ) {
   my ($ip, $valid) = @$ar_vector;
   ;;
   my $status = $valid ? 'valid' : 'INVALID';
   is IP_valid($ip), $valid, qq{'$ip' $status};
   }
 ;;
 done_testing;
 ;;
 ;;
 use Regexp::Common qw(net);
 ;;
 sub IP_valid {
   my ($ip) = @_;
   return $ip =~ m{ \A $RE{net}{IPv4} \z }xms;
   }
"
ok 1 - '1.133.123.123' valid
ok 2 - '1.2.3.4' valid
ok 3 - '11.22.33.44' valid
ok 4 - '0.0.0.0' valid
ok 5 - '255.255.255.255' valid
ok 6 - '' INVALID
ok 7 - '1asdf1.133.123.123' INVALID
ok 8 - '12341.133.' INVALID
ok 9 - '0.0.0.256' INVALID
ok 10 - 'not at all valid' INVALID
ok 11 - '1.2.3.4.5' INVALID
ok 12 - '1111.2.3.1111' INVALID
1..12
ok 13 - no warnings
1..13
[download]

$RE{net}{IPv4}

c:\@Work\Perl\monks>perl -wMstrict -le
"use Regexp::Common qw(net);
 ;;
 print qq{matches IP of '$1'}
   if '99999.1.2.9999' =~ m{ ($RE{net}{IPv4}) }xms;
"
matches IP of '99.1.2.99'
[download]

\A \z

Give a man a fish: <%-{-{-{-<

[reply]
[d/l]
[select]