My domain name stripper. Takes a Full URL with GET variables, an email address, www.domain.com domain.com address and spits out either fqdn.domain.com or domain.com for use when running under taint mode, depending on the type requested. 

$self->stripper('fqdn', $url); # www.domain.com
$self->stripper('regdn', $url); #domain.com

[download]
Note: This only works for single dot TLDs (.com, .net, .info, .ca, etc) and not intl TLDs like .co.uk etc with multiple dots. 
sub stripper {
        my $type = shift;
        my $url  = shift;
        if ( $url =~
m/((?:(?:https?|ftp|irc):\/\/|(?:(?:(www)|(ftp))[\w-]*\.))?[-\w\/~\@:]
++\.\S+[\w\/])/i
          )
        {
            $url = "$1";
        }
        else {
            &err($url);
        }
        $url =~ s/^https?:\/\/|mailto:|(.*)\@//ig
          ;    # get http(s)://, mailto:, and email@
        $url =~ s/\/.*//;          #Strip out the / and everything aft
+er it
        $url =~ s/[\?\#\:].*//;    # Get any GET vars
        my $fqdn = $url;
        
        my @domain = split( /\./, $url );

        # We have to do this backwards (com.domain.sub)
        my $tld    = pop(@domain);            #.com
        my $secld  = pop(@domain);            #.domain
        my @result = ( $secld, $tld );
        my $regdn  = join( "\.", @result );
        if ( $type eq "fqdn" ) { 
            return $fqdn;
        }
        else {
            return $regdn;
        }
}

[download]

In reply to URL, etc to Domain Name Stripper by jnbek

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