As per advice given to me in Find Ethernet Card Manufacturer, I've created my first real module. My module mirrors a copy of a remote file the location specified in my module's variable $oui_location. I would like the script that uses my module to be able to change that value.

I tried including $oui_location in the @EXPORT_OK array and then doing something like this in the calling script: 

use OUILookup ('get_oui_owner', 'oui_location');
$oui_location = "oui2.txt";

[download]

but it didn't work.

What do I have to do?

package OUILookup;

require Exporter;
use LWP::Simple;

use strict;
use warnings;

our @ISA       = qw(Exporter);
our @EXPORT    = qw(get_oui_owner);
our $VERSION   = 1.00;

my $oui_address = "http://standards.ieee.org/regauth/oui/oui.txt";
my $oui_location = "oui.txt";

sub get_oui_owner {
    my ($mac) = @_;
    my $oui = validate_input($mac);
    my $oui_entry;
    my $foundit = 0;

    if ($oui eq "invalid address format") {
        return $oui;
    }
    else {
        if (update_ouidb()) {
            open(OUI, $oui_location) or die "Unable to locate $oui_loc
+ation: $!\n";
            while (<OUI>) {
                chomp;
                if (/$oui/) {
                    $oui_entry = $_;
                    $foundit = 1;
                    last;
                }
            }
            close(OUI);
            if (!$foundit) {
                return "OUI not found";
            }
            else {
                $oui_entry =~ s/\w{2}-\w{2}-\w{2}|^\w{6}//g;
                $oui_entry =~ s/\(hex\)|\(base 16\)//g;
                $oui_entry =~ s/^\s+//g;
                return $oui_entry;
            }
        }
    }
}

sub update_ouidb {
    my $errcode = mirror("http://standards.ieee.org/regauth/oui/oui.tx
+t", $oui_location);
    if (!($errcode eq "200" || "304")) {
        die "problem updating OUI database: $!\n";
    }
    else {
        return 1;
    }
}

sub validate_input {
    my ($input) = @_;
    my @bytes;
    my $oui;

    if ($input =~ /\w{2}-\w{2}-\w{2}-\w{2}-\w{2}-\w{2}/) {
        @bytes = split '-', $input;
        $oui = join '-', $bytes[0], $bytes[1], $bytes[2];
        return $oui;
    }
    else {
        return "invalid address format";
    }
}

1;

=head1 NAME

OUILookup

=head1 SYNOPSIS

Find the owner of the IEEE Organizationally Unique Identifier (OUI)
for a particular MAC address.

OUILookup uses the IEEE database from <http://standards.ieee.org/regau
+th/oui/oui.txt>.
It will create a local copy of that database if one does not already e
+xist, and update
a the local copy if it does exist. 

By default, the local copy will be stored as oui.txt in the same direc
+tory as the script.
This location is set by the module variable $oui_location.

=head1 USAGE

use OUILookup;

$mac = "00-10-5A-1B-C3-30";

$owner = get_oui_owner($mac);

=head1 REQUIRES

LWP::Simple

=head1 TESTED

Perl 5.6.0 on Windows NT (Service Pack 6)

=head1 AUTHOR

Micah Valine <mvaline@buffnet.net>

=cut

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In reply to Allowing user to change module variables by mvaline

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