anti leech CGI

I needed a quick script to provide 'Anti-Leeching' for some of my files. (Leeching is a method of stealing someone else's bandwidth by linking to their files instead of downloading the files to your own site.)

After several iterations, I finally have something that works pretty well for my .zip files.

Just put the hostname and the IP in the @HOSTS array for all your hosts that will use this script. As merlyn mentioned in one of his articles, everyone has a drawer where they keep miscellaneous items, this one belongs in your virtual drawer for that time when you need a quick anti-leech sub.

--
hiseldl
What time is it? It's Camel Time!

Update: changed grep pattern because of merlyn's comment about reverse DNS. Thanks merlyn!

#!/usr/bin/perl -w

use strict;
use CGI qw/:standard/;
$|=1;

my $DIR  = param('d') || './';       # default dir
my $FILE = param('f') || 'xyz.zip';  # default file

my @HOSTS = (
'www.myotherhost.com',
'10.0.0.2',
'www.myhost.com',
'10.0.0.1',
);


print header('text/plain'), "No access to $FILE" 
  unless DownloadFile($DIR, $FILE, \@HOSTS);

exit 0;

sub DownloadFile 
{
    my ($dir, $filename, $hosts) = @_;

    my $remote = remote_host();

    #### the following is bad because it is not an exact
    #### match nor is it anchored
    #### return(0) unless grep /$remote/, @$hosts;

    # the following suggested by [merlyn]
    return 0 unless grep $remote eq $_, @$hosts;

    my $filesize = -s "$dir/$filename";

    # print full header
    print "Content-disposition: filename=$filename\n";
    print "Content-Length: $filesize\n";
    print "Content-Type: application/octet-stream\n\n";

    # open in binmode
    open(READ,$filename) || die;
    binmode READ;

    # stream it out
    binmode STDOUT;
    while (<READ>) { print;    }
    close(READ);

    # should always return true
    return(1);
}
[download]

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