gistfile1.pl

use Plack::Builder;
use AnyEvent::Feed;
use POSIX qw/ceil/;

my @image_urls;
my $img_re = qr{https?://[^\s]+\.(?:gif|png|jpe?g)}i;

my $feed = AnyEvent::Feed->new(
  url => 'http://cutegirlsbeingcute.tumblr.com/rss',
  interval => 60 * 60, # every hour
  on_fetch => sub {
    my ($reader, $new, $feed, $error) = @_;
    return unless @$new;
    @image_urls = map {($_->content->body =~ /($img_re)/g)} $feed->entries;
  },
);

builder {
  mount "/" => sub {
    my $env = shift;
    my $image = $image_urls[ceil(rand($#image_urls))];
    return [301, [Location => $image], []];
  }
};