CREATE OR REPLACE FUNCTION inventory.sha1_to_url( IN sha1 text, IN url_base text, IN content_type text, OUT text ) AS $$
  use URI;
  my ( $sha1, $url, $ct ) = @_;

  my ( $d1, $d2, $xs ) = unpack "A2A2A*", $sha1;
  $url =~ /.*([.].+)$/;
  my $ext = $1;

  my $u = URI->new( $url );
  my $ext = 'jpg' if $ct =~ /jpe?g/;
  $u->path_segments( (split '/', $u->path), $d1, $d2, "$xs\.$ext" );

  return $u->canonical;
$$ LANGUAGE plperlu STRICT IMMUTABLE;