# Blosxom Plugin: urlshorter
# Author(s): Kyo Nagashima <kyo@hail2u.net>, http://hail2u.net/
# Version: 2009-04-15
# Documentation: See the bottom of this file or type: perldoc urlshorter

package urlshorter;

use strict;
use vars qw($link_element);

# --- Configurable variables -----------

# Do you want to use rel="shorter" instead of rev="canonical"?
my $use_rel = 0;

# Do you want to output as XHTML?
my $as_xhtml = 1;

# --- Plug-in package variables --------

my $attr  = $use_rel  ? 'rel="shorturl"' : 'rev="canonical"';
my $xhtml = $as_xhtml ? ' /' : '';

my @file_info;

# --------------------------------------

sub start {
  return 1;
}


sub filter {
  my($pkg, $files_ref) = @_;

  @file_info = sort {$files_ref->{$a} <=> $files_ref->{$b}} keys %$files_ref;

  return 1;
}

sub skip {
  my $path = $blosxom::path_info;

  # redirect to canonical URL
  if ($path =~ m!^p$!) {
    my $index = $blosxom::path_info_yr;

    if ($path = $file_info[$index]) {
      $path =~ s/^$blosxom::datadir//;
      $path =~ s/\..+?$/.$blosxom::default_flavour/;
      $blosxom::header->{-status} = '301 Moved Permanently';
      $blosxom::header->{-Location} = "$blosxom::url$path";
      $blosxom::output = '';
      # skip! skip! skip!
      return 1;
    }
  }

  return 0;
}

sub head {
  my($pkg, $path, $head_ref) = @_;

  # generate shortened URL only if individual page
  if ($path =~ s/\.$blosxom::flavour$/\.$blosxom::file_extension/) {
    my %path2idx = map { $file_info[$_] => $_ } 0..$#file_info;
    my $index = $path2idx{"$blosxom::datadir/$path"};
    # create link element for specifying shotened URL
    $link_element = qq!<link $attr href="$blosxom::url/p/$index"$xhtml>!;
    # output Link HTTP header
    $blosxom::header->{-Link} = "<$blosxom::url/p/$index>; $attr";
  }

  return 1;
}

1;

__END__

=head1 NAME

Blosxom Plug-in: urlshorter

=head1 SYNOPSIS

provide URL shortening ability and template component for shortened URL to your "lovely" blosxom.

=head1 VERSION

2009-04-13

=head1 AUTHOR

Kyo Nagashima <kyo@hail2u.net>, http://hail2u.net/

=head1 INSTALLATION

Drop urlshorter into your plugins directory, and put a code below to head.html:

$urlshorter::link_element

=head1 SEE ALSO

=over

=item Blosxom Home/Docs/Licensing

http://www.blosxom.com/

=item Blosxom Plugin Docs

http://www.blosxom.com/documentation/users/plugins.html

=back

=head1 BUGS

Address bug reports and comments to:

=over

=item blosxom ML

http://groups.yahoo.com/group/blosxom/

=item all about blosxom ML

http://www.freeml.com/info/blosxom@freeml.com

=back

all about blosxom ML: http://www.freeml.com/info/blosxom@freeml.com

=head1 LICENSE

Copyright 2009, Kyo Nagashima <kyo@hail2u.net>, http://hail2u.net/

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.