New plugin: head_meta-v0.1b

To use the expression, I had an itch that needed scratching.  I 
couldn't find any existing bloxsom plugins to do what I needed, so I wrote 
something.  If I've reinvented some wagon wheel I didn't know 
about, I'd appreciate a pointer to something better.

My first working version of head_meta determines the meta tags for 
the top story on the page (using the meta plugin), and caches them so 
that they can be used in the head and foot templates.  The goal was 
to be able to have unique keywords and page description meta tags in the
head section of the html for each  story.  This is valuable for many
search engine optimization strategies.

This plugin seems to be working OK now on my site at: http://www.wildebeat.net/

I had to rename the meta plugin to "0meta" so that it would load 
before head-meta.  I know there's a better way to do this, but I 
don't know what that is.

I've pasted the code into this e-mail, below.  As you'll see, it
really doesn't have any documentation yet.  Once I've done some more
testing (and if I get any feedback), I'll create another version and
make it available on my web site.

-----SNIP-----
# Blosxom Plugin: head_meta
# Author(s):  Steve Sergeant <stevesgt@...>
# Version: 0.1b of 20080722
# Blosxom Home/Docs/Licensing: http://www.raelity.org/apps/blosxom/
# Blosxom Plugin Docs: http://www.raelity.org/apps/blosxom/plugin.shtml

# Copyright 2008 Steve Sergeant
# Released under the same License as Blosxom

package head_meta;

# --- Configurable variables -----

# location of the cache file
my $DataFile = $blosxom::plugin_state_dir.'/'."head_meta.dat";

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

my $read_story = 0; 
my $cachedmetadata = {};
my ($page_key, $cached_title) = ('','');

sub load_meta {
    my $metadata = {};
    my $url;
    #open data file
    local *FH;
    if( -e "$DataFile") {
		open FH, "$DataFile" or return $metadata;
    }
	flock(FH, 2);
	while (<FH>) {
		chomp ($_);
		my @meta_items = split(m!\t!) ;
		$url = shift(@meta_items);
		foreach (@meta_items) {
			my ($name, $value) = m/^([^=]+)="([^"]*)"$/;
			$metadata->{$url}{$name} = $value;
		}
    }
    close (FH);
    return $metadata;
}

sub save_meta {
    my $metadata = shift;
    my $url = '' ;
    local *FH;
    open FH, ">$DataFile" or return 0;
    flock(FH, 2);
    foreach $url (keys(%{$metadata})) {
    	my $name = '';
	    my @meta_items = ($url) ;
    	foreach $name (keys(%{$metadata->{$url}})) {
    		push @meta_items, ($name.'="'.$metadata->{$url}{$name}.'"');
    	}
		print FH join("\t",@meta_items)."\n"; 
    }
    close FH;
    return 1;
}

sub start {
	my $key = '' ;
     if ($blosxom::path_info_yr ) {
     	my @date_items ;
		foreach ($blosxom::path_info_yr, $blosxom::path_info_mo, $blosxom::path_info_da)
    		{ if ($_) {push @date_items, $_ }}
        $page_key = join('/',@date_items);
	} else {
		$page_key = $blosxom::path_info;
    }

    if ($ENV{"QUERY_STRING"}) {
	$page_key .= '?'.$ENV{"QUERY_STRING"};
    }
    $cachedmetadata = load_meta();

    $cached_title = $cachedmetadata->{$page_key}{'title'};

    $$_ = undef foreach @keys;
	@keys = ();
	foreach $key (keys(%{$cachedmetadata->{$page_key}})) {
    	($cachedmetadata->{$page_key}{$key} ne 'title') and push(@keys,$key) and $$key =
$cachedmetadata->{$page_key}{$key} ;
    }

    1;
} # end sub start

sub story {
	my($pkg, $path, $filename, $story_ref, $title_ref, $body_ref) = @_;
	my $name = '';
	if (!$read_story) {
		if (!$cached_title || $cached_title ne $$title_ref) {
			$cachedmetadata->{$page_key}{'title'} = $$title_ref;
			foreach $name ( keys %meta:: ) {
				$cachedmetadata->{$page_key}{$name} = ${$meta::{$name}} if (${$meta::{$name}});
			}
			save_meta($cachedmetadata);
		}
		$read_story = 1;
    }	
    1;
} # end sub story

1;

=head1 NAME

Blosxom Plug-in: head_meta

=head1 SYNOPSIS

Capture meta values from top-most story for use in the head and foot templates.

=head1 VERSION HISTORY

=head2 Version 0.1

Jul 22, 2008:  It works, basically.

=head1 LICENSE

Blosxom and this Blosxom Plug-in
Copyright 2003, Rael Dornfest 

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.

=cut

__END__

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