At the Forge - Blosxom

Listing 1 contains a simple filter, called egotrip, to make my name appear in boldface whenever it appears in a Weblog entry. Notice how the plugin must define its own package; this ensures that each plugin's subroutines are kept in a separate namespace and makes it possible for Blosxom to determine whether a package contains a particular method name.

#!/usr/bin/perl

use strict;
use warnings;
use diagnostics;

package egotrip;

# Returns 1 to indicate the plugin is active
sub start
{
    return 1;
}

# Boldfaces my name
sub story {
    my ($pkg, $path, $filename, $story_ref,
        $title_ref, $body_ref) = @_;

    $$body_ref =~ s|Reuven|<b>Reuven</b>|g;
    1;
}

1;

The actual work is done in the story subroutine, which is passed six arguments when invoked by Blosxom, corresponding to a number of items having to do with the entry. In our case, we care about changing only the body of the entry, which is in the final variable, known as $body_ref. As its name implies, this is a scalar reference, which means we can access or modify its contents by dereferencing it, using two $$ signs. With that in mind, it should not come as a surprise that we can boldface every instance of my name with:

$$body_ref =~ s|Reuven|<b>Reuven</b>|g;

Of course, we could make this step even more sophisticated and insert automatic hyperlinks to a number of different items:

$$body_ref =~ s|(Reuven Lerner)|
↪<a href="http://www.lerner.co.il/">$1</a>|g;
$$body_ref =~ s|(Linux Journal)|
↪<a href="http://www.linuxjournal.com/">$1</a>|g;

Indeed, a plugin of this sort already exists; it automatically creates links to the community-driven Wikipedia. Any text placed within [[brackets]] automatically is turned into a link to that on-line reference book.

Notice how flavours are HTML templates into which we can instantiate Perl variable values, whereas plugins are Perl programs. This division between display and actions takes a little bit of time to grasp, but it shouldn't be too difficult.

As for our paragraph-separating problem from before, there's no need to reinvent the wheel. You simply can download a plugin, Blox, that allows you to separate paragraphs with blank lines when writing your blog entry. The plugin then separates paragraphs with the HTML of your choice. Blox is listed on Blosxom's plugin registry (see the on-line Resources section).

The fact that Blosxom keeps all entries and flavours in a single directory is a bit disturbing to me and makes me wonder about the program's scalability. Even if my filesystem and Perl can handle that many files without too much trouble, do I really want to wade through them all? If and when this becomes a problem, an entries plugin probably can provide the right solution, scooping up files from multiple directories and returning an appropriate hash to Blosxom.

Blosxom is a powerful tool for creating a Weblog; it's more than it might appear at first glance. Blosxom consists of an easy-to-install, easy-to-configure CGI program written in Perl, but its true power lies in the fact that it lets you change every part of the display through a combination of flavours (display templates) and plugin routines. By mixing and matching existing flavours and templates with something of your own, it can be easy to create your own Weblog.

Resources for this article: /article/7454.