The custom stylesheet is based on the standard DocBook XSL XHTML stylesheet. However, instead of inserting an HTML header, it inserts PHP calls to include the WordPress headers and footers. The only tricky part of this is to tell WordPress what the title of the resulting page should be. I hacked this in by creating a class with the bare minimum fields required by wp_title() (which is used by WordPress to print the title of the document). The resulting template looks like this:

<?php
  require('../wordpress/wp-blog-header.php');
  class MyPost { var $post_title = "My Title"; }
  $wp_query->is_home = false;
  $wp_query->is_single = true;
  $wp_query->queried_object = new MyPost();
  get_header();
?>
<div id="content" class="narrowcolumn" role="main">
  ...
</div>
<?php
  get_sidebar();
  get_footer();
?>

The DocBook kit is available from my Git repository (or on GitHub, or as a ZIP file). More information about the kit can be found here.

Starting a DocBook project requires a few elementary tools to be installed:

• The DocBook XML schemas. These are used to validate whether your document is a legal DocBook document.
• The DocBook XSL stylesheets. These are used to transform your DocBook input file into other formats, such as HTML or XSL-FO (a format which can be converted to PDF)
• XML and XSL processing tools. These tools take the schemas and stylesheets mentioned above, and apply them to your document to do the actual checking and transformation. I use xmllint and xsltproc (available out of the box on many platforms and distributions), but other tools can be used as well (e.g. Saxon or Xalan)
• An XSL-FO processor, to transform the intermediate XSL-FO format generated by the stylesheets to PDF. I use the Free Apache FOP, but commercial tools such as RenderX XEP and AntennaHouse are very popular for this too.

Once you have all these tools, you need to tie them all together to be able to get from your DocBook file to your desired output format, such as PDF or HTML. Because this involves quite some boilerplate scripting, I created a DocBook kit to make this as light as possible. The DocBook kit comes with a Makefile, which you can use to do all the work for you. The kit also automatically downloads the DocBook XML schemas and XSL stylesheets, making it possible to start working on a DocBook project on a machine with only some basic tools (xmllint and xsltproc) installed.

To use the kit, simply drop it in the directory of your project, and create a minimal Makefile such as the following one:

# The toplevel DocBook file of our project
DOCUMENT = MyDocument.xml

# Include the DocBook Kit's makefile rules
include docbook-kit/tools/Makefile.inc

This makes several make commands available, such as:

• make, make pdf, make html, make txt: Creates an HTML, PDF, and/or TXT file of your document.
• make check: Validates your document syntactically.
• make check-spelling: Runs a spell checker on your document.
• make package: Creates a flat DocBook file (i.e. one with all the parts included using XIncludes expanded), normalizes all figure names, and packages the result up into a tarball.

The makefile also tracks the dependencies of the document, making sure that your document is rebuilt whenever one of its dependencies (e.g. images, document parts included using XInclude) changes.

Besides tools, the kit also provides a customization layer around the standard XSL stylesheets. These customizations change fonts, spacings, and other presentation parameters for the output document. You can use these as an example on how to make your DocBook document look the way you want. Detailed information on using and customizing the DocBook XSL stylesheets can be found in Bob Stayton’s DocBook XSL: The Complete Guide.

The DocBook kit is available from my Git repository (or on GitHub, or as a ZIP file), and comes with an example of a simple project using the kit. More tools and features will be added in the future.