Simple Content Management System

Introduction Architecture Download Tutorial

Here at Explain we're very interested in XML pipelines. This is because they lie at the heart of content management systems that we create, like the Simple Content Management System (SCMS); a major component of the Packaged Press service. We started using the XML Pipeline Definition Language for specifying pipelines, but now we are building systems around XProc.

Introduction

Our first foray into the XProc world is the imaginatively named xproc application. This is an implementation of an XProc pipeline controller in XSLT. It comes in two flavours:

Command line: use the sh-libxml-fop.xsl XSL stylesheet to produce a Bourne shell script. Evaluating the shell script will build the products of the pipeline. This implementation uses libxslt's xsltproc and FOP.
GUI application: xproc.exe is an application for MS Windows (or the scms application on Mac OS X) that evaluates an XProc pipeline. It works by executing the XSL stylesheet tcl.xsl that produces a Tcl script, which is then evaluated to build the products of the pipeline.

The main difference between these implementations is that the shell script uses temporary files for the intermediate build products, whereas the Tcl/Tk application keeps the intermediate documents in memory (as DOM trees).

Architecture

The core stylesheet module is xsl/xproc.xsl. This module interprets a pipeline document and determines the products to build and their dependencies. The module makes calls to various named template to the real work, but within the module these are stubs.

A higher level stylesheet imports the core module and overrides the stubs to provide an implementation. Two examples are provided in the distribution: xsl/sh-libxml-fop.xsl and xsl/tcl.xsl. Both produce a text output; these are scripts which are evaluated to run the pipeline.

Download

SCMS is distributed as a zip file for MS Windows or as a disk image for Mac OS X. This contains the XSL stylesheets as well as the XProc MS Windows application or scms Mac OS X application. Download this file and unzip. Double-click xproc.exe (or scms) to run the program.

A sample pipeline and source documents is provided in the demo folder.

Tutorial

A tutorial on using the SCMS application.