Static site generation: Ant task for previewing articles

First steps to creating a static site generator using Apache Ant. The build file has several stub Ant tasks, but the only one that works is the previewArticle task, which is also the default. This task prompts for an article ID (e.g. "000612"), then runs the XSLT to create an HTML preview of that article. To test, run ant -lib common/lib or ant -lib common/lib previewArticle from the repository main directory, and fill in an article identifier when prompted. An alternative is to set the article.id property when calling Ant, e.g. ant -lib common/lib -Darticle.id=000612. The HTML will be saved to dhq-journal/dhq-preview/ARTICLE-ID.html.

Changes:

Added the Saxon HE JAR (v11.5) to common/lib, as well as Saxon's dependencies and licenses
Added dhq-preview to the .gitignore file
Started a new XSLT common/xslt/generate_static_articles.xsl, which will use the DHQ table of contents to fill out the static site HTML with transformed articles
Small tweaks to head.xsl:
- Add a parameter $assets-path which points to the DHQ assets directory. This value is used for <link>s and <script>s within the HTML <head>
- Take the first //titleStmt/title to fill in the HTML <title>
Small tweaks to template_article.xsl:
- Commented out parameters $vol, $issue and $id, since they are already set (with default values) in the included XSLT dhq2html.xsl
- Added default value for parameter $fpath, which uses volume, issue, and ID values to figure out the article's filepath
- Use included parameter $vol_no_zeroes from dhq2html.xsl when checking to make sure an article is in the TOC

Possible issues:

~~The Ant task may not work on Windows machines due to the directory separator being a forward slash~~ Still needs testing on Windows machines. However, the build file now uses the file.separator property for OS-agnostic filepaths
The previewArticle task does not fail on transformation error, this may not be helpful in the long run

Thanks to @joelsjlee, we discovered that Saxon HE requires that the xmlresolver JAR be available in the Java environment, or the Ant transformation fails with an ambiguous

[xslt] Caught an error during transformation: java.lang.reflect.InvocationTargetException

While Ant provides two methods for setting the classpath for an <xslt> task, neither actually pulls in the xmlresolver JAR. Saxon's documentation says that these methods are "unreliable", stating "the safest approach is to ensure that the Jar files needed to run Saxon are present on the externally-specified classpath (the classpath at the point where Ant is invoked), rather than relying on the task-specific classpath." Getting access to the JAR therefore requires user intervention at a technical level, such as by placing the JAR in ~/.ant/lib.

This Ant build file is intended for use by people who may not have a lot of confidence with the command line or Java's complex needs, and so I added a check for the Java class org.xmlresolver.Resolver. If the class is available, transformation can occur. If not, the new checkXmlResolver task describes how to run Ant with the -lib option, e.g. ant -lib common/lib. (On Windows machines, the forward slash will display as a backward slash.)

Digital-Humanities-Quarterly / dhq-journal

Static site generation: Ant task for previewing articles #38