Ten&Two XSLT Processor

The Ten&Two XSLT Processor plugin brings the power of PHP’s XSL extension to WordPress. Once enabled, the plugin creates three (3) shortcodes – [xslt_transform_xml/], [xslt_select_xml/], and [xslt_select_csv/] – which can be used separately or in tandem to enrich your site with content from XML and CSV sources. The plugin also enables two (2) custom post types – XSL Stylesheets and XML Documents – for managing and validating sources within WP Admin.

Detailed documentation and sample code can be found at https://plugins.tenandtwo.com/

Custom Post Types

The XSLT Processor plugin provides two (2) custom post types for managing sources within WordPress – XSL Stylesheets and XML Documents. Both types include basic syntax validation. XML Documents can be validated further using DTD, XSD, or RNG. Both types are enabled in Settings > XSLT Processor Settings > Activate Content Types.

Shortcode : [xslt_transform_xml/]

[xslt_transform_xml/] is the plugin's primary function.  This shortcode processes XML data using an XSL stylesheet, and then outputs the result as HTML, more XML, or as simple TEXT.

• [xslt_transform_xml xsl="{file|url|id|slug}" xml="{file|url|id|slug}" /]
• [xslt_transform_xml xsl="{file|url|id|slug}"]<DATA>...</DATA>[/xslt_transform_xml]

If either the xsl or xml parameter is left unspecified, defaults are used. The default XML value is <NODATA/>. The default XSL stylesheet prints all of the incoming data as HTML. If extra attributes are specified in the shortcode – eg, mykey="myval" – those keys/values are passed along as parameters to the stylesheet – <xsl:param name="mykey"/>.

Shortcode : [xslt_select_xml/]

[xslt_select_xml/] is a helper function.  It reads XML and returns a selection of the data, based on a supplied XPath expression.  There are two (2) options for specifying the XPath.  First, using the `select` attribute or, second, using the body of the shortcode.  Complex select statements with quotes, square brackets or other special syntax, should use the second pattern :

• [xslt_select_xml xml="{file|url|id|slug}" select="{XPath}" /]
• [xslt_select_xml xml="{file|url|id|slug}"]{XPath}[/xslt_select_xml]

If the XPath select parameter is left unspecified, the default / is used, which returns the entire document. The default output is format="xml". If format="json" is specified, the result is encoded as a JSON string.

Shortcode : [xslt_select_csv/]

[xslt_select_csv/] is a helper function for converting CSV file data to XML.  The result can be output directly as an HTML `<table>`, or the result can be passed to `[xslt_transform_xml/]` for further processing.

• [xslt_select_csv csv="{file|url}" /]
• [xslt_select_csv]{csv,data}[/xslt_select_csv]

Three (3) parameters – separator, enclosure, escape – control reading the input. See PHP’s fgetcsv() function for details.

• [xslt_select_csv separator="," enclosure="\"" escape="\\" /]

Two (2) parameters – key_row, col – control writing columns to the output. The key_row attribute is optional, but allows labels from that row to be used in col and key_col.

• [xslt_select_csv key_row="{num}" col="{num|letter|label}+" /]

Three (3) parameters – row, key_col, key – control writing rows to the output.

• [xslt_select_csv row="{num}+" /]
• [xslt_select_csv key_col="{num|letter|label}" key="{val}+" /]

Nested Shortcodes

Combine [xslt_transform_xml] with [xslt_select_xml] :

• [xslt_transform_xml][xslt_select_xml/][/xslt_transform_xml]

Combine [xslt_transform_xml] with [xslt_select_csv] :

• [xslt_transform_xml][xslt_select_csv/][/xslt_transform_xml]

Combine [xslt_transform_xml] with itself using [/xslt_transform_alias] (WP does not support nested shortcodes with identical names) :

• [xslt_transform_alias][xslt_transform_xml/][/xslt_transform_alias]

Combine multiple shortcodes/sources to create a single XML Document (see Custom Post Types above) :

• <DATA><PART1>[xslt_select_xml xml="f1.xml" /]</PART1><PART2>[xslt_select_xml xml="f2.xml" /]</PART2></DATA>

Cache Parameters

When a shortcode specifies a remote file – xml="{url}" or csv="{url}" – that source is cached locally using WP Transients. The default cache duration is set in the XSLT Processor Settings. To override the default, add cache="{minutes}" to the shortcode.

• [xslt_transform_xml xml="{url}" cache="{minutes}" /]
• [xslt_select_xml xml="{url}" cache="{minutes}" /]
• [xslt_select_csv csv="{url}" cache="{minutes}" /]

Namespace Parameters

Within [xslt_select_xml/] the plugin provides two (2) methods for handling XML containing namespaces. The first is to add strip-namespaces to the shortcode. The second method is to add the needed prefixes and namespace URIs using xslns.

• [xslt_select_xml xml="{file}" strip-namespaces="yes" select="//node" /]
• [xslt_select_xml xml="{file}" xmlns="ns1" ns1="{namespace-uri-1}" select="//ns1:node" /]
• [xslt_select_xml xml="{file}" xmlns="ns1 ns2" ns1="{namespace-uri-1}" ns2="{namespace-uri-2}" select="//ns1:node/ns2:node" /]

WP-CLI

All three (3) shortcodes have command-line equivalents. They can be used, for instance, to run quick tests. Or they can be used, by piping the outputs into files, to pre-generate results.

• wp xslt transform_xml
      --xsl='{file|url|id|slug}'
      --xml='{file|url|id|slug}'
      --cache='{minutes, if xsl|xml={url}}'
      --tidy='{yes|html}' or tidy or --tidy='xml'
      --{myparam}='{myvalue}'
      --outfile='{filepath}'
      --htmlentities or --htmlentities='yes'
  

• wp xslt select_xml
      --xml='{file|url|id|slug}'
      --cache='{minutes, if xml={url}}'
      --select='{xpath}'
      --root='{nodename|empty}'
      --tidy='{yes|html}' or tidy or --tidy='xml'
      --strip-namespaces='yes' or strip-namespaces
      --strip-declaration='no'
      --format='{xml|json}'
      --htmlentities or --htmlentities='yes'
  

• wp xslt select_csv
      --csv='{file|url}'
      --cache='{minutes, if csv={url}}'
      --separator=','
      --enclosure='\"'
      --escape='\\'
      --key_row='{row number for column labels}'
      --col='{return column number(s), letter(s), or label(s)}'
      --key_col='{col number, letter, or label for key matching}'
      --key='{value(s) for key_col matching}'
      --row='{return row number(s)}'
      --class='{css classname(s) for result table}'
      --htmlentities or --htmlentities='yes'
  

XSL Stylesheets

The XSLT Processor plugin includes a number of useful XSL templates that you can include and use in your own projects. They are grouped into five files.

• date.xsl : date-format, date-microtime
• file.xsl : file-exists-local, file-exists-remote
• string.xsl : string-replace, string-upper, string-lower, string-title-case, string-trim, string-rtrim, string-ltrim, string-maxlength, string-maxwords, string-add-slashes, string-urlencode, string-strip-tags, string-nl2br, string-entity-decode, string-to-nodeset
• util.xsl : util-bytsize, util-hash-data, util-print-nodes, util-print-node-names, util-super-global
• wp.xsl : wp-select-xml, wp-select-csv, wp-post-item, wp-post-meta, wp-sanitize-title, wp-size-format

Requirements

The Ten&Two XSLT Processor plugin relies upon PHP’s XSL extension. If the extension is installed, the XSLT Processor Settings screen will display a message similar to the first message below. If LIBXSLT_VERSION is undefined, all plugin options are disabled automatically and the second message is displayed.

• PHP's XSL extension is available : XSLT v1.1.32, EXSLT v1.1.32, LIBXML v2.9.4
• PHP's XSL extension is NOT available

The XSL extension’s requirements are detailed at php.net – https://www.php.net/manual/en/book.xsl.php

“This extension requires the libxml PHP extension. This means passing the –with-libxml,
or prior to PHP 7.4 the –enable-libxml, configuration flag, although this is implicitly
accomplished because libxml is enabled by default.

This extension uses libxslt which can be found at » http://xmlsoft.org/XSLT/. libxslt
version 1.1.0 or greater is required.”