Indenting XML Files using XSLT: A Step-by-Step Guide for R, Python, and PHP

Indenting XML Files using XSLT

To indent well-formed XML files, you can use an XSLT (Extensible Style-Sheet Language Transformations) stylesheet. Here is a generic XSLT that will apply to any valid XML document:

Generic XSLT

<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
   <xsl:output method="xml" indent="yes" encoding="utf-8" omit-xml-declaration="no"/>
   
   <xsl:strip-space elements="*"/>
   
   <xsl:template match="node()|@*">
      <xsl:copy>
         <xsl:apply-templates select="node()|@*"/>
      </xsl:copy>
   </xsl:template>
</xsl:stylesheet>

How to Use the XSLT

To apply this XSLT to an XML document, you’ll need a programming language that supports executing XSLTs. Here are examples for popular languages:

library(xml2)
xml <- read_xml("input.xml")
transformed_xml <- xml2::xslt_transform(xml, "generic_xslt.xsl")
write_xml(transformed_xml, "output.xml", format = c("format", "as_xml"))

Python (lxml)

import lxml.etree as ET

# Load the XML file and XSLT stylesheet
xml_file = ET.parse('input.xml')
xsl_stylesheet = ET.parse('generic_xslt.xsl')

# Apply the transformation
transformed_tree = xsl_stylesheet.apply(xml_file)

# Write the transformed result to a new file
ET.ElementTree(transformed_tree).write('output.xml', pretty_print=True)

PHP (XSLTProcessor)

$xml = simplexml_load_file('input.xml');
$xsl = simplexml_load_file('generic_xslt.xsl');

$processor = new XSLTProcessor();
$processor->importStylesheet($xsl);
$transformed_xml = $processor->transformToXml($xml);

file_put_contents('output.xml', $transformed_xml);

These examples demonstrate how to apply the generic XSLT to XML files in R, Python with lxml, and PHP. The process is straightforward: load the input XML file and the XSLT stylesheet, apply the transformation using the corresponding library’s functions, and write the transformed result to a new file.

Advice

Ensure that your input XML file is well-formed and valid according to the relevant XML standard.
Before applying any XSLTs to production code, test them thoroughly with sample inputs to ensure they produce the expected output.
Be mindful of performance considerations when using XSLTs for large-scale data transformations.

Last modified on 2023-05-09