How to Transform XML with xsltproc (with examples)

The xsltproc command-line utility is an essential tool for transforming XML documents using XSLT (Extensible Stylesheet Language Transformations). XSLT is a language for transforming XML documents into other formats, typically HTML, XML, or plain text. The xsltproc utility, which is part of the libxslt library, provides an efficient way to apply these stylesheets and produce the desired output, benefiting those working in web development, data processing, and publishing contexts.

Use case 1: Transforming an XML file with a specific XSLT stylesheet

Code:

xsltproc --output path/to/output_file.html path/to/stylesheet_file.xslt path/to/file.xml

Motivation:

Imagine you are tasked with converting a dataset from an XML format into a more user-friendly HTML document that can be hosted on a website. You need to present this data to stakeholders who are more comfortable viewing it in a standard web browser rather than parsing through raw XML. By using the xsltproc utility, you can automate this transformation process, easily turning complex XML structures into readable HTML documents.

Explanation:

• xsltproc: This is the command that invokes the xsltproc utility, responsible for processing the XSLT transformation.
• --output path/to/output_file.html: This option specifies the output file where the transformed HTML content will be saved. You must provide the full path to the file, ensuring it is correctly specified to store your resulting document.
• path/to/stylesheet_file.xslt: This parameter indicates the XSLT stylesheet file path, a crucial element required by the xsltproc utility. The stylesheet contains rules that define how the XML data should be transformed.
• path/to/file.xml: This is the XML file that you want to transform. Providing the correct path ensures that xsltproc can access and read the input data for transformation.

Example Output:

Suppose the XML file contains a list of book details, including title, author, and publication date. After processing with the appropriate XSLT stylesheet, xsltproc outputs an HTML document that formats these details in a table, making it easier to view and share online.

Use case 2: Passing a value to a parameter in the stylesheet

Code:

xsltproc --output path/to/output_file.html --stringparam "name" "value" path/to/stylesheet_file.xslt path/to/xml_file.xml

Motivation:

In some scenarios, the transformation of XML data depends on dynamic parameters that can affect how content is presented. For instance, you might want to highlight a specific author’s works in a catalog extraction. You can achieve this by passing parameters directly into the stylesheet, enabling conditional logic based on variable values, increasing the utility and flexibility of XML transformations.

Explanation:

• xsltproc: Like in the previous example, this command calls the xsltproc utility to perform the XSLT transformation.
• --output path/to/output_file.html: This argument specifies the destination of the output file, ensuring the transformed content is stored in the correct location for later use.
• --stringparam "name" "value": This crucial feature shows the flexibility of xsltproc, allowing dynamic data to be fed into the stylesheet. "name" is the parameter’s name as defined in the XSLT file, and "value" is the actual data you want to pass. This can modify the behavior of the stylesheet, like filtering results or altering the visual presentation.
• path/to/stylesheet_file.xslt: The XSLT stylesheet path here is where the transformation logic is defined, utilizing any parameters provided during processing.
• path/to/xml_file.xml: Indicates the input XML file that serves as the main data source to be transformed utilizing the stylesheet and any parameters.

Example Output:

If the XML file contains movie information and the parameter is used to filter only Oscar-winning movies, the output HTML might present a list of titles and directors, selectively focusing on award-winning productions.

Conclusion:

The xsltproc command is an invaluable tool for anyone needing to transform XML data using XSLT. It provides sophistication in processing with fundamental use cases, such as transforming XML to different outputs and managing transformations with dynamic parameters. By using this tool, developers and data professionals can automate and streamline their data presentation workflows significantly.