XSLT

XSLT (Extensible Stylesheet Language Transformations) is a transformation language used to transform XML documents into other formats. XSLT operates on the XML document object model, meaning that it can transform any XML document regardless of how it was created. XSLT is a powerful tool in the world of web development, enabling developers to transform XML data into a wide variety of formats, including HTML, XHTML, and PDF.

Purpose

The purpose of XSLT is to transform XML data into other formats. This is achieved through the use of XSLT templates, which define how the data should be transformed. XSLT provides a way to convert the hierarchical structure of an XML document into a different output format, while maintaining the integrity of the data.

XSLT is used in a wide variety of applications, including web development, data integration, and document publishing. It is particularly useful in situations where data needs to be transformed into different formats. For example, XSLT can be used to transform an XML document into an HTML web page, or to transform a database query result into an XML document.

Usage

XSLT is typically used in conjunction with XML documents. The XML document serves as the input to the XSLT transformation, and the XSLT stylesheet provides the instructions for transforming the input into the desired output format. XSLT stylesheets can be written using any text editor, and they must conform to the XSLT specification.

XSLT is used in a variety of web development scenarios. For example, it can be used to transform XML data into HTML for display on a web page. XSLT can also be used to generate RSS feeds, or to transform data into other formats for use in web services.

XSLT is also used in data integration scenarios. For example, it can be used to transform data from one format to another, such as transforming a CSV file into an XML document. XSLT can also be used to transform data from one database system to another.

XSLT is also used in document publishing scenarios. For example, it can be used to transform an XML document into a PDF file for printing or distribution.

XSLT Templates

XSLT templates are the building blocks of an XSLT stylesheet. They define how the input XML document should be transformed into the desired output format. XSLT templates consist of two parts: a match pattern and a template body.

The match pattern specifies which nodes in the XML document the template should be applied to. For example, the match pattern “//book” would apply the template to all of the book elements in the XML document.

The template body specifies how the matched nodes should be transformed. This can include adding new elements, deleting elements, or modifying existing elements. The template body is written using XSLT elements and functions.

XSLT templates can also include other templates, allowing for complex transformations to be built up from smaller, reusable components. This is often used in situations where certain parts of the transformation are repeated throughout the stylesheet.

XSLT Elements

XSLT provides a rich set of elements for defining the transformation rules. These elements can be divided into three categories: control elements, output elements, and function elements.

Control elements are used to control the flow of the transformation. They include elements like “choose”, “if”, and “for-each”. These elements allow the transformation to make decisions based on the input data, or to loop over a set of nodes.

Output elements are used to generate the output format. They include elements like “text”, “element”, and “attribute”. These elements allow the transformation to generate new elements and attributes in the output document.

Function elements are used to perform calculations and other operations on the input data. They include elements like “sum”, “substring”, and “concat”. These elements allow the transformation to manipulate the data in various ways.

Example

Here is an example of a simple XSLT stylesheet that transforms an XML document into an HTML table:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="html"/>

  <xsl:template match="/">
    <html>
      <head>
        <title>Book List</title>
      </head>
      <body>
        <table>
          <tr>
            <th>Title</th>
            <th>Author</th>
            <th>Price</th>
          </tr>
          <xsl:for-each select="bookstore/book">
            <tr>
              <td><xsl:value-of select="title"/></td>
              <td><xsl:value-of select="author"/></td>
              <td><xsl:value-of select="price"/></td>
            </tr>
          </xsl:for-each>
        </table>
      </body>
    </html>
  </xsl:template>
</xsl:stylesheet>

This stylesheet takes an XML document containing a list of books, and transforms it into an HTML table. The “match” attribute of the “xsl:template” element specifies that this template should be applied to the root node of the XML document. The “for-each” element loops over each “book” element in the XML document, and generates a row in the HTML table for each book. The “value-of” element extracts the value of the “title”, “author”, and “price” elements from the XML document, and inserts them into the HTML table.