Extensible Stylesheet Language

Extensible Stylesheet Language Jussi Pohjolainen TAMK University of Applied Sciences

XSL

E xtensible S tylesheet L anguage (XSL)

family of transformation languages

To format and / or transform XML – documents

XSL Family consists of three languages

XSL Transformations (XSLT)

XSL Formatting Objects (XSL-FO)

XML Path Language (XPath)

All languages are W3C recommendations

Relationships with the Languages Extensible Stylesheet Language XSL Transformations XSL Formatting Objects XML Path Language uses

Languages

XSL Transformations (XSLT)

XML language for transforming XML documents

XSL Formatting Objects

XML language for specifying visual formatting

XML Path Language

A non-XML language used by XSLT, addressing the parts of an XML document . Also available for use in non-XSLT contexts

Main Idea of XSLT XSLT Processor The XSLT Processor can be client-side (browser) or server-side (php, java..)

Without XSLT - link

With XSLT - link Now the XML document is linked to an external xslt document Browser is used as an XSLT processor. (client-side)

XSLT

XSLT is an transformation language.

With XSLT you can make transformations:

XML -> XML in General:

XML -> XHTML

XML -> SVG

...

XML -> HTML

XML -> TEXT

With XSLT you can transform a XML document to other text format (can be any).

XSL-FO

XSL-FO is a W3C Specified XML language for defining visual presentation.

Unified presentation language

No semantic markup

Example of an XSL-FO Document

<?xml version="1.0"?>

<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">

<fo:layout-master-set>

<fo:simple-page-master master-name="only">

<fo:region-body/>

</fo:simple-page-master>

</fo:layout-master-set>

<fo:page-sequence master-reference="only">

<fo:flow flow-name="xsl-region-body">

<fo:block font-size="20pt" font-family="serif" line-height="30pt">

Jussi Pohjolainen

</fo:block>

<fo:block color="red" font-size="30pt" font-family="serif">

jussi.pohjolainen(at)tamk.fi

</fo:block>

</fo:flow>

</fo:page-sequence>

</fo:root>

Transforming XSL-FO - document

Once XSL-FO document is generated, it is passed to a FO processor.

FO Processor converts the document into something that is readible, printable or both.

Most common output is PDF, PS, RTF.

FO Processors?

XEP, XSLFormatter, XINC and FOP

Example: XSL-FO and Processor XS Processor The possible output formats depends of the features of the XS processor. For example, Apache FOP supports only PDF

Generating FO documents

XSL-FO Documents are not meant to be implemented by the programmer.

XSL-FO Documents are generated

Well Who / What generates XSL FO Documents?

It's result of an XSLT – transformation

Main Idea of XSLT: XML -> XHTML XSLT Processor The XSLT Processor can be client-side (browser) or server-side (php, java..)

Main Idea of XSLT: XML -> FO XSLT Processor Now the books.xml is transformed into XSL FO language...

Example: XSL-FO and Processor XS Processor And if you have an fo-document, you can transform it to pdf (for example)

XSL-FO Process in Whole XS Processor XSLT Processor

Example

Converting XML to PDF using PHP and Apache FOP

Apache FOP

http://xmlgraphics.apache.org/fop/

Must be installed in your server

It is NOT installed in TAMK Environment

XSL-FO Process in Whole FOP PHP

PHP Code

<?php

// load xslt-file

$xslDoc = new DOMDocument();

$xslDoc->load("books_to_fo.xslt");

// load source xml-file

$xmlDoc = new DOMDocument();

$xmlDoc->load("books.xml");

// Make transformation

$proc = new XSLTProcessor();

$proc->importStylesheet($xslDoc);

$booksFo = $proc->transformToXML($xmlDoc);

// Save the fo document to a file

file_put_contents("books.fo", $booksFo);

// Use fop to create the pdf

shell_exec("fop books.fo books.pdf");

?>

XSLT AND XPATH

Relationships with the Languages Extensible Stylesheet Language XSL Transformations XSL Formatting Objects XML Path Language uses

XPath

Before learning the basics of XSLT, let's look at XPath

XPath is a non-XML language that is used with XSLT.

XPath is used also in other languages, like XPointer

XPath is a language for selecting elements, or nodes, from an XML – document

Selecting Nodes?

<A>

<B>

<C></C>

</B>

</A>

/A/B/C

XPath

Selecting Nodes (W3schools) Expression Description nodename Selects all child nodes of the named node / Selects from the root node // Selects nodes in the document from the current node that match the selection no matter where they are . Selects the current node .. Selects the parent of the current node @ Selects attributes

Examples (W3schools) Expression Description /bookstore Selects the root element bookstore bookstore/book Selects all book elements that are children of bookstore //book Selects all book elements no matter where they are in the document bookstore//book Selects all book elements that are descendant of the bookstore element, no matter where they are under the bookstore element //@lang Selects all attributes that are named lang

More Examples

/bookstore/book[1]

/bookstore/book[last()]

/bookstore/book[last()-1]

/bookstore/book[position()<3]

//title[@lang]

//title[@lang='eng']

/bookstore/book[price>35.00]

/bookstore/book[price>35.00]/title

Example of an XSLT-transformation: XML-file

<?xml version="1.0" encoding="utf-8"?>

<?xml-stylesheet type="text/xsl" href="transform.xslt"?>

<book>

<title>Programming with Java</title>

</book>

Example of an XSLT-transformation: XSLT-file

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:output method=" text " indent="yes" encoding="utf-8"/>

<xsl:template match="/">

Title: <xsl:value-of select=" /book/title "/>

</xsl:template>

</xsl:stylesheet>

Result: Simple text – file..

Title: Programming with Java

Making the Transformation

Implement a xml-document

Implement a xslt-document

Link these two together

Output the result with some processor

Browser, XML-editor, PHP, Java..

XSLT-transformation with PHP 5

<?php

// Load the transformation file

$xslt = new domDocument();

$xslt->load("transformation.xslt");

// Load the source xml file

$myXML = new DomDocument();

$myXML->load("original.xml");

// Add the transformation file to XSLTProcessor

$proc = new XSLTProcessor();

$proc->importStylesheet($xslt);

// Transform the xml and output the result

print $proc->transformToXml($myXML);

?>

Examples of XSLT

<xsl:output method=" text " indent="yes" encoding="utf-8"/>

Title: <xsl:value-of select=" /book/title "/>

</xsl:template>

</xsl:stylesheet>

Examples of XSLT

<xsl:output method=" html " indent="yes" encoding="utf-8"/>

<html><head><title></title></head>

<body>

<h1>Title: <xsl:value-of select="/book/title"/></h1>

</body>

</html>

</xsl:template>

</xsl:stylesheet>

Result of Previous XSLT

<html><head><title></title></head>

<body>

<h1>Title: Programming with Java</h1>

</body>

</html>

Is this valid xhtml?

Better Version

<?xml version="1.0" encoding="iso-8859-1"?>

<xsl:output method="xml" indent="yes" encoding="utf-8"

doctype-system="http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"

doctype-public="-//W3C//DTD XHTML 1.0 Strict//EN" />

<html><head><title>Example</title></head>

<body>

<h1>Title: <xsl:value-of select="/book/title"/></h1>

</body>

</html>

</xsl:template>

</xsl:stylesheet>

<xsl:value-of select="XPath"/>

With <xsl:value-of> you can select an element from the source file

The value of the select attribute is XPath expression

<xsl:value-of select="books/book/name"/>

for-each

<body>

<xsl:for-each select="/books/book">

<p><xsl:value-of select="title"/></p>

</xsl:for-each>

</body>

</html>

</xsl:template>

</xsl:stylesheet>

Repeat for every book..

sort

<body>

<xsl:for-each select="/books/book">

<xsl:sort select="price" order="ascending"/>

<p><xsl:value-of select="title"/></p>

</xsl:for-each>

</body>

</html>

</xsl:template>

</xsl:stylesheet>

Repeat for every book.. ..and sort them by price

Why this doesn't work?

<body>

<img src=" <xsl:value-of select="books/book/url"/> " />

</body>

</html>

</xsl:template>

</xsl:stylesheet>

What's wrong with this line?

Using attribute

<body>

<img>

<xsl:attribute name="src">

<xsl:value-of select="books/book/url"/>

</xsl:attribute>

</img>

</body>

</html>

</xsl:template>

</xsl:stylesheet>

Extensible Stylesheet Language

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