1 Introduction to XSLT Orion Ifland / 2008-11-04.

1

Introduction to XSLTOrion Ifland / 2008-11-04

2

Introduction to XSLTAgenda

The X* Ecosystem (XSL, XPath, XQuery...)

XML Refresh/Terminology

XPath: Addresses for XML documents

XSLT Basics: template and value-of

XSLT Loops: apply-templates and for-each

XSLT Decisions: if and choose

XSLT Variables: variable and param

XSLT Extras: sort, copy-of, document…

Why/When XSLT?

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The X* Ecosystem XSL(T): Extensible Stylesheet Language

(Transforms) Like a giant function with a domain of XML

and a range of XML, HTML and Text XSL-FO (Formatting Objects) is a related,

graphics/print-oriented language XPath: XML Path (addressing)

Like a filesystem path in an XML document Also like RegEx

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The X* Ecosystem XQuery / XPath 2.0 / XSLT 2.0

Kind of jumbled together XQuery looks more like a mix of XSLT, SQL,

and Javascript (including lots of XPath) XMLNS (XML Namespaces)

Like programming language namespaces, distinguishes between elements/attributes with the same name

Used by XSLT and many other XML dialects

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XML Refresh/Terminology XML Nodes

Processing instruction: <?pi ... ?> Element: <element /> or

<element></element> Attribute: <element attribute="value" /> Comment:  Entity: & Text node (just plain text)

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XML Refresh/Terminology XML Syntax Rules

Escape < > & (turn them into entities < > &)

Every document has exactly one root element

Attribute values are always quoted Elements are case-sensitive (and are typically

lowercase) You don't have to put an xml processing

instruction at the top of your document

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XML Namespaces Reason

Gives context to the meaning of elements Disambiguates between elements with the

same name Challenges

Easy to forget to specify namespaces Non-forgiving

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XML Namespaces Syntax

Default namespace, e.g. xmlns="http://www.w3.org/xhtml/1999"<html />

Prefixed namespace, e.g. xmlns:dc="http://purl.org/dc/elements/1.1/"<dc:title />

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XML Namespaces Example: XHTML

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<title></title>

</head>

<body>

<p> </p>

</body>

</html>

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XML Namespaces Example: XSLT

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

<xsl:template match="/*">

<html> … </html>

</xsl:template>

</xsl:stylesheet>

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XPath: Addresses for XMLXPath Expressions/library

/library/book

/library/book/@name

/library/book[@name="The Fourth Civilization"]

/library/book[1]

//book[2]

<library>

<book name="C++ How to Program" />

<book name="The Fourth Civilization" />

</library>

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/library/book

/library/book/@name


/library/book[1]

//book[2]

<library>



</library>

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/library/book

/library/book/@name


/library/book[1]

//book[2]

<library>



</library>

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/library/book

/library/book/@name


/library/book[1]

//book[2]

<library>



</library>Predicate

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/library/book

/library/book/@name


/library/book[1]

//book[2]

<library>



</library>

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/library/book

/library/book/@name


/library/book[1]

//book[2]

<library>



</library>

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XPath: Addresses for XMLXPath Node

selectors/library/*

/library/book[1]/text()

/library/node()[1]

.

<library>



<book>The Principles of Computer Hardware</book>


</library>

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selectors/library/*


/library/node()[1]

.

<library>





</library>

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selectors/library/*


/library/node()[1]

.

<library>





</library>

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selectors/library/*


/library/node()[1]

.

<library>





</library>

Selects the "current" node

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XPath: Addresses for XMLXPath Axes/library/child::book

(or /library/book for short)

/descendent-or-self::book(or //book for short)

//book[1]/parent::*(or //book[1]/.. for short)

//book[2]/preceding-sibling::book

//book[1]/attribute::name(or //book[1]/@name for short)

<library>



</library>

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<library>



</library>

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<library>



</library>

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<library>



</library>

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<library>



</library>

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XPath: Addresses for XMLXPath Functions//book[last()]

count(//book)

name(/*)

//book[contains(@name, "C++")]

//book[not(contains(@name, "C++"))]

<library>



</library>

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count(//book)

name(/*)



Returns: 2

<library>



</library>

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count(//book)

name(/*)



Returns: "library"

<library>



</library>

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count(//book)

name(/*)



<library>



</library>

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count(//book)

name(/*)



<library>



</library>

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XPath: Addresses for XMLOther Useful XPath Functionsposition() – provides the position in a list (nice for numbering a

sequence of nodes)

sum(xpath) – takes a sequence of nodes and adds up their numerical values – see also avg(), min(), max()

concat(string, string, …) – exactly what you think

string-length(string) – returns the number of characters

substring(string, start[, length]) – the first char is at 1

translate(source-string, find-string, replace-string) – looks for individual chars and replaces themExample: translate("ABCD", "BD", "bd") "AbCd"

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XPath: Addresses for XMLXPath Operators//book[last() or

contains(@name, "C++")]

//book[string-length(@name) > 5]

//book[1] | //book[2]

Other operators:

and, =, >, <=, >=, !=, +, -, *, div, mod

Don't forget to escape < >!

<library>



</library>

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//book[1] | //book[2]

Other operators:

and, =, >, <=, >=, !=, +, -, *, div, mod


<library>



</library>

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//book[1] | //book[2]

Other operators:

and, =, >, <=, >=, !=, +, -, *, div, mod


<library>



</library>

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//book[1] | //book[2]

Other operators:

and, =, >, <=, >=, !=, +, -, *, div, mod


<library>



</library>

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XPath: Addresses for XMLNamespacesxmlns:y="http://x"

/y:library

/y:library/y:book

/y:library/y:book/@name

Namespaces must be declared in the XSLT document – prefixes aren't "imported" from the source document

<x:library xmlns:x="http://x">

<x:book name="C++ How to Program" />

<x:book name="The Fourth Civilization" />

</x:library>

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XSLT Basics• Try it out

– Make an XML file– Make an XSLT file– Run the transform

and view the transformed data

<xml />input

<xsl:… />transform

<xml />(or text)output

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XSLT BasicsSample XML<person>

<name first="Neil" last="Armstrong" /><quote>...one giant leap for mankind.</quote>

</person>

Sample OutputNeil Armstrong said "...one

giant leap for mankind."

Sample XSLT<xsl:stylesheet version="1.0"

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"><xsl:output method="text" /><xsl:template match="/person">

<xsl:value-of select="concat(name/@first, ' ', name/@last)" />

said "<xsl:value-of select="quote"

/>"</xsl:template>

</xsl:stylesheet>

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</person>






said "<xsl:value-of select="quote"

/>"</xsl:template>

</xsl:stylesheet>

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</person>






said "<xsl:value-of

select="quote" />"</xsl:template>

</xsl:stylesheet>

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<name first="Neil" last="Armstrong" /><quote>...one giant leap for mankind. </quote>

</person>

Sample Output<html><head><title>Neil

Armstrong</title></head>

<body><blockquote>…one giant leap for mankind.</blockquote>

</body></html>

Sample XSLT HTML<xsl:stylesheet version="1.0" xmlns:xsl=

"http://www.w3.org/1999/XSL/Transform"><xsl:output method="html" /><xsl:template match="/person">

<html><head><title><xsl:value-of select="concat(

name/@first, ' ', name/@last)" />

</title></head><body><blockquote><xsl:value-of

select="quote" /></blockquote></body></html>

</xsl:template></xsl:stylesheet>

All well-formed

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</person>

Sample Output<html><head><title>Neil

Armstrong</title></head>

<body><blockquote>…one giant leap for mankind.</blockquote>

</body></html>


"http://www.w3.org/1999/XSL/Transform"><xsl:output method="html" /><xsl:template match="/person">

<html><head><title><xsl:value-of select="concat(

name/@first, ' ', name/@last)" />

</title></head><body><blockquote><xsl:value-of

select="quote" /> </blockquote>

</body></html></xsl:template>

</xsl:stylesheet>

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</person>

Sample Output<quote><speaker

firstname="Neil" lastname="Armstrong"/> <text>…one giant leap for mankind.</text>

</quote>

Sample XSLT XML<xsl:stylesheet version="1.0" xmlns:xsl=

"http://www.w3.org/1999/XSL/Transform"><xsl:output method="xml" /><xsl:template match="/person">

<quote><speaker firstname="{name/@first}" lastname="{name/@last}"/>

<text><xsl:value-of select="quote" /></text>

</quote></xsl:template>

</xsl:stylesheet>

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</person>



</quote>






</xsl:stylesheet>

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</person>



</quote>






</xsl:stylesheet>

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XSLT Loops: for-eachSample XML<zoo>

<birds><albatross pop="4" /><buzzard pop="2" /><chickadee

pop="12" /></birds><mammals>

<aardvark pop="5" /><bat pop="200" /><cheetah pop="2" />

</mammals></zoo>


"http://www.w3.org/1999/XSL/Transform"><xsl:output method="html" /><xsl:template match="/zoo">

<html><head><title>Zoo</title></head><body>

<xsl:for-each select="*"><h1>

<xsl:value-of select="name(.)" /></h1>

</xsl:for-each></body></html>


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</mammals></zoo>

Result HTML<html><head><title>Zoo</title>

</head><body><h1>

birds</h1><h1>

mammals</h1>

</body></html>

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</mammals></zoo>


"http://www.w3.org/1999/XSL/Transform"><xsl:output method="html" /><xsl:template match="/zoo">

<html><head><title>Zoo</title></head><body>

<xsl:for-each select="*"><h1><xsl:value-of select="name(.)" /></h1>

<ul><xsl:for-each select="*"><li><xsl:value-of select="name(.)" /> (<xsl:value-of select="@pop">)</li>

</xsl:for-each></ul></xsl:for-each></body></html>


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</mammals></zoo>

Result HTML<html><head><title>Zoo</title>

</head><body>

<h1>birds</h1>

<ul><li>albatross (4)</li>

…</ul>

<h1>mammals</h1>

<ul><li>aardvark (5)</li>…

</ul></body></html>

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XSLT Loops: apply-templates

<xsl:template match="birds | mammals"><h1><xsl:value-of

select="name(.)" /></h1><ul>

<xsl:for-each select="*"><li><xsl:value-of select="name(.)" /> (<xsl:value-of select="@pop"/>)</li>

</xsl:for-each></ul>


Sample XSLT <xsl:stylesheet version="1.0" xmlns:xsl=

"http://www.w3.org/1999/XSL/Transform"><xsl:output method="html" />

<xsl:template match="/zoo"><html><head><title>Zoo</title></head><body>

<xsl:apply-templates select="*" />

</body></html>

</xsl:template>

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XSLT Decisions: ifXML<zoo>




</mammals></zoo>

XSLT…<xsl:template match="birds | mammals">

<h1><xsl:value-of select="name(.)" /> </h1><p>We have more than 2...</p><xsl:if test="*[@pop > 2]">

<ul><xsl:for-each select="*[@pop > 2]">

<li><xsl:value-of select="name(.)" /></li>

</xsl:for-each></ul>

</xsl:if></xsl:template>…

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XSLT Decisions: ifSample XML<zoo>




</mammals></zoo>

Result HTML<html><head><title>Zoo</title></head><body>

<h1>birds</h1>

<p>We have more than 2...</p><ul><li>albatross</li><li>chickadee</li>

</ul>

<h1>mammals</h1>

<p>We have more than 2...</p><ul><li>aardvark</li><li>bat</li>

</ul></body></html>

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XSLT Decisions: chooseXML<zoo>




</mammals></zoo>

XSLT fragment<xsl:template match="birds | mammals">

<ul><xsl:for-each select="*"><li><xsl:value-of select="name(.)" />

(<xsl:choose><xsl:when test="@pop = 2">a couple</xsl:when>

<xsl:when test="@pop <= 5">a few</xsl:when>

<xsl:otherwise>many</xsl:otherwise></xsl:choose>)

</li></xsl:for-each></ul>

</xsl:template>

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XSLT Decisions: chooseSample XML<zoo>




</mammals></zoo>


<ul><li>albatross (a few)</li><li>buzzard (a couple)</li><li>chickadee (many)</li>

</ul><ul><li>aardvark (a few)</li><li>bat (many)</li><li>cheetah (a couple)</li>

</ul></body></html>

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XSLT Variables: variableXML<zoo>




</mammals></zoo>


<xsl:variable name="total-animals" select="sum(*/@pop)" />

<ul><xsl:for-each select="*"><li><xsl:value-of select="name(.)" />

(<xsl:value-of select="round(100 * @pop div $total-animals)"/>% of all <xsl:value-of select="name(..)"/>)


</xsl:template>

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XSLT Variables: variableSource XML<zoo>




</mammals></zoo>


<ul><li>albatross (22% of all birds)</li><li>buzzard (11% of all birds)</li><li>chickadee (67% of all birds)</li>

</ul><ul><li>aardvark (2% of all mammals)</li><li>bat (97% of all mammals)</li><li>cheetah (1% of all mammals)</li>

</ul></body></html>

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XSLT Variables: parameter

<xsl:template name="animal">

<xsl:param name="total" /><li>

<xsl:value-of select="name(.)" /> (<xsl:value-of select="round(100 * @pop div $total)"/>%)

</li></xsl:template>

XSLT fragments<xsl:template match="birds | mammals"><xsl:variable name="total-animals" select="sum(*/@pop)" />

<ul><xsl:for-each select="*"><xsl:call-template name="animal"><xsl:with-param name="total" value="$total-animals">

</xsl:call-template></xsl:for-each></ul>

</xsl:template>

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XSLT Variables: param <xsl:template name="animal">

<xsl:param name="total" /><li>

<xsl:value-of select="name(.)" /> (<xsl:value-of select="round(100 * @pop div $total)"/>%)

</li></xsl:template>

XSLT fragments<xsl:template match="birds | mammals"><xsl:variable name="total-animals" select="sum(*/@pop)" />

<ul><xsl:for-each select="*"><xsl:call-template name="animal"><xsl:with-param name="total" value="$total-animals">

</xsl:call-template></xsl:for-each></ul>

</xsl:template>

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XSLT Variables: paramXML<zoo>




</mammals></zoo>

XSLT fragment<xsl:param name="minimum-population" select="5" />

<xsl:template match="birds | mammals"><ul>

<xsl:for-each select="*[@pop >= $minimum-population]"><li><xsl:value-of select="name(.)" />

(<xsl:value-of select="@pop"/>)


</xsl:template>

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XSLT Variables: paramSource XML<zoo>




</mammals></zoo>


<ul><li>chickadee (12)</li>

</ul><ul><li>aardvark (5)</li><li>bat (200)</li>

</ul></body></html>

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XSLT Extras: sortXML<zoo>




</mammals></zoo>


<ul><xsl:for-each select="*">

<xsl:sort select="@pop" order="descending" data-type="number" />

<li><xsl:value-of select="name(.)" />(<xsl:value-of select="@pop"/>)


</xsl:template>

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XSLT Extras: sortSource XML<zoo>




</mammals></zoo>


<ul><li>chickadee (12)</li><li>albatross (4)</li><li>buzzard (2)</li>

</ul><ul><li>bat (200)</li><li>aardvark (5)</li><li>cheetah (2)</li>

</ul></body></html>

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XSLT Extras: copy-ofSource XML<person>


</person>

XML Output<quote><name first="Neil"

last="Armstrong"/> <text>…one giant leap for mankind.</text>

</quote>



<quote><xsl:copy-of select="name" />



</xsl:stylesheet>

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XSLT Extras: more elements xsl:text – writes literal text to the output

(useful for controlling whitespace or forcing exact, unescaped output)

xsl:processing-instruction – writes a PI like <?php… ?> or <?xml-stylesheet… ?> to the output

xsl:import and xsl:include – used to combine stylesheets (useful for XSLT libraries)

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XSLT Extras: more functions document(url) – opens an XML document

at the given location, returning its nodes as data that can be used by the templateExample: document('zoo.xml')/zoo//*[@pop = 2]

current() – similar to "." except that it always refers to the current node, even when used inside predicatesExample://*[@pop = current()/@pop]

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XSLT Extras: xml-stylesheetTo make an XML document show itself in a

transformed format, add this to the top:

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

This is particularly useful for XML like RSS

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Why/When XSLT? Web Standard

XSLT v 1.0 Recommended by W3C almost 10 years ago (it's stable and well understood)

Dozens of implementations and host languages (Java, .NET, PHP, C++…)

Wide tool support (Firefox, IE, Visual Studio, many text editors, full IDEs…)

No vendor lock-in

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Why/When XSLT? Very good at converting XML to XML,

XHTML/HTML, or plain text Makes it easy to keep things well-formed Uses XML syntax, so the only real new syntax

is XPath (which is also used elsewhere) XPath is far more compact than similar DOM

code in JS/Java/C#/etc. Can be interpreted (for quick development)

or compiled (for maximum performance)

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Introduction to XSLTQuestions, demos…

1 Introduction to XSLT Orion Ifland / 2008-11-04.

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Transcript of 1 Introduction to XSLT Orion Ifland / 2008-11-04.