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Orion Ifland / 2008-11-04. Introduction to XSLT. Introduction to XSLT. Agenda 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
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Orion Ifland / 2008-11-04 Introduction to XSLT
Introduction to XSLT • Agenda 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?
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
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
XML Refresh/Terminology • XML Nodes • Processing instruction: <?pi ... ?> • Element: <element /> or <element></element> • Attribute: <element attribute="value" /> • Comment: <!-- comment --> • Entity: & • Text node (just plain text)
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
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
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 />
XML Namespaces • Example: XHTML • <html xmlns="http://www.w3.org/1999/xhtml"> • <head> • <title></title> • </head> • <body> • <p> </p> • </body> • </html>
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>
XPath: Addresses for XML XPath 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>
XPath: Addresses for XML XPath 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>
XPath: Addresses for XML XPath 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>
XPath: Addresses for XML XPath 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> Predicate
XPath: Addresses for XML XPath 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>
XPath: Addresses for XML XPath 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>
XPath: Addresses for XML XPath Node selectors /library/* /library/book[1]/text() /library/node()[1] . <library> <!-- comment --> <book>The Principles of Computer Hardware</book> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Node selectors /library/* /library/book[1]/text() /library/node()[1] . <library> <!-- comment --> <book>ThePrinciples of Computer Hardware</book> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Node selectors /library/* /library/book[1]/text() /library/node()[1] . <library> <!-- comment --> <book>The Principles of Computer Hardware</book> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Node selectors /library/* /library/book[1]/text() /library/node()[1] . <library> <!-- comment --> <book>The Principles of Computer Hardware</book> <book name="The Fourth Civilization" /> </library> Selects the "current" node
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Functions //book[last()] count(//book) name(/*) //book[contains(@name, "C++")] //book[not(contains(@name, "C++"))] <library> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Functions //book[last()] count(//book) name(/*) //book[contains(@name, "C++")] //book[not(contains(@name, "C++"))] Returns: 2 <library> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Functions //book[last()] count(//book) name(/*) //book[contains(@name, "C++")] //book[not(contains(@name, "C++"))] Returns: "library" <library> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Functions //book[last()] count(//book) name(/*) //book[contains(@name, "C++")] //book[not(contains(@name, "C++"))] <library> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath Functions //book[last()] count(//book) name(/*) //book[contains(@name, "C++")] //book[not(contains(@name, "C++"))] <library> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML Other Useful XPath Functions position() – 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"
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML XPath 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> <book name="C++ How to Program" /> <book name="The Fourth Civilization" /> </library>
XPath: Addresses for XML Namespaces xmlns: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>
Try it out Make an XML file Make an XSLT file Run the transform and view the transformed data XSLT Basics <xml /> input <xsl:… /> transform <xml /> (or text) output
Sample XML <person> <name first="Neil" last="Armstrong" /> <quote>...one giant leap for mankind.</quote> </person> Sample Output Neil 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> XSLT Basics
Sample XML <person> <name first="Neil" last="Armstrong" /> <quote>...one giant leap for mankind.</quote> </person> Sample Output Neil 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> XSLT Basics
Sample XML <person> <name first="Neil" last="Armstrong" /> <quote>...one giant leap for mankind.</quote> </person> Sample Output Neil 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> XSLT Basics
Sample XML <person> <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> XSLT Basics All well-formed
Sample XML <person> <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> XSLT Basics
Sample XML <person> <name first="Neil" last="Armstrong" /> <quote>...one giant leap for mankind. </quote> </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> XSLT Basics
Sample XML <person> <name first="Neil" last="Armstrong" /> <quote>...one giant leap for mankind. </quote> </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> XSLT Basics
Sample XML <person> <name first="Neil" last="Armstrong" /> <quote>...one giant leap for mankind. </quote> </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> XSLT Basics
Sample 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> Sample XSLT HTML <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:for-each select="*"> <h1> <xsl:value-of select="name(.)" /> </h1> </xsl:for-each> </body></html> </xsl:template> </xsl:stylesheet> XSLT Loops: for-each
Sample 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> Result HTML <html><head><title>Zoo</title></head><body> <h1> birds </h1> <h1> mammals </h1> </body></html> XSLT Loops: for-each
Sample 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> Sample XSLT HTML <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: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> </xsl:template> </xsl:stylesheet> XSLT Loops: for-each
Sample 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> 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> XSLT Loops: for-each
<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> </xsl:template> </xsl:stylesheet> XSLT Loops: apply-templates 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>