XSL - Introduction and guided tour

Transcription

1 Concepts and Technologies of XML 6.1 XSL - Introduction and guided tour CT-XML 2014/2015 Warning! Authors " João Moura Pires (jmp@di.fct.unl.pt) " With contributions of Carlos Damásio (cd@di.fct.unl.pt) Joaquim Aparício Pedro Barahona (pb@di.fct.unl.pt)! These slides can be freely used for personal or academic matters without permission from the authors, as long as this author list is included.! The use of these slides for commercial matters is not allowed, unless authorized from the authors. 2

2 Summary! Introduction! XSL guided tour 3 XLST Introduction 6 - XLST

3 Introduction! The extensible Stylesheet Language (XSL) is an XML language which allows transformations on XML documents and their subsequent presentation.! It has significant contributes to the XML language objectives: " Separating data from presentation. " Facilitate data transfer between applications. " Unify data with documents. 5 Introduction Need for style sheets! The used tags in the XML document are not initially specified. They are user-defined.! Then, it is impossible to initially assume any meaning to the tags used in the documents. Namely, knowing which attributes or elements specify formatting information.! The XML document information might not be organised in the desired presentation format. 6 Introduction

4 Separating content and presentation! The content and style separation allows the use of the same content for production of various distinct document formats, either for human or machine consumption.! The presentation generation might be executed server or client side, depending of each side installed software. 7 Introduction XSL Recommendation! XSL (extensible Stylesheet Language) integrates a set of recommendations defined by the World Wide Web Consortium (W3C) with the objective of expanding Internet use.! The XSL proposal includes: " XPath (XML Path Language), a language to access parts of a XML document. " XSLT (XSL Transformations), a transformation language for XML documents. " XSL-FO (Formating objects), a vocabulary for formatting objects and respective properties. 8 Introduction

5 The Recommendations current state! Stable (recommendations): " XSLT 1.0 ( 1999/11/16) " XPath 1.0 ( 1999/11/16) " XSL 1.0 ( 2001/10/15)! Recent (recommendations) " XPath 2.0 ( in 23 January 2007) " XSLT 2.0 ( in 23 January 2007) " XQuery 1.0 and XPath 2.0 Data Model ( in 23 January 2007) 9 Introduction Other specifications dependences! XML 1.0 (Third Edition) ( XML Namespaces ( The XSLT 2.0 version support XML BASE ( xmlbase/) and XML SCHEMAS integration, allowing a big data type set. 10 Introduction

6 General XSLT characteristics! It uses XML to define its syntax.! There are no side effects: a variable after a value assignment cannot be reassigned again.! It is a declarative language: for each input pattern we define which output must be constructed.! It has an execution based on rule application (templates), whose order is irrelevant (or almost ). 11 Introduction Stylesheet processing! The XSLT language processes an XML document tree representation. That representation specification is found on the XPath language recommendation.! An XSLT processor generates an output representation which can be an XML, HTML, XSLT:FO or even a text document.! The XSLT processor applies a stylesheet to a document.! With the 2.0 version it is possible to generate more than one output document and it allows scripts inclusion than can contain definition of Java and JavaScript extension functions. 12 Introduction

7 Usual style sheet tasks! The reorganization of the input document in an appropriate output document: the information can be selected, grouped and reordered. Document part can also be removed, added or modified.! Element addition allows description of how the information is presented: page setup, information block definition (containers) and formatting attributes. 13 Introduction Generic processing diagram 14 Introduction

8 Some tools! XSLT processors " MSXML Parser Releases 3.0 SP1 (já incluído no IE6 e Windows XP) e MSXML 4.0 ( " XALAN ( " INFOTERIA ( " SAXON ( Editors " XML Spy ( " Oxygen ( " Formatting Objects Authoring Tool ( See more on: " DMOZ( XML/Style_Sheets/XSL/Implementations/) " XML Software ( 15 Introduction XLST XSL Guided Tour 6 - XLST

9 Generate HTML! Starting point: factura.xml <?xml version="1.0" encoding="utf-8"?> <store:invoice number="45" year="2001" xmlns:store=" Invoice text <client nipc=" "> Carlos Viegas Damásio <address xml:lang="pt"> <street>rua da Avenida Nº 4</street> Telheiras, Lumiar <postalcode number=" " place="lisboa"/>portugal</address> </client> <line number="1"> <product iva-tax="17">cd-rom</product> <quantity n="5"/> <price currency="euros"> 52</price> </line> <line number="2"> <chip:product iva-tax="17" xmlns:chip=" RAM 256Mb <chip:code>mem-ram-0x00123</chip:code> </chip:product> <quantity n="10"/> <price currency="escudos"> 97500</price> </line> </store:invoice> 17 XSLT guided tour! Arrival point: factura.html 18

10 Apply a stylesheet! The command line can be used or we can include in the input XML document a processing-instruction indicating the browser to apply the transformation: <?xml-stylesheet type="text/xsl" href="cabecalho.xsl"?>! This instruction should be placed immediately following the XML declaration <?xml version="1.0"?>! The instruction behavior is defined on XML StyleSheet recommendation 19 E01- Empty stylesheet effect! The empty stylesheet copies to the output all the text nodes existing in the input document, according to the corresponding document order. <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl=" </xsl:stylesheet> 20

11 E01- Empty stylesheet effect! The empty stylesheet copies to the output all the text nodes existing in the input document, according to the corresponding document order. <?xml version="1.0" encoding="utf-8"?> Carlos Viegas Damásio Rua da Avenida Nº 4 Telheiras, Lumiar Portugal CD-ROM 52 RAM 256MbMEM-RAM-0x E02- Invoice header <html xmlns:store=" <body> <p><b>factura Nº </b>45/2001 <p><b>cliente:</b> Carlos Viegas Damásio <p><b>morada:</b> Rua da Avenida Nº 4 Telheiras, Lumiar Portugal </body> </html> 22

12 E02- Invoice header <?xml version="1.0" encoding="iso "?> <xsl:stylesheet xmlns:xsl=" version="1.0" xmlns:store=" <?xml version="1.0" encoding="utf-8"?> <xsl:template match="/"> <store:invoice number="45" year="2001" <html> xmlns:store=" <body> <p><b>factura Nº </b> </store:invoice> <xsl:value-of /> <p><b>cliente:</b> <xsl:value-of select="//store:client/text()"/> <p><b>morada:</b> </body> </html> <xsl:value-of select="//store:address"/> </xsl:template> </xsl:stylesheet> 23 E02- Invoice header <?xml version="1.0" encoding="iso "?> <xsl:stylesheet xmlns:xsl=" version="1.0" xmlns:store=" <xsl:template match="/"> <html> <body> <p><b>factura Nº </b> <xsl:value-of /> <p><b>cliente:</b> <xsl:value-of select="//store:client/text()"/> <?xml version="1.0" encoding="utf-8"?> <p><b>morada:</b> <store:invoice number="45" year="2001" xmlns:store=" <xsl:value-of select="//store:address"/> <client nipc=" " Carlos Viegas Damásio </body> <address xml:lang="pt"> </html> <street>rua da Avenida Nº 4</street> </xsl:template> Telheiras, Lumiar </xsl:stylesheet> <postalcode number=" " place="lisboa"/>portugal</address> </client>.. </store:invoice> 24

13 E02- Invoice header <?xml version="1.0" encoding="iso "?> <xsl:stylesheet xmlns:xsl=" version="1.0" xmlns:store=" <xsl:template match="/"> <html> <?xml version="1.0" encoding="utf-8"?> <body> <store:invoice number="45" year="2001" xmlns:store=" <p><b>factura Nº <client </b> nipc=" " <xsl:value-of Carlos Viegas Damásio <address xml:lang="pt"> /> <street>rua da Avenida Nº 4</street> Telheiras, Lumiar <p><b>cliente:</b> <postalcode number=" " place="lisboa"/>portugal</address> <xsl:value-of select="//store:client/text()"/> </client>.. </store:invoice> <p><b>morada:</b> </body> </html> <xsl:value-of select="//store:address"/> </xsl:template> </xsl:stylesheet> 25 E02- Invoice header <?xml version="1.0" encoding="iso "?> <xsl:stylesheet xmlns:xsl=" version="1.0" xmlns:store=" <xsl:template match="/"> <html> <body> <p><b>factura Nº </b> <xsl:value-of /> <p><b>cliente:</b> <xsl:value-of select="//store:client/text()"/> <p><b>morada:</b> </body> </html> <xsl:value-of select="//store:address"/> </xsl:template> </xsl:stylesheet> 26

14 Default templates! For each XPath tree node type the XSL processor has pre-defined rules (templates).! Root and element template <!-- Root and element type nodes template --> <xsl:template match="* /"> <xsl:apply-templates/> <!-- Applies the templates to its children --> <!-- The children of an element don t include attribute or namespace type nodes --> </xsl:template> / elements PI comments element elements Text Comments 27 Default templates! Text and attribute type nodes template! Comment nodes template! Namespace nodes template " It s not possible to write this pre-defined template in XSL because there nothing like namespace() in XPath!! " The XSL processor include any necessary namespace declaration in the output <!-- Text and attribute type nodes template --> <xsl:template <!-- Writes the node textual value --> <xsl:value-of select="."/> </xsl:template> <!-- Processing instructions and comment nodes template --> <xsl:template match="processing-instruction() comment()"/> <!-- Doesn t do anything --> 28

15 E03 - Add lines to the invoice <html xmlns:loja=" <body> <table border="0" width="100%"> <tr bgcolor="#808080" bordercolor="#ffffff"> <td>qtd</td> <td>produto</td> <td>preço Unitário</td> <td>preço</td> <td>iva</td> <td>preço Final</td> </tr> <tr> <td>5</td> <td>cd-rom</td> <td> 52</td> <td>260</td> <td>44.2</td> <td>304.2</td> </tr> <tr> <td>10</td> <td>ram 256Mb </td> <td> 97500</td> <td>975000</td> <td>165750</td> <td> </td> </tr> </table> </body> </html> 29 E03 - Add lines to the invoice <?xml version="1.0" encoding="iso "?> <xsl:stylesheet xmlns:xsl=" version="1.0" xmlns:store=" <xsl:template match="/"> <html> <body> <p><b>factura Nº </b> <xsl:value-of select="concat(/store:invoice/@number,'/',/store:invoice/@year)" /> <p><b>cliente:</b> <xsl:value-of select="//store:client/text()"/> <p><b>morada:</b> </body> </html> <xsl:value-of select="//store:address"/> </xsl:template> </xsl:stylesheet> Processing the lines 30

16 E03 - Add lines to the invoice <table border="0" width="100%"> <tr bgcolor="#808080" bordercolor="#ffffff"> <td>qtd</td> <td>produto</td> <td>preço Unitário</td> <td>preço</td> <td>iva</td> <td>preço Final</td> </tr> <xsl:for-each select= store:invoice/line"> <tr> <!-- Processing each invoice line --> </tr> </xsl:for-each> </table> </body></html> 31 E03 - Add lines to the invoice <table border="0" width="100%"> <tr bgcolor="#808080" bordercolor="#ffffff">.. </tr> <xsl:for-each select= store:invoice/line"> <tr> <td><xsl:value-of select= quantity/@n"/></td> <td><xsl:value-of select="*[local-name()='product']/text()"/></td> <!-- unitary price --> <td><xsl:value-of select="price"/></td> <!-- Total price without tax = unitary price * quantity --> <td><xsl:value-of select="quantity/@n * price"/></td> <!-- IVA tax value = unitary price * quantity * IVA tax --> <td><xsl:value-of select="quantity/@n * price * (child::*/@iva-tax div 100)"/></td> <td><xsl:value-of select="quantity/@n * price * (1 + */@iva-tax div 100)"/></td> </tr> </xsl:for-each> </table> </body></html> <line number="2"> <chip:product iva-tax="17" xmlns:chip=" RAM 256Mb <chip:code>mem-ram-0x00123</chip:code> </chip:product> <quantity n="10"/> <price currency="escudos">97500</price> </line> 32

17 E03 - Put prices in Euros (1) Substitute <xsl:value-of select="price"/> By <xsl:if test="price/@currency='escudos'"> <xsl:value-of select="price div "/> </xsl:if> <xsl:if test="price/@currency='euros'"> <xsl:value-of select="price"/> </xsl:if> 33 E03 - Put prices in Euros (2) In alternative, for product price <xsl:value-of select="price"/> xsl:choose construction can be used <xsl:choose> <xsl:when test="price/@currency='escudos'"> <xsl:value-of select="quantity/@n * price div "/> </xsl:when> <xsl:otherwise> <xsl:value-of select="quantity/@n * price"/> </xsl:otherwise> </xsl:choose> 34

18 E03 - Put prices n Euros (3) Yet is simpler to define a varible <xsl:variable name="price"> <xsl:if test="price/@currency='escudos'"> <xsl:value-of select="price div "/> </xsl:if> <xsl:if test="price/@currency='euros'"> <xsl:value-of select="price"/> </xsl:if> </xsl:variable> <td><xsl:value-of select="quantity/@n * $price (child::*/@iva-tax div 100)"/> </td> <td> <xsl:value-of select="quantity/@n * $price * (1 + */@iva-tax div 100)"/> </td> 35 E03 - Number formatting! Your invoice presentation is already ok but The presented numbers have too many decimals.! We can defined various formats with " top element xsl:decimal-format " and then make use of the pre-defined function format-number. 36

19 E03 - Simplified code <xsl:variable name="unitary-price"> </xsl:variable> <td align="right"><xsl:value-of select="format-number($unitary-price,'#.00')"/></td> <xsl:variable name="preço" select="$unitary-price * quantity/@n"/> <td align="right"><xsl:value-of select="format-number($price,'#.00')"/></td> <xsl:variable name="iva" select="child::*/@iva-tax div 100"/> <td align="right"><xsl:value-of select="format-number($price * $iva,'#.00')"/></td> <td align="right"><xsl:value-of select="format-number($price * (1 + $iva),'#.00')"/></td> Thus we can obtain the intended result!! 37 Solution status! The produced code is not eye-pleasing. The invoice element processing is made in only one rule (template).! The result is confusing and not very modular.! We will describe how the invoice lines can be processed in parts 38

20 E04 - Additional rules creation! In first place, the code inside the xsl:for-each cycle is removed.! The code is then placed inside a template like this <xsl:template match="line"> </xsl:template>! The xsl:for-each element in the main template is replaced by <xsl:apply-templates select= store:invoice/line"/>! We get a new stylesheet producing the same output. 39 E04 - Additional rules creation <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet xmlns:xsl=" version="1.0" xmlns:store=" <xsl:template match="/"> <html> <body> <xsl:apply-templates select= store:invoice/line"/> </body> </html> </xsl:template> <xsl:template match="line"> <tr> </tr> </xsl:template> </xsl:stylesheet> 40

21 E05 - Calculation of totals! The XPath language has functions which allow summing and counting of node-sets.! To obtain the number of sold products we add the code: <HR/><p><b>Produtos Vendidos:</b> <xsl:value-of select="count(/store:invoice/line)"/>! The total quantity of sold products is obtained with: <p><b> Número de Artigos:</b> <xsl:value-of select="sum(//quantity/@n)"/>! Thus we can obtain the expected result. 41 And the invoice total???? 42

22 Data conversion! Our XML document was in an unfriendly format for invoice generation.! We will transform our XML document to another with a similar structure but with all the pretended information in the appropriate location.! The XSLT is very suited for this type of applications 43 XSL-T guided tour (data conversion) E06 - Invoice element conversion <xsl:template match= store:invoice"> <invoice number="{@number}" year="{@year}"> <xsl:apply-templates/> </invoice> </xsl:template> <store:invoice number="45 year="2001 xmlns:store=" </store:invoice> <invoice number="45 year="2001 > </invoice> 44 XSL-T guided tour (data conversion)

23 E06 - Client element conversion <xsl:template match="client"> <client NIF="{@nipc}"> <xsl:value-of select="text()"/> </client> <xsl:apply-templates select= address"/> </xsl:template> <store:invoice number="45" year="2001 xmlns:store=" <!-- CLIENT INFORMATION --> <client nipc=" "> Carlos Viegas Damásio <address xml:lang="pt"> <street>rua da Avenida Nº 4</street> Telheiras, Lumiar <postalcode number=" " place="lisboa"/> Portugal< /address> </client> <!-- INVOICE INFORMATION --> </store:invoice> <invoice number="45 year="2001 > <client NIF= > Carlos Viegas Damásio <cliente> </invoice> 45 XSL-T guided tour (data conversion) E06- Address element conversion <xsl:strip-space elements= address"/> <xsl:template match= address"> <address> <xsl:value-of select= street"/>, <xsl:value-of select="text()[1]"/>, <xsl:value-of select="concat(postalcode/@number,, cp/@place)"/>, <xsl:value-of select="text()[2]"/> </address> </xsl:template> <store:invoice number="45" year="2001 xmlns:store=" <!-- CLIENT INFORMATION --> <client nipc=" "> Carlos Viegas Damásio <address xml:lang="pt"> <street>rua da Avenida Nº 4</street> Telheiras, Lumiar <postalcode number=" " place="lisboa"/> Portugal< /address> </client> <!-- INVOICE INFORMATION --> </store:invoice> <invoice number="45 year="2001 > <client NIF= > Carlos Viegas Damásio <client> <address> Rua da Avenida Nº 4, Telheiras, Lumiar, Lisboa, Portugal </address> </invoice> 46 XSL-T guided tour (data conversion)

24 E06 - Address element conversion 47 XSL-T guided tour (data conversion) E06 - Line conversion (1) <xsl:template match="line"> <xsl:variable name= unitary-price"> <xsl:if test="price/@currecy='escudos'"> <xsl:value-of select="price div "/> </xsl:if> <xsl:if test="price/@currency='euros'"> <xsl:value-of select="price"/> </xsl:if> </xsl:variable> <xsl:variable name="price" select="$unitary-price * quantity/@n"/> <xsl:variable name="iva" select="child::*/@iva-tax div 100"/> <line number="2"> <chip:product iva-tax="17" xmlns:chip=" RAM 256Mb <chip:code>mem-ram-0x00123</chip:code> </chip:product> <quantity n="10"/> <price currency="escudos"> 97500</price> </line> 48 XSL-T guided tour (data conversion)

25 E06 - Line conversion (2) <line> <xsl:attribute name="qty"><xsl:value-of select="quantity/@n"/></xsl:attribute <xsl:attribute name="product"> <xsl:value-of select="*[local-name()='product']/text()"/> </xsl:attribute> <xsl:attribute name="unit"> <xsl:value-of select="$unitary-price"/> </xsl:attribute> <xsl:attribute name="price"><xsl:value-of select="$price"/></xsl:attribute> <xsl:attribute name="iva"><xsl:value-of select="$price * $iva"/></xsl:attribute> <xsl:attribute name="total"> <xsl:value-of select="$price * (1 + $iva)"/> </xsl:attribute> </line> <line number="2"> </xsl:template> <chip:product iva-tax="17" xmlns:chip=" <line qty="10 RAM 256Mb product="ram 256Mb <chip:code>mem-ram-0x00123</chip:code> unit=" </chip:product> <quantity n="10"/> price=" <price currency="escudos"> 97500</price> iva=" </line> total=" "/> 49 XSL-T guided tour (data conversion) E06 - Document conversion <?xml version="1.0" encoding="utf-8"?> <invoice number="45" year="2001" xmlns:store=" </invoice> <client NIF=" ">Carlos Viegas Damásio</cliente> <address>rua da Avenida Nº 4, Telheiras, Lumiar, Lisboa, Portugal</address> <line qty="5" product="cd-rom" unit="52" price="260" iva="44.2" total="304.2" /> <line qty="10" product="ram 256Mb" unit=" " price=" " iva=" " total=" " /> 50 XSL-T guided tour (data conversion)

26 E07 - Invoice formatting! The stylesheet is rebuild to accept documents in the previous format and to produce the desired result: <xsl:template match="line"> <tr> <td><xsl:value-of select="@qty"/></td> <td><xsl:value-of select="@product"/></td> <xsl:for-each select="@*[position()>2]"> <td align="right"> <xsl:value-of select="format-number(.,'#0.00')"/> </td> </xsl:for-each> </tr> </xsl:template> <line qty="5" product="cd-rom" unit="52" price="260" iva="44.2" total="304.2" /> <line qty="10" product="ram 256Mb" unit=" " price=" " iva=" " total=" " /> 51 XSL-T guided tour (HTML generation - 2) Header formatting! Very similar to the old stylesheet <xsl:template match="/"> <html> <body> <p><b>factura Nº </b> <xsl:value-of select="concat(invoice/@number,'/',invoice/@year)" /> <p><b>cliente:</b> <xsl:value-of select= invoice/client"/> <p><b>morada:</b> <xsl:value-of select= invoice/address"/> <?xml version="1.0" encoding="utf-8"?> <invoice number="45" year="2001" xmlns:store=" <client NIF=" ">Carlos Viegas Damásio</client> <address>rua da Avenida Nº 4, Telheiras, Lumiar, Lisboa, Portugal</address> <line qty="5" product="cd-rom" unit="52" price="260 iva="44.2" total="304.2" /> <line qty="10" product="ram 256Mb" unit=" price=" " iva=" " total=" " /> </invoice> 52 XSL-T guided tour (HTML generation - 2)

27 Table formatting <table border="0" width="100%"> <tr bgcolor="#808080" bordercolor="#ffffff"> <td>qtd</td> <td>produto</td> <td align="right">preço Unitário</td> <td align="right">preço</td> <td align="right">iva</td> <td align="right">preço Final</td> </tr> <xsl:apply-templates select= invoice/line"/> <tr> <td/><td/><td/><td/><td align="right"><b>total:</b></td> <td align="right"> <xsl:value-of </td> </tr> </table> 53 XSL-T guided tour (HTML generation - 2) Footer generation <HR/> <p><b>produtos Vendidos:</b> <xsl:value-of select="count(invoice/line)"/> <p><b>número de Artigos:</b> <xsl:value-of select="sum(invoice/line/@qty)"/> </body> </html> </xsl:template> 54 XSL-T guided tour (HTML generation - 2)

28 THE INVOICE! We can then combine the two processes to generation our HTML invoice: " First is generated the file with the convert document " The we apply the stylesheet to generate the invoice for browser reading. 55 XSL-T guided tour (HTML generation - 2) What have we seen from XSLT?! <xsl:template match= XPath"> </xsl:template> " Rule definition to apply to on the nodes which respect the pattern declared! <xsl:apply-templates select= XPath"/> " To apply the rules on the resulting nodes from the XPath query! <xsl:value-of select= XPath"/> " The textual value of the resulting nodes from the XPath query! <xsl:for-each select= XPath"> </xsl:for-each> " Interaction on the resulting node-set from the XPath query XSL-T guided tour 56

29 What have we seen from XSLT?! <xsl:choose> <xsl:when test= XPath"> </xsl:when> <xsl:otherwise> </xsl:otherwise> </xsl:choose>! <xsl:if test= XPath'"> </xsl:if> 57 XSL-T guided tour What have we seen from XSLT?! <xsl:variable name= name"> </xsl:variable>! <xsl:attribute name= unitary-price"> </xsl:attribute>! Direct output writing: " Elements (with or without attributes) " Text 58 XSL-T guided tour

30 Documents formatting! HTML document generation is not the most suited for quality document production to be used on various physical supports.! The XSL-FO vocabulary defines a set of objects, properties, traces, as well as a document formatting area model. The formatting objects tree has itself an XML representation.! A lot of objects and properties come from CSS2, assuring compatibly between both recommendations.! The CSS2 box model is a subset of the XSL-FO area model. 59 XSL guided tour (documents formatting) Output document generation! A stylesheet which manages an XML document is built in the XSL- FO vocabulary.! The stylesheet is applied to the initial XML document producing a XSL-FO document! An XSL-FO formatter is applied for the desired format.! In the future, there is hope the browsers will directly understand XSL-FO, unifying the output generation processes. 60 XSL guided tour (documents formatting)

31 E08 - A PDF invoice! The XHTML stylesheet is modified for the XSL-FO vocabulary ( facture.so.xsl)! First, the document layout is described.! Next, all the formatting objects are placed in the appropriate places, being themselves quite self-describing, and its completed with the information from the input document.! The XSL formatter which applies the XSLT processing is executed (the process might be separated): fop xsl factura.fo.xsl xml factura.xml factura.fo factura.pdf! The result is printed.! One can also present the document on the screen. 61 XSL guided tour (documents formatting) E08 - A PDF invoice 62 XSL guided tour (documents formatting)

32 Guided tour conclusion! The XSL language allow easy HTML generation.! The document format has impact the stylesheet programming.! It features a rule-application based processing mechanism.! It allows conversion of documents to different formats through specification of conversion rules.! The two previous processes can be combined 63 XSL guided tour