University of Jyväskylä/AHo & VLy Experiences of Document Transformations with XSLT and DOM Anne Honkaranta, Virpi Lyytikäinen, Pasi Tiitinen, University

University of Jyväskylä/AHo & VLy

Experiences of Document Transformations with XSLT and DOMAnne Honkaranta, Virpi Lyytikäinen, Pasi

Tiitinen, University of Jyväskylä, Finland

inSGML project


Content

Poem Publishers, Inc. Poems Publishing environment

Transformations Tranformation techniques Transformations in server-client environment Tranformations in Poem Publishers, Inc

Challenges encountered Lessons learned


Poem Publishers, Inc. Fictional company Publishes Finnish poems on WWW Poems are authored in XML format

according to a DTD The company offers the poets an

authoring environment if so desired The poems can form collections


Poem.dtd


Publishing environment Microsoft IIS server v. 5.0 Jscript, VBScript ASP 3.0 DOM II Internet Explorer 5.5 or newer CSS Level 2 MSXML 3.0


Transformation Changing/converting document

format structure /information schema content organization filtering the content all the above

Conversion, filtering, and transformation are sometimes used as synonyms


Why you need transformations?

Authors need content-oriented DTD Different end-user devices When managing documents we

need to have them in an optimal format for processing

--> three-step publication process authoring -- processing -- output


Transformation techniques Event-based mapping technique

Tree-based mapping technique

Examples of languages

•SAX-Simple API for XML •Omnimark language/program

•DOM (document object model) — API•Balise language/program •XSLT language

Pros/cons.

•fast, uses computing resources efficiently•does not give very good control over schema (dtd, grammar) of an output document

•constructing a parse tree in memory takes resources •good control over schema of an output documen •best suited for complex (context) transformation)


Transformations in client-server environment (XSLT/DOM)

Alternatives: using PI in XML source document (c) (can be written to the source document on a

web server) DOM-interface and DOM objects for

loading the source XML and XSLT (c/s) using DOM-interface + scripting

language (Vbscript, Jscript) or Java


Transformation chain (an example)

OutputHTML/

XHTML docrenderedby CSS

Outputdoc. +link to

CSS

CSS doc.

SourceXMLdoc

XSLTdoc.

ClientServer/Client


Example:using PI in source XML<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href=”poem_html.xsl" ?><!DOCTYPE POEM SYSTEM "Poem1.dtd">...

<xsl:stylesheet.....<html><head><meta><LINK rel="stylesheet” type="text/css” href="runo_htm.css" ></LINK>


Example: using DOM-objects+XSLT

<HTML><BODY><HEAD></HEAD><SCRIPT LANGUAGE=VBSCRIPT>Dim objDocument, objXSL, strXML

Set objDoc = CreateObject("MSXML2.DOMDocument")Set objXSL = CreateObject ("MSXML2.DOMDocument")

objDoc.async=falseobjXSL.async=false

objDoc.Load "../Runot/Pinkku1.xml"objXSL.Load "runo1_htmlksi2.xsl"

strXML=objDoc.transformNode(objXSL)Document.Write strXML</SCRIPT></BODY></HTML>


Example: using Vbscript+DOM

<HTML><HEAD><TITLE>Inspect nodes of poem</TITLE></HEAD><BODY><SCRIPT LANGUAGE="VBSCRIPT" CODEPAGE="iso-8859-1" LCID="1033">Dim root, xmlDoc, child Set xmlDoc = CreateObject("Msxml2.DOMDocument")xmlDoc.async = FalsexmlDoc.load("Runot/Pinkku1.xml")

'Walk from the document to each of its child nodes:For Each child In xmlDoc.childNodes

document.write ”type of node:" & child.nodeType & " | " document.write ”name of node:" & child.nodeName & " | " document.write ”content of node:" & child.text & "<BR>"Next</SCRIPT></BODY></HTML>


Transformation ”types” tested in Poem Publishers, Inc. XML-to-XML XML-to-HTML XML-to-XHTML


Transformation needs tested in Poem Publishers, Inc. Tasks tested:

combining multiple source documents into output view (poem+header/footer, poem list, poem metadata)

combining multiple source documents into one file (making a poem collection)

combining XSLT transformation documents for transformation needs (poem+footer)


Example: combining XSLT-stylesheets

<?xml version=”1.0” encoding=”iso-8859-1”?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/1999/REC-html401">

<xsl:import href="header.xsl"/><xsl:output method="html" encoding="ISO-8859-1" />

<?xml version=”1.0” encoding=”iso-8859-1”?>!-- Filename: header.xsl --><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/1999/REC-html401"><xsl:output method="html" encoding="ISO-8859-1" /><xsl:template match="/" name="header">


Challenges Encountered Problems with

parsers and versions character encodings figures and links ”too many” tools, scripting

languages, and programs


Example: Character encodings and parser MSXML

INPUTDOC

MSXML3.0

OUTPUTDOC

-input doc encoding-maybe character entities-entities are changed to actual character reps.when transformed

-uses UTF-16-detects output encoding from PI when appropriate load/save methods used-otherwise outputs UTF-16

-has some encoding-has an encoding declaration-problem:either of them is ”wrong”


Possibilities you can use XSLT-stylesheets as

components and combine them a stylesheet can be seen as a re-usable

component on the server you can also chain transformations you can keep your data in content-

oriented form and provide multiple output versions by using transformations

problem: management of DTD’s, transformation components and versions


Lessons learned

Use same character encodings in source documents and transformation scripts

Offer a content oriented DTD for your authors; there is propably need for transformations anyway

Support level of CSS, XSLT and XML varies in browsers

Tools are available for building XML publishing environments: allow extra time for dealing with possible problems

Multiple skills and tools needed in publishing environment, XML is not enough!


More information: inSGML project http://haades.it.jyu.fi/inSGML/

Documents

University of Jyväskylä/AHo & VLy Experiences of Document Transformations with XSLT and DOM Anne Honkaranta, Virpi Lyytikäinen, Pasi Tiitinen, University