CERN European Organization for Nuclear Research IT Department

CERN – European Organization for Nuclear Research IT Department – e Business Section – Practical Use of XML Rostislav Titov IT-AIS-EB (e-Business) Section CERN – Geneva, Switzerland

XML e. Xtensible Markup Language l SGML (ISO standard, 1986) Mainly for technical documentation l XML (W 3 C recommendation, 1998) Simplification and enhancement of SGML, wide area of use CERN e Business –

Why Markup? <book lang=“Hungarian”> <chapter> Introduction Введение Текст </section> <section> Text Разметка <section> Markup </section> </chapter> <chapter> More document markup Дополнительные данные о разметке Reserved attributes </section> атрибуты <section> Зарезервированные Инструкцииinstructions по обработке <section> Processing </section> </chapter> </book> CERN e Business – Markup allows to add information about data structure

XML: Rules Header l One root element l Tag hierarchy l Attributes l Text elements l Empty elements l <? xml version="1. 0" encoding="UTF-8"? > <presentation> <author> <firstname>Rostislav</firstname> <lastname>Titov</lastname> </author> <chapter number="1" title="What is XML"> XML (Extensible Markup Language) is … </chapter> <conclusion/> </presentation> Some rules l Element names are case-sensitive l Every opening tag should have a closing tag l Tags cannot intersect (<a><b></a></b>) l Attributes values – in quotes or apostrophes CERN e Business –

XML: Data Transfer l Platform and language independent l Easy to write, easy to process l Understandable for humans and computers l Open standard – Many libraries exist – Lots of literature available – Specialized XML-editors l Possibility to check the document structure CERN e Business –

XML: Data Transfer (2) Example: EDH Transport Request XML External Program EDH l Automatic form generation from external programs l XML as data transfer format l Schema checkup as a warranty of data consistency CERN e Business –

Web Services Data transfer between programs on Internet l Open Standard l Platform and language independent (Java, . Net, …) l Web service XML SOAP XML WSDL – Web Service Definition Language SOAP – Simple Object Access Protocol CERN e Business –

XML: Data Storage l Data structure is kept together with the data l Object “addendum” to relational RDBMS l Structure checkup l Supported by many modern RDBMS – Microsoft SQL Server 2005, Oracle 9 i +, – XML Data Type – XML indexes – XML Queries (XQuery etc. ) – Data output in XML format CERN e Business –

XML: Data Storage (2) Example: EDH Search System Problem: Effective search using arbitrary number of criteria is problematic Our solution: l All documents are stored in XML l Context-specific XML search (Oracle Inter. Media) Example: «Find documents created by Slava» : Select DOC_ID from DOC_XML where Contains(XML, “Slava within creator”) > 0; CERN e Business –

XML: Data Transformations l XML can be transformed into HTML, text, PDF, . . . – No need for special program solutions – Commercial visual editors exist – Platform independent CERN e Business –

XML-based Standards l Possibility to formally define the structure l Platform and language independent l Understandable for humans and computers l Possibility to use XML technologies (XSLT transformations, XQuery queries)… – WSDL (Web Services Definition Language) – SOAP (Simple Object Access Protocol) – XHTML (HTML that complies to XML rules) – SVG (Scalable Vector Graphics) – eb. XML (XML for e-Business) – … CERN e Business –

Formal Structure Definition l There are ways to define XML structure formally Obsolete! Not for new development • DTD (Document Type Definition) • XML Schema CERN e Business –

XML Schema: Possibilities l Check element presence and their order l Sequences and choices l Number of repetitions for elements and groups l Attributes and their presence l Type of elements and attributes l Restrictions for elements and attributes l Default values l Unique constraints l . . . CERN e Business –

XML-schema: when it is needed? l Formal structure definition for future reference l Programmers may rely on data consistence l Authors advance CERN e Business – may check XML validness in

XML-schema: when NOT needed? l When we know in advance that XML is valid l When we do not care about document validness l When maximum processing speed is required l Small CERN e Business – “throw away” projects

XPath: XML Navigation l Access to XML elements l Result of an XPATH-expression can be: XML Node l Node Set l Boolean l C: presentationauthorfirstname CERN e Business – String l Number l Empty Set l /presentation/author/firstname

XPath: Examples l Find the DG’s name /cern/dg/person/text() l Find all departments /cern/department/@name l Find all people //person l Find the name of DH of IT <cern> <dg><person>R. Aymar</person></dg> <department name=“PH”> <dh><person>W-D. Schlatter</person></dh> </department> <department name=“IT”> <dh><person>W. von Rueden</person></dh> <group name=“IT-AIS”> <gl><person>R. Martens</person></gl> </group> <group name=“IT-CO”> <gl><person>D. Myers</person></gl> </group> <group name=“IT-IS”> <gl><person>A. Pace</person></gl> </group> </department> </cern> /cern/department[@name=“IT”]/dh/person/text() l Find how many groups has a department where R. Martens works count(//gl/person[starts-with(. , 'R. Martens')]/. . /group) CERN e Business –

XPath: Examples (8) Example: Event Handling System Events XML Subscriptions XPath Check events against XPath XML Notifications «I want to see all documents for more than 600 CHF» / document [amount > 600] CERN e Business – XPath

XPath: Program Use XPath System. out. println(((XMLDocument)xml). select. Single. Node( "/config/report[@name='Slava']/title/text()"). get. Node. Value()); DOM Model Element root = xml. get. Document. Element(); Node child; for (child = root. get. First. Child(); child != null; child = child. get. Next. Sibling()) if (child. get. Node. Name(). equals("report") && ( (Element)child ). get. Attribute("name"). equals("Slava")) break; for (child = ((Element)child). get. First. Child(); child != null; child = child. get. Next. Sibling()) { if (child. get. Node. Name(). equals("title") ) { for (Node child 2 = child. get. First. Child(); child 2 != null; child 2 = child 2. get. Next. Sibling()) if ( child 2 instanceof Text ) System. out. println(( (Text)child 2 ). get. Data(). trim()); CERN e Business – } }

XQuery –XML Query Language l XQuery is SQL for XML – Database independent – Easy to use l Supported by popular RDBMS (Microsoft SQL Server 2005, Oracle 9 i and 10 g) l Based on XPath, supports document sets CERN e Business –

XSLT: XML Transformations Transforms XML to HTML, text or other XML l XSLT 1. 0 (Current), XSLT 2. 0 (Draft) l XSLT is a “Human Interface” to XML l Supported by Web Browsers l XSLT CERN e Business –

XSLT: Simplified Structure XSLT is an XML file l Active usage of XPath expressions l xsl: stylesheet <html> <body> Evaluate XPath and print value xsl: value-of … xsl: template … xsl: value-of … xsl: apply-templates xsl: template Apply a template to the given element CERN e Business – … </body> <html> Apply templates to other elements

XSLT: Possibilities l l l l Conditions (<xsl: if>) Loops (<xsl: for-each>) Variables (<xsl: variable>) Sorting (<xsl: sort>) Numbering [1. , 1. 1. а, 2. , ] (<xsl: number>) Number formatting (format-number()) Multiple step processing (mode) String manipulations (via XPath) XSLT 2. 0 (Draft) l l l XPath 2. 0 Custom functions Regular expressions Date and time formatting Groupings CERN e Business –

XSLT: Example <xsl: stylesheet version="1. 0" xmlns: xsl="http: //www. w 3. org/1999/XSL/Transform"> <xsl: output method="html" version="1. 0" encoding="UTF-8" indent="yes"/> <xsl: template match="presentation"> <html> <body bgcolor="#FFCCFF"> <h 1><font color="darkblue"><xsl: value-of select="title"/></font></h 1> <h 4><font color="green"><i>Author: <xsl: value-of select="author"/></i></font></h 4> <b>Table of Contents</b><br/> <xsl: apply-templates select="chapter" mode="contents"/> <br/> <xsl: apply-templates select="chapter" mode="normal"/> </body> </html> </xsl: template> <xsl: template match="chapter" mode="normal"> <b>Chapter <xsl: value-of select="@number"/>. <xsl: value-of select="@title"/></b><br/> <i><xsl: value-of select="text()"/></i><br/> </xsl: template> <xsl: template match="chapter" mode="contents"> <xsl: value-of select="@number"/>. <xsl: value-of select="@title"/><br/> </xsl: template> </xsl: stylesheet> CERN e Business –

XSLT: Web “Skins” <aissearchscreen> <head><title>Person Search</title></head> <body> <input type="hidden" name="is. Advanced" value="false"/> <input show="always" type="text" label="Keyword" value="titov"/> <input type="checkbox" label="Fuzzy search" value="No"/> <result> <header> <tablecell>Full Name</tablecell> … </header> <row> <tablecell>Maksym TITOV</tablecell> <tablecell>71169</tablecell> <tablecell>40 -3 -C 08</tablecell> … </row> <tablecell>Oleg TITOV</tablecell> <tablecell>EXT</tablecell> … </row> … <rowcount>4</rowcount> </result> </body> </aissearchscreen> CERN e Business –

XSLT: Web “Skins” - 2 XSLT CERN e Business –

XSLT: User Interfaces CERN Stores Catalog l Data loaded through XML l Data stored in XML l XSLT for data output l 150000 items l +10000 users l ~15 -20 K XML for each page l Custom formatting (through XSLT redefinition) CERN e Business –

XSLT: XML to Text Example: l Automatic code generation XML-description <document> <input type=“person” name=“A”/> <input type=“number” name=“B”/> … </document> Did you know… that 1 EDH document is: l At least 20 source files (code, HTML templates, resources, SQL, …) l About 250 K of source code CERN e Business – Program Interface Business Logic. . . SQL

XSLT: XML to XML l Generate XML from another XML source l “Configuration files update” l XSL: FO CERN e Business –

XSL-FO: Formatting Objects l FO: XML-description of document layout l XSL-FO: XSLT transformation of XML document to FO document l FO Processor: program that converts the FO definition into a printable format (PDF, PS, . . . ) XML Document <? xml version="1. 0"? > <presentation> <title> XXX </title> </presentation> CERN e Business – FO Document XSL: FO Transformation <fo: root> <fo: page-sequence> <fo: flow>. . . </fo: flow> </fo: page-sequence> </fo: root> PDF Document FO Processor

XSL-FO: Formatting Objects FO has all capabilities of modern text editors: l l l Fonts Pagination Headers and footers Page numbering Odd/even page distinction Margins and intervals Keep paragraphs together Hangout lines Tables Graphics … CERN e Business – FO Processor: Apache FOP

XSL-FO: Example Web Interface e-MAPS XSLT XML XSL: FO Printable Version FOP Processor No extra code required l RTF to XSL: FO converters are good l Can be written by a student l Output format independent l CERN e Business –

XML Editors l Specially designed for XML editing l XML well-formedness and validity check l DTD and Schema visual editing l XML generation accordingly to DTD/Schema l Creation and debugging of XSLT and XSL: FO l Visual XSLT editing Example: Altova XML Spy (www. xmlspy. com) - Available from NICE - License can be obtained from the SDT service CERN e Business – XMLSpy 2005

XML: Program Handling l DOM (Document Object Model) – Tree building l SAX - much faster, DOM – more versatile SAX – Event handling – start. Element() – end. Element() Java, C++: – Apache Xalan – Oracle XML Parser CERN e Business – . . . PERL, . Net: – Built-in support

New Technologies Info. Path 2003 – Corporate system for electronic form handling – XML-based – Business rules defined by XML schema – Data validation using XML schemas l Adobe Intellegent Document Platform – Similar ideas l CERN e Business –

Conclusion «XML is one of the biggest inventions in IT area in the last few years. There is a lot of XML applications around the world today, and this amount will grow every year» W 3 C Consortium Web Site: http: //www. w 3 c. org Questions: Rostislav. Titov@cern. ch CERN e Business –