The Mythical XML

The Mythical XML
Mr. Thomas Lee
Center for E-Commerce Infrastructure Development
(CECID), The University of Hong Kong

HK Computer Society XML Specialist Group
Speaker’s Session
26 August 2003, HK Polytechnic University

Agenda

XML Basis
Web Services
XML Development in HK
Demo

26 August 2003 HKCS XMLSG Speaker's Meeting - Mythical XML 2

True or False?

XML = Extensible Markup Language
XML is an extension of HTML
– XML is going to replace HTML for Web
browsing
Tags are not predefined in XML
– You must define your own tags
XML specifies data semantics

Background of XML
eXtensible Markup Language
XML 1.0 became a W3C Recommendation in
1998
F.O.X (Father of XML) - Jon Bosak
– a SUN architect, who led a group to create XML
Over 20 XML-related specs at W3C in 2003
Over 200 XML application standards for
different industries registered at XML.org
– Finance, healthcare, e-government, mathematic,
telecom…

What is XML?
A markup language for documents containing structured
information
– i.e. a data format for structurally delimiting text data with tags
For computer-to-computer communication
HTML XML
Encode content and Encode structure + content
presentation (no presentation)
Tags are already defined for Tags are to be defined by
rendering the content on different applications for
browsers (one application only) processing the content
Semantics has already been Semantics is not defined in
defined in HTML spec XML spec

XML is not going to replace HTML

Weather
Forecast
in
Browser


Weather Forecast
in HTML


Weather Forecast in XML
Start Tag
1. <?xml version="1.0"?>
2. <WeatherForecast> Element
3. <City name="Hong Kong">
4. <Weather date="2003-08-26">Light Rain</Weather>
5. <Weather date="2003-08-27">Showers</Weather>
6. </City>
7. <City name="Beijing">
Attribute
8. <Weather date="2003-08-26">Cloudy</Weather>
9. <Weather date="2003-08-27">Thunder Shower</Weather>
10. </City>
Data Value
11. </WeatherForecast>
End Tag

XML Document Structure
WeatherForecast

City: City:
name=“Hong Kong” name=“Beijing”

Weather: Weather: Weather: Weather:
date=“2003-08-26” date=“2003-08-27” date=“2003-08-26” date=“2003-08-27”

Light Rain Showers Cloudy Thunder Showers


XSLT
XML Stylesheet Language Transformation
A scripting language to transform a XML document
to different document forms
– another XML form, HTML, text, etc.
Can present XML data in different rendering
languages, e.g. HTML, WML
– separation of content and presentation
Can translate to a different XML form (conforming
to a different XML schema)
– interoperability between different applications, e.g.
vendor products


XSLT Example
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:template match="/">
<html>
<head>
<title>Weather Forecast</title>
</head>
<body>
<h1>Weather Forecast</h1>
<xsl:apply-templates/>
</body>
</html>
</xsl:template>

XSLT Example (2)
<xsl:template match="City">
<h2>
<xsl:apply-templates select="@name"/>
</h2>
<table border="1">
<tbody>
<tr>
<th>Date</th>
<th>Weather</th>
</tr>
<xsl:apply-templates/>
</tbody>
</table>
</xsl:template>

XSLT Example (3)
<xsl:template match="Weather">
<tr>
<td>
<xsl:apply-templates select="@date"/>
</td>
<td>
<xsl:apply-templates select="text()"/>
</td>
</tr>
</xsl:template>
</xsl:stylesheet>


Schema Language
A schema language is used to validate the XML data whether
it is in valid form for a specific application
– the tag set
– the structure in which the tags can be placed
– the format of the values marked-up by tags and attributes values
Data Type Definition (DTD) and W3C XML Schema
To define an XML application standard
– e.g. XBRL (XML Business Reporting Language)
Not sufficient define semantics
– semantics is defined in a supplementary vocabulary or
specification
Not designed to program application logic
– e.g. cannot convert temperature between degrees Celsius and
Fahrenheit

XML Schema Example
encoding="UTF-
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
xs:schema xmlns: xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="WeatherForecast">
xs:element name="WeatherForecast">
<xs:complexType>
xs: complexType>
<xs:sequence>
xs:sequence>
<xs:element name="City" minOccurs="0" maxOccurs="unbounded">
xs:element name="City" minOccurs="0 maxOccurs="unbounded">
<xs:complexType>
xs: complexType>
<xs:sequence>
xs:sequence>
<xs:element name="Weather" minOccurs="0" maxOccurs="unbounded">
xs:element name="Weather" minOccurs="0 maxOccurs="unbounded">
<xs:complexType>
xs: complexType>
<xs:simpleContent>
xs: simpleContent>
<xs:extension base="xs:string">
xs:extension base="xs:string">
<xs:attribute name="date" type="xs:date" use="required"/>
xs:attribute name="date" type="xs:date" use="required"/>
</xs:extension>
</xs:extension>
</xs:simpleContent>
</xs:simpleContent>
</xs:complexType>
</xs:complexType>
</xs:element>
</xs:element>
</xs:sequence>
</xs:sequence>
<xs:attribute name="name" type="xs:string" use="required"/>
xs:attribute name="name" type="xs:string" use="required"/>
</xs:complexType>
</xs:complexType>
</xs:element>
</xs:element>
</xs:sequence>
</xs:sequence>
</xs:complexType>
</xs:complexType>
</xs:element>
</xs:element>
</xs:schema>
</xs:schema>


True or False (Answers)

XML = Extensible Markup Language
XML is an extension of HTML
– XML is going to replace HTML for Web
browsing
Tags are not predefined in XML
– You must define your own tags
XML specifies data semantics

Weather Info Everywhere


How to Automatically Obtain
Weather Info from HKO?
Now:
– poll HKO web pages
– “try” to decode the text contained within
(based on the current web page layout)
– 300+ have registered web sites, mass media,
telecom operators using this method
– problem: a slight change to layout or data
format would cause problems to these users
Better solution:
– Use Web Services

What is Web Service?
Remote procedure call (distributed
computing) on the Internet using XML
Exposes functionality through a standard
protocol
Describes the interfaces in enough detail
to for building client applications to talk to
them
Registers the services so that potential
users can find them easily


SOAP
Simple Object Access Protocol
Uses XML to package input and output data on
making a remote procedure call (RPC) on the
Internet
Uses Internet protocols for data transport, e.g.
HTTP, SMTP
– Firewall friendly
Platform independent
– .Net and Java programs can talk with each other in SOAP
http://www.w3c.org

SOAP Request
POST /weatherwarning/services/WeatherWarning HTTP/1.0
Content-Type: text/xml; charset=utf-8
Accept: application/soap+xml, application/dime, multipart/related, text/*
User-Agent: Axis/1.1RC2
Host: 127.0.0.1
Cache-Control: no-cache
Pragma: no-cache
SOAPAction: ""
Content-Length: ###

<soapenv:Envelope
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<ns1:getWarning
soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:ns1="http://model.weatherwarning.webservice.hko.cecid.hku.hk"/>
<ns1:type>typhoon</ns1:type>
</ns1:getWarning>
</soapenv:Body>
</soapenv:Envelope>

SOAP Response
HTTP/1.1 200 OK
Content-Type: text/xml; charset=utf-8
Date: Tue, 26 Aug 2003 02:25:37 GMT
Server: Apache Coyote/1.0
Connection: close

<soapenv:Envelope
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<ns1:getWarningResponse
soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:ns1="http://model.weatherwarning.webservice.hko.cecid.hku.hk">
<return xsi:type="xsd:string">強烈季候風信號</return>
</ns1:getWarningResponse>
</soapenv:Body>
</soapenv:Envelope>


WSDL
Web Services Description Language
Specifies the data types and structures (in XML
Schema) of input and output data for a SOAP call
Specifies other transport parameters, e.g. protocol,
URL end-point, etc.
Tells the clients how to make a SOAP call to use a
specific Web Service
– similar to Interface definition language (IDL) for RPC
http://www.w3c.org


UDDI
Universal Description, Discovery and Integration
A registry to register, publish, find Web Services
– white pages, or basic identification: name, address, and
key points of contact
– yellow pages, or classification by a standard index of
business and industries
– green pages, or technical capabilities and services related
to the conduct of electronic business
Similar to a portal for system clients
http://www.uddi.org


ebXML

E-business XML
Co-developed by UN/CEFACT and OASIS
XML-based document exchange architecture to
perform Electronic Data Interchange (EDI) on the
Internet
Provides reliable and secure document exchange
on the Internet
Supports business process specification for
system execution
Widely adopted in Asia and Europe
– HK is an ebXML forerunner

eProcurement Case
MTRC purchases office supplies from Saggio on
SaggioDirect.com
Past: plentiful of delivery notes, invoices, monthly
statements were sent in paper and reconciled
manually
Present: XML documents are transferred on the
Internet using ebXML
– automatic reconciliation
– save costs and trees
– procurement data ready for analysis and planning


eProcurement with ebXML
Delivery goods Saggio Logistics

MTRC
Users
SaggioDirect System

Workstations

MTRC Intranet System Web
Internet Server

Intranet
Server
XML document

Hermes
Extract data XML document
from XML
Hermes document


eLogistics Case
Shipping companies electronically submit
dangerous goods manifests to Marine
Department using ebXML
Participating pilot shipping companies:
OOCL and APL
Pilot production in July 2003
Saved data reentry required by Web
Will cover other port formality documents, e.g. pre-
arrival notification, general declaration…
Issue: need to design XML Schemas for various
port formality documents


Dangerous Goods Declaration with ebXML
Shipping
Agents Paper submission
1

W
eb
su Marine
bm
2 iss Dept
io n
Internet

Hermes XML submission Hermes
MSH 3 ebXML Message Service MSH
26 August 2003 HKCS XMLSG Speaker's Meeting - Mythical XML
over HTTP on VPN 32

XML Schema Design and
Management Guide
For HKSARG to implement e-government joined-up services
– enhance data interoperability
Systematic modelling methodology for designing reusable
XML Schemas
– facilitates design of consistent, quality and reusable schemas
– consolidated international best practices, e.g. CCTS, UBL
Flexible management framework for standardizing Common
Schemas, e.g. HKID Number, Person Name, Postal Address
– minimizes repetitive data alignment efforts by standardizing
schemas for commonly used data elements
Under public consultation
– http://www.itsd.gov.hk/itsd/english/infra/eif.htm
Pilot project: HK Observatory plans to broadcast weather
information in XML through Web Services/HTTP

Weather Information in XML/WS


Digital Trade and
Transportation Network
A neutral, high-tech, and value-added e-logistics
platform
– facilitate information flow & service integration
– pearl River Delta (PRD), regionally & globally
– based on open-standards, e.g. XML / ebXML
– SME is an important focus
– releases 1 and 2 completed in 12-15 months
Return on investment
– estimated investment: HK$3B over 17 years
– estimated benefit: HK$11B over 17 years
http://www.logisticshk.gov.hk


Proposed DTTN Architecture


Open-Source Software
(OSS) Development
Conditions to advance global e-commerce development
– high interoperability and reliability, low cost
– therefore, open standards and open-source software
HK is the world champion in ebXML OSS
FreebXML.org to promote the development and adoption of
open-source technologies for e-commerce
– international collaboration: HKU (HK), Cyclone (US), ECOM
(Japan), Kasetart U. (Thailand), KIEC (Korea), SigmaLogica (US),
Sterling Commerce (US), Sun (US), Sybase (US)
Our vision: FreebXML – the “Linux” and “Apache” in the e-
commerce development


Global Penetration of
Made-in-HK OSS

Many serious users in Asia and Europe!

About CECID
Center For E-Commerce Infrastructure Development
Technology focus: XML and Web Services
HKU R&D Center (15+ full-time staff)
Primarily funded by Innovation and Technology Fund
– establishment of ebXML infrastructure in HK
– business process and information interoperability platform
To enhance HK’s competitiveness in e-commerce development
– technology creation and transfer for the community
– provision of R&D and training services to businesses and the
government (R&D outsourcing)
– participation of international standardization initiatives


Our R&D Strategy
R&D

R&D Pilot Production
Products Projects Deployments

HK Lead
Projects / SIs
End
International
Collaborations
Users

When Should I Use XML?

When you need a buzzword in your
resume :-)


Thank You
Q&A
Email: ytlee@cecid.hku.hk
URL: www.cecid.hku.hk

The Mythical XML

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