introduction to web services - coekrunapon/courses/178375/slides/intro2ws.pdf · introduction to...

Introduction to Web Services

Dr. Kanda Runapongsa, Dept. of Computer Engineering, KKU 1

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Dr. Kanda Runapongsa

([email protected])

Dept. of Computer Engineering

Khon Kaen University

2

Agenda

�Web Technologies

�What is a Web Service?

�Why Web Services?

�Where are Web Services?

�Web Services Architecture and Standards

�Web Services Development



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Web Applications (1/2)

�Application delivered to users from a web

server over a network such as the World

Wide Web or an intranet

�Users usually access Web application via

the Web browser

�Human interaction with programs

�HTML forms

�Web programming

4

Web Applications (2/2)

HTMLHTMLHTMLHTML

Client Side

• JavaScript• VBScript

Server SideServer SideServer SideServer Side

•ASP•PHP•JSP

Static Web

Dynamic Web



5

Traditional Web Interaction

HTMLHTMLHTMLHTMLWebWebWebWeb

ApplicationApplicationApplicationApplication

WebWebWebWeb

UserUserUserUser

6

Web Services Interaction

ApplicationApplicationApplicationApplication

Web ServiceWeb ServiceWeb ServiceWeb Service

XMLXMLXMLXML

WebWebWebWeb



7

Web Application vs. Web Services

�Web Application

� HTML

� User-to-program interaction

� Static integration of components

�Monolithic service

�Web Services

� XML

� Program-to-program interaction

� Dynamic integration of components

� Service aggregation

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Distributed Computing Technologies



9

Waves of Innovation

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Internet Evolution

Browse the Web

Programthe Internet

Technology

Standard

Web services

XML

Programmability

HTML

Web pages

PresentationFTP, e-mail, Gopher

TCP/IP

Connectivity

Innovation



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Agenda

�Web Technologies

�What is a Web Service?What is a Web Service?What is a Web Service?What is a Web Service?





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What is a Web Service?

�A Web service is a software systemsoftware systemsoftware systemsoftware system identified

by a URI,

�Whose public interfaces and binds are

defined and described using XMLdefined and described using XMLdefined and described using XMLdefined and described using XML

� Its definition can be discovered by other

software systems

�These systems may then interact with the

Web service in a manner prescribed by its

definition, using XML based messagesXML based messagesXML based messagesXML based messages

conveyed by Internet protocolsInternet protocolsInternet protocolsInternet protocols



13

Where do Web Services Come From?

�Two words: Web services

WWW SOA

Web servicesarchitecture

SOA =Service-orientedArchitecture

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Service-Oriented Architecture

Service BrokerService BrokerService BrokerService Broker

Service ConsumerService ConsumerService ConsumerService Consumer Service ProviderService ProviderService ProviderService Provider

ClientClientClientClient ServiceServiceServiceService

Service broker is Service broker is Service broker is Service broker is

OptionalOptionalOptionalOptional

interact

ServiceServiceServiceService

ContractContractContractContract

…………



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Characteristics of Web Services�XML based everywhere

�Message-based

�Programming language independent

�Could be dynamically located

�Could be dynamically assembled or aggregated

�Accessed over the internet

� Loosely coupled

�Based on industry standards

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Sample Web Service

User

Stock Quote Web ServiceInput: Symbol

Output: Price, News, Trade

SetTradeInput: SymbolOutput: Price

News feed 1Input: Symbol

Output: News links

…

News feed nInput: Symbol

Output: News links

Brokerage 1Input: Symbol, Price, Qty

Output: Analysis

Brokerage nInput: Symbol, Price, Qty

Output: Analysis

..



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Sample Web Services Usage Scenario

�E-commerce: order books, office supplies,

other products

�Track packages: UPS, FedEx

�Weather forecast

�Search location on Maps

�Telephone redirection, customizable rules

and messages

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Agenda

�Web Technologies


�Why Web Services?Why Web Services?Why Web Services?Why Web Services?


�Web Service Architecture and Standards

�Web Service Development



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� New user experience� Software for smart device� Connected Web services

XM

LXML

XM

L XML

XM

L

Enabled through XML

?

?

??

Web Services Enabled through XML

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Why Web Services? (1/3)

�Platform neutral

�Accessible in a standard way

�Accessible in an interoperable way

�Use simple and ubiquitous tools

�Relatively cheap

�Simplify enterprise integration



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� Interoperable – Connect across

heterogeneous networks using ubiquitous

web-based standards

�Economical – Recycle components, no

installation and tight integration of software

�Automatic – No human intervention required even for highly complex

transactions

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�Accessible – Legacy assets & internal

applications are exposed and accessible on the Web

�Available – Services on any device, anywhere, and anytime

�Scalable – No limits on scope of applications and amount of heterogeneous applications



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Impact of Web Services

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Myths about Web Services (1/2)

�Web Services are something completely new

�Web services is distributed computing all over again – only now it is based on the web

�Web services are XML-based

�You have to write Web Services from scratch

� Tools available for developing Web services, such as MS .NET, Apache Axis, J2EE, and Systinet



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�Web services require only SOAP, WSDL,

and UDDI

�We need more high-level semantics

�Web services are based on the RPC

paradigm

� Document-driven model would be more

popular communication model

�Web services must be based on HTTP

� Other transports such as SMTP can also be

used

Myths about Web Services (2/2)

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Agenda

�Web Technologies








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Amazon.com Web Service

� URL http://www.amazon.com/webservices

�What users can do

�Search for products and information about products, such as product comments

� Statistics

�More than 50,000 developers have registered to

request the ID for AWS

�Over 900,000 Web sites have joined Amazon.com

Associates

� Reference applications� Amazon Course Item for Blackboard 6

� OK Mall

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eBay Developers Program� URL http://developer.ebay.com/DevProgram/

�What users can do�Send a list of products to be sold

�View a list of products currently being sold

� Statistics (As of December 2005)�About 25,000 members who use eBay API

�About 1,900 applications call eBay API

�About 47% of eBay.com listings are thourgh eBay Web Services

�During Q4 2005, the eBay Platform handled more than 8 billion Web services requests, up from less than 1 billion for the entire year of 2002.

�The number of eBay Web Services transactions through APIs increased 84% annually

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Yahoo Developer Network

�URL http://developer.yahoo.com�What developers can do

� Use Yahoo! Maps APIs to point to or embed Yahoo! Mpas on their site to display locations and overlay data dynamically

� Use Flickr API to start building a photo sharing application

� Use Yahoo! Search APIs

� Use Yahoo! Widgets which are minature client applications that run within the Yahoo! Widget Engine

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Google Web APIs

�URL http://www.google.com/apis/

� Software developers can query billions of web pages directly from their own computer programs

� Google uses the SOAP and WSDL standards so a developer can program in his or her favorite environment - such as Java, Perl, or Visual Studio .NET

� To use Google Web APIs, users must

�Download the developer's kit

�Create a Google Web account

�Write a program using user’s license key

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Thailand: E-Revenue Web Services

�URL http://www.rd.go.th/webservice/

�Create service oriented organization by

providing professional services to

citizens to improve efficiency and

fairness in taxcollection

�Serve as a catalyst in driving e-services / e-commerce take up via business

partnership

�Sample services: PIN/TIN Verification

Info, VAT Refund for Tourist info

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Thailand: PTT Internet Web Services

�URL http://www.pttplc.com/pttinfo.asmx

�The users can get the information about oil price and news related to oil

�Support these five operations�GetOilPrice

�CurrentOilPrice

�GetNews

�CurrentNews

�CurrentOilPriceDS

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Search for Available Web Services�Web Services List and

� http://www.wsiam.com

� List of Web Services

� http://www.xmethods.com

�Web services diagnostics and testing

� http://www.mindreef.net

�Resources and services for SOAP

� http://www.soapclient.com/

� Free Web Services – Web Services List

� http://www.webservicex.net/WS/wscatlist.aspx

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Web Services Resources in Thailand

�Web Services Forum at KKU

� http://campus.en.kku.ac.th/campusboard

� Tutorials in Thai

� http://www.wsiam.com

�XML and Web Services Course at KKU� http://gear.kku.ac.th/~krunapon/178375

�Web Services Contest in National Software Const organized by NECTEC� http://www.hpcc.nectec.or.th/wiki/index.php/Web_Services_Contest



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Agenda

�Web Technologies




�Web Services Architecture and

Standards


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Web Services Architecture

1. Service Registers(Publish)

2. Client requestservice location

(Discover)

3. Client calls service(Bind)

UDDI Registry

Service Provider Service Client



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Operation Models for Web Services (1/3)

�Web Service Provider

�Creates the Web service typically as

SOAP-based service interfaces

�Deploys the service and makes them

available for invocation over a network

�Describes the Web service as a WSDL-based service description

�Registers the WSDL-based service

description with a service broker, which

is typically a UDDI registry

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�Registry

�Stores the service description as binding

templates and URLs to WSDLs located

in the service provider environment

�List various service types, descriptions,

and locations of the services that help

the service requesters find and

subscribe to the required services



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�Service Clients� Locates the required services by querying the UDDI registry

� Obtains the binding information and the URLs to identify the service provider

� Invokes the service provider

� Retrieves the WSDL Service description for those registered services

� Communicate with the service provider

� Exchange data or message by invoking the available services in the service container

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Web Services Interaction Diagram

Request WSDL location

UDDI

Registry1

Download WSDL WSDL

2

3

Web

Services

Send SOAP messages

with XML documents



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Web Services Standards

�XML (Extensible Markup Language)

�SOAP (Simple Object Access Protocol)

�WSDL (Web Services Description

Language)

�UDDI (Universal Description and

Discovery Integration)

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Extensible Markup Language

�Text-based Markup Language

�Markup is the extra information for describing and formatting data

�Standard language for exchanging and representing data on the Internet

�Both XML and HTML are markup languages�<b>NSC</b>

�<event>NSC</event>



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HTML vs. XML

�Language Purposes

�HTML tags are designed for indicating the format (Web browser)

Example: <b>NSC</b>

�XML tags are designed for describing data

Example: <event>NSC</event>

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Sample XML Document

<?xml version=“1.0”?>

<nation>

<name>Thailand</name>

<location>Southeast Asia</location>

</nation>



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Desirable Features of XML (1/2)

�Simple and extensible

� License-free

�Platform independent

� International language support

�Read and edit XML using any standard

text-editing tool

�Several applications and usage

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Desirable Features of XML (2/2)

�Easy data exchange

�Customizing Markup Languages

� ebXML (Electronic Business Markup Language)

�Self-describing

�Make automation of data processing possible

�Validation

� Apply semantic rules to specify the structure of document for validation



53

XML Applications

�System independent and vendor

independent

�Has metadata markup and is deliverable

via the Web

�There are style sheets for views and

transforms information

�XML enables integration of legacy

systems and new systems

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�SOAP (Simple Object Access Protocol)SOAP (Simple Object Access Protocol)SOAP (Simple Object Access Protocol)SOAP (Simple Object Access Protocol)


Language)





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What is SOAP?�SOAP stands for Simple Object Access Protocol

�SOAP is a lightweight protocol intended for exchanging structured information exchanging structured information exchanging structured information exchanging structured information

�SOAP uses XML technologies to define an extensible messaging frameworkextensible messaging frameworkextensible messaging frameworkextensible messaging framework

�The framework has been designed to be independent of any particular independent of any particular independent of any particular independent of any particular programming modelprogramming modelprogramming modelprogramming model and other implementation specific semantics

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What SOAP is Not

�Not a component model

� It will not replace objects and

components, i.e., EJB, JavaBeans

�Not a programming language

� It will not replace Java

�Not a solution for all

� It will not replace other distributed

computing technologies such as RMI



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SOAP Message Format

SOAP Message

…

Primary MIME part(text/xml)

Attachment

Attachment

Attachment

SOAP Envelope

SOAP Header

SOAP Body

Header Entry

Header Entry

…

Body Entry

Body Entry

…

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<?xml version="1.0" encoding="UTF-8"?>

<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:add<ns1:add<ns1:add<ns1:add soapenv:encodingStyle=

"http://schemas.xmlsoap.org/soap/encoding/" xmlns:ns1="http://localhost:8090/axis/Calcu

lator/Calculator.jws">

<ns1:arg0 xsi:type="xsd:int">2</ns1:arg0><ns1:arg0 xsi:type="xsd:int">2</ns1:arg0><ns1:arg0 xsi:type="xsd:int">2</ns1:arg0><ns1:arg0 xsi:type="xsd:int">2</ns1:arg0>

<ns1:arg1 xsi:type="xsd:int">3</ns1:arg1><ns1:arg1 xsi:type="xsd:int">3</ns1:arg1><ns1:arg1 xsi:type="xsd:int">3</ns1:arg1><ns1:arg1 xsi:type="xsd:int">3</ns1:arg1>

</ns1:add>

</soapenv:Body>



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<?xml version="1.0" encoding="UTF-8"?>

<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:addResponse soapenv:encodingStyle="http://schemas.xml

soap.org/soap/encoding/" xmlns:ns1="http://localhost:8090/ax

is/Calculator/Calculator.jws">

<ns1:addReturn xsi:type="xsd:int">5</ns1:addReturn><ns1:addReturn xsi:type="xsd:int">5</ns1:addReturn><ns1:addReturn xsi:type="xsd:int">5</ns1:addReturn><ns1:addReturn xsi:type="xsd:int">5</ns1:addReturn>

</ns1:addResponse></soapenv:Body>

</soapenv:Envelope>

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�WSDL (Web Services Description WSDL (Web Services Description WSDL (Web Services Description WSDL (Web Services Description

Language)Language)Language)Language)





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What is WSDL?

�WSDL stands for Web Services Description

Language

�XML language for describing web servicesXML language for describing web servicesXML language for describing web servicesXML language for describing web services

�XML service is described as

� A set of communication endpoints (ports)

�Endpoint is made of two parts

� Abstract definition of operations and messages

� Concrete binding to networking protocol and message format

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Why WSDL?

�Enable automation of communication

details between communicating partners

�Machines can read WSDL

�Machines can invoke a service defined in WSDL

�Discoverable through registry

�Arbitration

� 3rd party can verify if communication conforms to WSDL



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Language)

�UDDI (Universal Description and UDDI (Universal Description and UDDI (Universal Description and UDDI (Universal Description and

Discovery Integration)Discovery Integration)Discovery Integration)Discovery Integration)



65

What is UDDI?

�UDDI stands for Universal Description, Discovery and Integration

�Programmatic registration and discovery of business entities and their Web services

�Based on SOAP, HTML, and XML

�Registry data� Business registrations

� Service type definitions

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Available UDDI

�UDDI Browser

http://soapclient.com/uddisearch.html

� IBM UDDI Business Registry

https://uddi.ibm.com

�Microsoft UDDI

http://uddi.microsoft.com

�SAP UDDI

http://uddi.sap.com



67

Open Source Web Services Development

Tools

�Apache Axis

� http://ws.apache.org/axis

�PHP NuSOAP

� http://dietrich.ganx4.com/nusoap/index.php

�SUN J2EE: Java Technology and Web

Services

� http://java.sun.com/webservices/index.jsp

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Commercial Web Services Development Tools

� BEA WebLogic Web Service� http://dev2dev.bea.com//webservices

� Cape Clear � http://www.capeclear.com/

� IBM WebShpere Software� http://www-306.ibm.com/software/websphere/

� MS .NET� http://msdn.microsoft.com/webservices/

� Systinet� http://www.systinet.com/

� webMethods� http://www.webmethods.com



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Web Services Development Tools

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Web Servers

�Microsoft IIS

�Sun Application Server

�Apache

�Jarkata Tomcat

�Oracle

�Systinet Web Server

�JBoss

�BEA Weblogic Server



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Summary

�Web services technology exists for making different systems seamlessly work together

�XML is the language of exchange data

�Web service standards are open standards

�Web services have been developed and used extensively in many countries

� Thailand should develop and employ Web

services technology more for the benefits of

more effective management and business profits

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References� Web Services ABC

http://www.wsiam.com/document/abcwebservices/webservicesabc.jsp

� http://ws.cmsthailand.com/

� Amazon and eBay Web services usage statistics

http://www.itfacts.biz/index.php?id=P1340

� eBay Web Services Usage Statistics

http://blogs.zdnet.com/ITFacts/?p=10326� �� (�� )

http://www.ais.co.th/thai/news02.html

� Hugo Haas, W3C, “Designing the architecture for Web Services”, http://www.w3.org/2003/Talks/0521-hh-wsa/

� http://www.javapassion.com/webservices/

� http://www.microsoft.com/thailand

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