WEB SERVICES: THE NEW WAVE OF WEB SERVICES: THE NEW WAVE OF WEB TECHNOLOGYWEB TECHNOLOGY

Wafa Khorsheed, Eastern Michigan Wafa Khorsheed, Eastern Michigan UniversityUniversity

Asad Khailany, Eastern Michigan Asad Khailany, Eastern Michigan UniversityUniversity

OutlineOutline

I.I. IntroductionIntroduction

II.II. Definition Of Web ServicesDefinition Of Web Services

III.III. Web Services ArchitectureWeb Services Architecture

IV.IV. Web Service OperationsWeb Service OperationsV.V. Example Application Of Web Example Application Of Web

ServicesServices

VI.VI. WSDL Partial definition of WSDL Partial definition of GetCatalog ServiceGetCatalog Service

VII.VII. Benefits Of Web ServicesBenefits Of Web Services

IntroductionIntroduction Business organizations have embraced the Business organizations have embraced the

Internet and Web Technology as soon as they Internet and Web Technology as soon as they discovered the create value of the Web for discovered the create value of the Web for conducting business. conducting business.

The Internet presented incredible value and The Internet presented incredible value and reach for businesses of all sizes. reach for businesses of all sizes.

Great efficiencies, cost reduction and new Great efficiencies, cost reduction and new business opportunities have led the way for business opportunities have led the way for organization to use this technology. organization to use this technology.

This type of technology is commonly referred to This type of technology is commonly referred to as service-centric computing. Service-centric as service-centric computing. Service-centric application require the integration of many application require the integration of many collaborating applications on the Internet to collaborating applications on the Internet to achieve a business functionalityachieve a business functionality

Definition Of Web ServicesDefinition Of Web Services self-contained, self-describing, modular self-contained, self-describing, modular

applications that can be published, located, and applications that can be published, located, and invoked across the Web. invoked across the Web.

Web Services is any program that is callable by Web Services is any program that is callable by another program across the web in a another program across the web in a platform/language/object model independent platform/language/object model independent manner, using standard web protocols (XML, manner, using standard web protocols (XML, SOAP, WSDL, UDDI, etc.) SOAP, WSDL, UDDI, etc.)

There are three main uses of Web services. There are three main uses of Web services. Application integration Application integration Business integrationBusiness integration Commercial Web servicesCommercial Web services

Web Services ArchitectureWeb Services Architecture Service providers:Service providers: Provide services, and maintain a registry Provide services, and maintain a registry

that makes those services available. that makes those services available.

Service requestors:Service requestors: Work with service brokers to discover Work with service brokers to discover Web services, then invoke those services to create Web services, then invoke those services to create applications.applications.

Service brokers: Service brokers: they are the clearinghouses for services. they are the clearinghouses for services. Service brokers act as matchmakers between service Service brokers act as matchmakers between service providers and service requestors. The services broker is providers and service requestors. The services broker is referred to as UDDI (Universal Discovery, Description and referred to as UDDI (Universal Discovery, Description and Integration).Integration).

Web Service OperationsWeb Service Operations Publish/UnpublishPublish/Unpublish: Publishing and unpublishing : Publishing and unpublishing

involves advertising services to a registry (publishing) involves advertising services to a registry (publishing) or removing those entries (unpublishing). The service or removing those entries (unpublishing). The service provider contacts the service broker to publish or provider contacts the service broker to publish or unpublish a service.unpublish a service.

FindFind: The find operation is performed by service : The find operation is performed by service requestors and service brokers together. The service requestors and service brokers together. The service requestors describe the kinds of services they're requestors describe the kinds of services they're looking for, and the service brokers deliver the results looking for, and the service brokers deliver the results that best match the request. that best match the request.

BindBind: The bind operation takes place between the : The bind operation takes place between the service requestor and the service provider. The two service requestor and the service provider. The two parties negotiate as appropriate so the requestor can parties negotiate as appropriate so the requestor can access and invoke services of the provider.access and invoke services of the provider.

Web Services ArchitectureWeb Services Architecture

DB2

COBOLapp

z-Series Mainframe

WebS

phere w

ith EJB

s

Web ServicesRequestor

Windows 2000

Web app

server

COMapp

COMapp

CORBAapp

Web service Provider

SOAP Messages

WSDL

Web Services Broker(UDDI)

Example Application: Purchase Example Application: Purchase

OrderOrder Customer

Supplier

Carrier

Warehouse

GetCatalog()SendPO()GetPOStatus()GetInvoice()

ShipRequest()

ShipConfirm()

ShipOrder()

Bank

CheckAccBalance()

DebitAccount()

WSDL Partial definition of WSDL Partial definition of

GetCatalog ServiceGetCatalog Service <binding name="PartOrderingServiceBinding"<binding name="PartOrderingServiceBinding" type="GetCatalogServiceType">type="GetCatalogServiceType"> <soap:binding style="rpc" <soap:binding style="rpc"

transport="http://schemas.xmlsoap.org/soap/http"/>transport="http://schemas.xmlsoap.org/soap/http"/> <operation name="GetCatalog"><operation name="GetCatalog"> <soap:operation <soap:operation

soapAction="http://www.PartOrdering.com/GetCatalog"/>soapAction="http://www.PartOrdering.com/GetCatalog"/> <input><input> <soap:body type="InMessageRequest"<soap:body type="InMessageRequest" namespace="urn:PartOrdering"namespace="urn:PartOrdering" encoding="http://schemas.xmlsoap.org/soap/encoding/"/>encoding="http://schemas.xmlsoap.org/soap/encoding/"/> </input></input> <output><output> <soap:body type="OutMessageResponse"<soap:body type="OutMessageResponse" encoding="http://schemas.xmlsoap.org/soap/encoding/"/>encoding="http://schemas.xmlsoap.org/soap/encoding/"/> </output></output> </operation></operation></binding></binding>

Benefits Of Web Services Benefits Of Web Services

Promote interoperability:Promote interoperability: Enable just-in-time integration:Enable just-in-time integration: Reduce complexity through Reduce complexity through

encapsulation.encapsulation. Give new life to legacy Give new life to legacy

applications:applications: