Presentation on theme: "Overview of Web Services"— Presentation transcript:
1 Overview of Web Services ECE1770 Expert Topic AssignmentOverview of Web ServicesFan ChenAlvin Mok
2 OutlineWhat are Web Services & How Web Services EmergeWeb Services Architecture&OperationsWeb Services Core ProtocolsSome IssuesWeb Services and other Middleware PlatformsIntroduction to Microsoft .NET
3 What are “Web Services”? Web Services are evolving, middleware platform that facilitate program-to-program interactions.A service is a software entity that can be discovered and invoked by other software systems.Definition from standardization body W3CA Web service is a software system identified by a URI, whose public interfaces and bindings are defined 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 messages conveyed by internet protocols
4 How “Web Services” Emerge Web-based Applications ExploitingE-Business Urging the program-to-program interactions and and integration across heterogeneous platformsIt came to the market at the time when demand for such technology was growing rapidlyThe existing middleware technologies were not implemented with the Web in mindIt is backed by many key organizations (both commercial and non-commercial)
5 Web Services Standardization Bodies W3C:World Wide Web Consortiumthe most notable web organization founded in 1994 by the inventor of the webWeb Architecture, Document formats, interaction, etcOASIS: Organization of Structured Information StandardsDrives the development, convergence and adoption of e-business standardsService register and publish, Security, Transaction,etcWS-I: Web Services Interoperation OrganizationInitiated by IBM, Microsoft and other vendorsArticulate/promote a common Web Services visionIntegrate specifications from various standards bodies
6 Web Services Basic Architecture Web services are consistent with established Service-Oriented Architecture(SOA) principles.Web Services ComponentServiceService DescriptionWeb services RolesService providers.Service brokersService requestors.Web Services OperationsPublishFindInteract
7 The Conceptual Web Service Stacks Format: XML,Extensible Markup Language, to define structures of documentsSearch and Find: UDDIUniversal Discovery Description and Integration, for registries of Web servicesDescription: WSDLWeb Services Description Language, to describe networked XML-based servicesMessaging: SOAPSimple Object Access Protocol, to define a uniform way of passing XML-encoded data.Transport: Internet Protocol,HTTP, STMP, etc.
9 Some Issues Technology Areas to be Standardized Security: Inter-enterprise communications secure (XKMS, XACML,etc)Business Process Management (WSFL)Quality of Service and Reliable MessagingSystem&Network ManagementChaos: There are tons of proposals from vendors but none of them has been universally accepted.Different implementation for core protocols: Commercial and open-source toolkits vary widely.A long way to go before web services cover the full range of requirements for e-business!
10 No one-size-fits-all solution! Web Services and Other Middleware Platforms -A Vision or Over-simplification?-No one-size-fits-all solution!
11 Applicability-Examples Web InterfaceWeb ServicesSecure Architecture with FirewallLegacy Component( other CORBA EJB)CORBAMobile Environment/Thin ClientPerformance
12 Web Services and CORBA -A Possible Integration Scenario- SOAP request GeneratedGateway maps WSDL to IDL, builds COBRA request and send to the serverSOAP response is build out of the COBRA response
13 Web Services and Java Java community sees XML as complementary Java for algorithms, communicationsXML as a universal data interchange formatJava API for XML:JAXP, JAX-RPC, JAXM, JAXRJ2EE + Web Services Developer PackOnly for interoperation outside Java worldJMS, RMI, RMI/IIOP between Java applications