overview of web services fan chen alvin mok ece1770 expert topic assignment
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Overview of Web Services
Fan Chen
Alvin Mok
ECE1770 Expert Topic Assignment
Outline
• What are Web Services & How Web Services Emerge
• Web Services Architecture&Operations• Web Services Core Protocols• Some Issues• Web Services and other Middleware
Platforms• Introduction to Microsoft .NET
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 W3C– A 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
How “Web Services” Emerge
• Web-based Applications Exploiting
• E-Business Urging the program-to-program interactions and and integration across heterogeneous platforms
• It came to the market at the time when demand for such technology was growing rapidly
• The existing middleware technologies were not implemented with the Web in mind
• It is backed by many key organizations (both commercial and non-commercial)
Web Services Standardization Bodies
• W3C:World Wide Web Consortium– the most notable web organization founded in 1994 by the
inventor of the web– Web Architecture, Document formats, interaction, etc
• OASIS: Organization of Structured Information Standards– Drives the development, convergence and adoption of e-
business standards– Service register and publish, Security, Transaction,etc
• WS-I: Web Services Interoperation Organization– Initiated by IBM, Microsoft and other vendors– Articulate/promote a common Web Services vision– Integrate specifications from various standards bodies
Web Services Basic Architecture
• Web services are consistent with established Service-Oriented Architecture(SOA) principles.
• Web Services Component– Service– Service Description
• Web services Roles– Service providers.– Service brokers– Service requestors.
• Web Services Operations– Publish– Find– Interact
The Conceptual Web Service Stacks
•Search and Find: UDDI
Universal Discovery Description and Integration, for registries of Web services
•Description: WSDL
Web Services Description Language, to describe networked XML-based services•Messaging: SOAP
•Simple Object Access Protocol, to define a uniform way of passing XML-encoded data.
•Transport: Internet Protocol,HTTP, STMP, etc.
•Format: XML,Extensible Markup Language, to define structures of documents
Operations and Message Flow
Some Issues
• Technology Areas to be Standardized– Security: Inter-enterprise communications secure (XKMS,
XACML,etc)– Business Process Management (WSFL)– Quality of Service and Reliable Messaging– System&Network Management
• Chaos: 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!
Web Services and Other Middleware Platforms-A Vision or Over-simplification?-
No one-size-fits-all solution!
Applicability-Examples
Web Interface Web Services
Secure Architecture with Firewall
Web Services
Legacy Component( other CORBA EJB)
CORBA
Mobile Environment/Thin Client
Web Services
Performance CORBA
Web Services and CORBA-A Possible Integration Scenario-
•SOAP request Generated
•Gateway maps WSDL to IDL, builds COBRA request and send to the server
•SOAP response is build out of the COBRA response
Web Services and Java
• Java community sees XML as complementary
– Java for algorithms, communications
– XML as a universal data interchange format
– Java API for XML:JAXP, JAX-RPC, JAXM, JAXR
– J2EE + Web Services Developer Pack
• Only for interoperation outside Java world
– JMS, RMI, RMI/IIOP between Java applications
-Thank You-
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