Semantic web services

M I R G H A N I A H M E D

S U D A N U N I V E R S I T Y- W E B T E C H N O L O G Y

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Semantic Web Services

mirgani2008@yahoo.com - Sudan- 0917598234

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Outlines

What are web services?Why we use web services?The basics of web servicesSecuring web services.What’s next for web services?

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Definition

Web services are software applications that can be discovered, described, and accessed based on XML and standard Web protocols over intranets, extranets , and the Internet.

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Scenario of Web Services In Use

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Why We Use Web Services?

These questions are so fundamental that you should ask them about any candidate Technology: Do Web services solve real problems? Is there really a future for Web services? How can I use Web services?

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Basics of Web Services

This section gives a high-level overview of some of the basic Web services technologies: SOAP WSDL

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What Is SOAP?

SOAP used to stand for “Simple Object Access Protocol”.

SOAP is the envelope syntax for sending and receiving XML messages with Web services.

SOAP is the communication language of Web services.A SOAP message contains the following

elements:• A SOAP envelope that wraps the message• A description of how data is encoded• A SOAP body that contains the application-specific message that

the backend application will understand.

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Structure of a Web-based SOAP message

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What Is WSDL?

Stand of Web Service Definition Language.The W3C defines WSDL as “an XML format for

describing network services as a set of endpoints operating on messages containing either document-oriented or procedure oriented information.”

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WSDL process works

Dynamic communication by inspecting WSDL.

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How to Discover Web Services

if you would like to search for Web services based on the features they provide and then dynamically connect to them and use them, you will need a Web service registry.

two key registry technologies:• UDDI.• ebXML registries.

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What Is UDDI?

Universal Description, Discovery, and Integration is an evolving technology and is not yet a standard, but it is being implemented and embraced by major vendors.

UDDI is a phone book for Web services.allows you to discover Web services.

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UDDI Registry

A UDDI Registry as a conceptual phone book

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What Are ebXML Registries?

The ebXML standard was created by OASIS to link traditional data exchanges to business applications to enable intelligent business processes using XML.

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An ebXML Architecture

An ebXML architecture in use.

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Orchestrating Web Services

Orchestration is the process of combining simple web services to create complex, sequence-driven tasks.

A Simple Example:• For our example, we’ll list five separate Web services within a

fictional organization: Hotel finder Web service. Driving directions finder. Airline ticket booker. Car rental Web service. Expense report creator.

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An Orchestration

An orchestration example.

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Securing Web Services

One of the biggest concerns in the deployment of Web services today is security.

One of the reasons that many system integrators appreciate Web services is that SOAP rides on a standard protocol.

List basic terms that are related to Web services security:• Authentication.• Authorization.• Single sign-on (SSO).• Confidentiality.• Integrity.• Non repudiation.

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Protection scenario

Protection at every point

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Other Security Types

XML Signature

XML Signature is a W3C Recommendation that provides a means to validate message integrity and non-repudiation. With XML Signature, any part of an XML document can be digitally signed.

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XML Encryption

XML Encryption is a technology and W3C Candidate Recommendation that handles confidentiality; it can hide sensitive content, so that only the intended recipient can read the sensitive information.

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What’s Next for Web Services?

As Web services evolve, there is great potential in two major areas:

Grid-Enabled Web Services:

Grid computing is a technology concept that can achieve flexible, secure, and coordinated resource sharing among dynamic collections of individuals, institutions , and resources.

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A Semantic Web of Web Services:The Semantic Web and Web services go hand in hand.

XML, a self-describing language, is not enough. WSDL, a language that describes the SOAP interfaces to Web services, is not enough. Automated support is needed in dealing with numerous specialized data formats.

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Summary

Defining web services. Basic technologies of web services.Orchestration.Security in web services.A vision of where we believe web services will be

tomorrow.

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References

The Semantic Web:A Guide to the Future of XML, Web Services, and Knowledge Management.

Dieter Fensel , “Semantic Enabled Web Services,” XML-Web Services ONE Conference, June 7,2002.

Foster, Kesselman , Tuecke , “The Anatomy of the Grid: Enabling Scalable Virtual Organizations,” International J. Supercomputer Applications 15, no.3, (2001).

Kevin T. Smith, “Solutions for Web Services Security.Bruce Schneier, “Cryptogram Monthly Newsletter,” February 15,

2002, http://www.counterpane.com