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Web Services for Enterprise Application Integration

Liana RazmeritaProject Acacia, INRIA, Sophia-Antipolis

Outline

Web Services (WS)-IntroductionWhat is the technology associated with WS?How to deliver and operate WS?Why Web Services?What are Semantic Web services?

Service-oriented architectures (SOA)Conclusions

What are Web Services?A new generation of distributed, web-based technology 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. [Daconta et al., 2003]WS independent agents that produce and consume information, enabling automated business transactions. [Paolucci and Sycara, 2003]

How to deliver and operate WS?

A basic business transaction using web services consists of four stages:

Search ProvideSelect Pay?

Generic use case scenario

Service Requester

Service Provider

Service Registry

Find Publish

Bind

Communication Layer(protocols: HTTP, SMTP,..)

XML

Access (SOAP)

Describe (WSDL)

Discover (UDDI, ebXML, registries)

Layers of Web services

UDDI-Universal Description Discovery Integrationan application registry, similar to a telephone book

WSDL Web Service Description Language

SOAP Simple Object Access Protocol

XML-eXtended Markup Language

XML-eXtended Markup Language

HTML (Hypetext Markup Language) most common language on the WebXML is derived from SGML (Standard Generalized Markup Language)XML is a meta language for markup XML allows users to define their own tags

<h2>Out of the box</h2><i>by John Hagel</i>

…

<book><title>Out of the box</title>

<author>John Hagel</author>…

</book>

XML-eXtended Markup Language

XML standard recommended by W3CXML organize data in a hierarchyTag names can be chosenXML is an interoperable data format

SOAP”a lightweight protocol for exchange of information in a decentralized, distributed environment” W3C (http://www.w3.org/TR/soap/)WS communicate using SOAP, usually used with HTTP

HTTP Header

SOAP Envelope

SOAP Header

SOAP Body

SOAP messages<SOAP_ENV: Envelopexmlns:SOAP-ENV=http://schemas.xmlsoap.org/soap/envelope/SOAP-ENV:encodingStyle=http://schemas.xmlsoap.org/soap/encoding/”<SOAP-ENV:Body><m:GetLastTradePrice xmlns:m=”some URI”><symbol>DIS</symbol></m:GetLastTradePrice></SOAP-ENV:Body></SOAP-ENV:Envelope>

<SOAP_ENV: Envelopexmlns:SOAP-ENV=http://schemas.xmlsoap.org/soap/envelope/SOAP-ENV:encodingStyle=http://schemas.xmlsoap.org/soap/encoding/”<SOAP-ENV:Body><m:GetLastTradePrice Response xmlns:m=”some URI”><price>34</price></m:GetLastTradePrice Response></SOAP-ENV:Body></SOAP-ENV:Envelope>

How to describe Web services?

WSDL Web Service Description Language“WSDL is an XML format for describing network services as a set of endpoints operating on messages containing either document-oriented or procedure-oriented information.” W3C (http://www.w3.org/TR/wsdl)WSDL specification resulted from collaboration of IBM, Microsoft and Ariba.

How to discover Web Services?

UDDI-Universal Description Discovery Integration-not yet a standard, embraced by major vendors (http://www.uddi.org/)register public information about web services

Service description includesserviceName: textDescription of the service: provider:contactInformation: FOAF, VCardIOPE (Input Output Preconditions and Effects )….

Service-oriented architecture principlesSimplicity

simplicity at the end-points of the connections deliver functionality as a shared service

Loose couplingmodules connected through standard communication protocolsconnections across modules are loosely coupled

Heterogeneitya diversity of computing platforms and applications can communicate

Opennessubiquitous standards and protocols reduce concerns about lock-ins and maximize the returns on investments of the participants

WS major development directions

definition/granularity of a service discovery and invocation aspectscomposition and interoperation of services (manual, automatic and semi-automatic?)quality of services (trust, security)

Some companies working on SOA

Sun Microsystems’ Sun Labs (Java WSDP Developer Pack)

IBM (BPEL4WS Business Processes Execution Language, WSDL toolkit)Microfot (.Net)

SalesforceRightNowOblixSiebel Systems (SEBL)Ellison&Co (at Oracle)

Semantic Web Services

Web is evolving from a repository of Web resources towards a provider of services [McIlraithet al., 2001]W3C Semantic Web Interest Group: service description, choreography and specification of WSusing OWL_SOWL_S a semantic markup language formerlycalled DARPA Agent Markup Language for Services (DAML_S): the service profile, the service model, the service grounding

Semantic Web layered architecture

Semantic Web design and vision (Tim Berners-Lee,2001)

XML

RDF/RDFS

OWL (Ontology languages)

Logic layer

Proof layer

Alternatives to OWL_S

Web Service Modeling Framework (WSML)- Web Service Modeling Ontology (WSMO) Internet Reasoning Service (IRS-II) and (IRS-III) are Semantic Web Services Framework, developed by KMI,

Top level service ontology of OWL_S

Service

Service Profile

Service Grounding

Service Model

what it does

how to access it

how it works

A Web-service enabled architecture

Tomcat Server

Web Services

Servlet

service provider

service requester

Agents

ServerUDDI, registry

service requester

service query

WS for Enterprise Application Integration(EAI)

Ontologging projectA next generation of KMSs: ontologies, web services, user modeling and agents.

What are Knowledge Management Systems?Information systems dedicated to manage organizational knowledge. [Leidner and Alavi, 2001]

capitalize/store

sharecreate KMSs aim to integrate complex knowledge processes:

Collaboration between employees;Learning processes;Management of tacit knowledge;

WS for EAI Ontologging architecture

Multiple Ontology - &

Metadata Management

MS OfficeConnector

Query &Browsing Interface

Document Upload

Interface User Profile

Editor Ontologging Presentation

Layer

Multiple Ontology and

Metadata Management

UserManagement

(Profiling,Tracking )

DocumentManagement

& Indexer

Ontologging Core Integration Layer( Includes intelligent services , agents , ...)

Ontologging Middleware

Layer

Ontologging Storage

Layer

...

...

End Users

Admin -instration

ConclusionsA new generation of distributed, web-based technology

A new way to establish more flexible and low-cost connections across applications

WS architectures focus on connecting applications and data.

Authorized entities access data or applications regardless of location and technology platform.

WS enable to connect existing applications with the applications of their business partners.

References

Daconta, M, C., Obrst, L, J., Smith, K, T., 2003, The Semantic Web: A guide to the future of XML, Web Services and Knowledge Management, Wiley Publishing Inc. IndianaMake it simple-A survey of Information Technology, appeared in the Economist, October 30th, 2004.Curbera, F.; Duftler, M.; Khalaf, R.; Nagy, W.; Mukhi, N.; Weerawarana, S, Unraveling the Web services web: an introduction to SOAP, WSDL, and UDDI, Internet Computing, IEEE, Volume: 6, Issue: 2, March-April 2002, Pages:86 – 93Hagel, J., Out of the Box: Strategies for Achieving Profits Today and Growth Tomorrow through Web Services, 2002

Discussion

Questions and answersWork group session