Web Services for Enterprise Application · PDF fileWeb Services for Enterprise Application...
Transcript of Web Services for Enterprise Application · PDF fileWeb Services for Enterprise Application...
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