Web Services A New Internet Technology

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Web ServicesA New Internet Technology

• Kaj A. Jørgensen
• kaj_at_production.aau.dk
• Aalborg University, Dept. of Production, Denmark

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New Internet Technologies and Standards

• Web Services
• expose and describe itself to other applications
• can be located by other applications via
  directories
• can be invoked by using standard protocols
• XML based standards are currently available
• Simple Object Access Protocol (SOAP)
• Web Services Description Language (WSDL)
• Universal Description, Discovery, and Integration
  (UDDI) a standard for new ways to publish
  services
• conform to the basic request and response
  functionality
• supported by the World Wide Web Consortium (W3C)

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Create and Publish WS Query and Create WS
Clients
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Create and Publish WS Query and Create WS
Clients

• 1. Create and Publish a Web Service
• A Service Provider creates a service
• The service is defined in WSDL
• The service is published in a Service Directory
• 2. Query a Web Service
• A Service Client queries the directory
• The directory creates a reply
• The reply contains a WSDL descriptor of the
  service
• 3. Create a WS Client and Invoke the Service
• The Service Client invokes the service using the
  descriptor
• A SOAP message is structured, built and sent
• The Service Client receives and interprets the
  response

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Simple Object Access Protocol (SOAP)

• Lightweight protocol for exchange of information
• The protocol is XML based, simple and extensible
• The SOAP standard consists of three parts
• the SOAP envelope, what message and who should
  handle it
• the SOAP encoding rules, serialisation mechanisms
• the SOAP remote procedure call representation
• SOAP envelope is an XML document with
• SOAP header, optional
• SOAP body, the message body, a set of body entries

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Web Services Description Language (WSDL)

• XML format for describing Internet services
• Abstract description of network endpoints
• Messages document-oriented or procedure-oriented
  
• Types, data type definitions, e.g. with XSD
• Message, definition of the data being
  communicated
• Port Type, set of supported operations by one or
  more endpoints
• Binding, protocol and data format for a
  particular port type
• Port, single endpoint defined as binding and
  network address
• Service, a collection of related endpoints

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WS Application Area (example)

• Product Model Development Based on WS
• Service Providers react to problems and
  requirements
• development methodologies
• IT technologies, hardware, software, Internet
• the business must be profitable
• Product development services performed by experts
  on
• product model standards
• how to use modelling tools
• how to use analysis tools
• how to use visualisation hardware and software
• how to build structures of product property data
• how to exchange product model data

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WS Application Area (example)

• WS Based Development and Exchange
• Integrated server model, the foundation for WS
• Modelling tasks in cooperation with
• manufacturers
• suppliers
• consultancies
• building clients
• contractors
• New business area?
• is the right market trend there?
• the technology seems to be there
• the basic standards are available