Understanding Web services
The VAST Web services architecture is a framework that enables e-business services to be described, published, discovered, and invoked dynamically in a distributed computing environment.
Web services
Web services are self-contained, modular applications that can be:
•Described using a service description language. The description language that is being endorsed by IBM is WSDL (Web services Description Language).
•Published by registering their descriptions and use policies with a well-known registry. The registry being endorsed by IBM is the UDDI (Universal Description, Discovery and Integration) registry.
•Found by sending queries to UDDI registry and receiving the binding details of the service(s) that fit the parameters of the query.
•Bound by using the information contained in the service description to create a callable service instance or proxy.
•Invoked over a network by using the information contained in the binding details of the service description.
•Composed with other services into new services and applications.
VAST Web services have focused on enhancing the ability of a Web service to be found, bound, invoked and composed, which provides a robust and extensible Web services platform that allows users to maintain the object paradigm when building Web services in VAST Platform.
Web services Components:
•Service This is the application being provided for use by requesters that fit the prerequisites specified by the Service Provider. Its implementation is deployed on a network accessible platform. It is described through a service description language. Its description and access policies have been published to a registry.
•Service Provider From a business perspective, this is the owner of the service. From an architectural perspective, this is the platform that provides access to the service.
•Service Registry This is a searchable repository of service descriptions where service providers publish their services and service requesters find services and obtain binding information for services.
•Service Requestor From a business perspective, this is the business that requires certain function to be fulfilled. From an architectural perspective, this is the application or client that is looking for and invoking a service.
Web services Operations:
•Publish/Unpublish Service Providers advertise (publish) the availability of their e-business service to one or more service registries, or remove the advertisement of (unpublish) their service.
•Find Service Requestors interact with one or more service registries to discover a set of services that it can interact with to provide a solution.
•Bind Service Requestors negotiate with Service Providers to access and invoke e-business services.
Technologies Used
•Extensible Markup Language (XML)
A flexible framework for organizing ans sharing data. (see http://www.w3.org/XML)
A flexible framework for organizing ans sharing data. (see http://www.w3.org/XML)
•Web Services Description Language (WSDL)
an XML based interface definition language for network based services. WSDL specifies teh public interface of a Web service. (see http://www.w3.org/TR/wsdl)
an XML based interface definition language for network based services. WSDL specifies teh public interface of a Web service. (see http://www.w3.org/TR/wsdl)
•Simple Object Access Protocol (SOAP)
An XML based protocol for the exchange of information in a decentralized distributed environment. It is most commonly used to make remote procedure calls (RPSc) transported via HTTP. (see http://www.w3.org/TR/soap)
An XML based protocol for the exchange of information in a decentralized distributed environment. It is most commonly used to make remote procedure calls (RPSc) transported via HTTP. (see http://www.w3.org/TR/soap)
•Universal Description Discovery and Integration (UDDI)
A standards based architecture specification for service description. It is used to publish and find web services. (see http://uddi.xml.org/)
A standards based architecture specification for service description. It is used to publish and find web services. (see http://uddi.xml.org/)
Last modified date: 02/12/2021