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