Web Services Discovery
Encyclopedia
Web services provide access to software systems over the Internet using standard protocols. In a minimalistic scenario there exists at least a Web service provider that publishes some service such as a weather service and a Web service consumer that uses this service. Web service discovery is the process of finding a suitable Web service for given task.
Publishing a Web service involves at the bare minimum to create the software artifact and make it accessible to potential consumers. In order that a consumer can use a service, providers usually augment a Web service endpoint with an interface description using the Web Services Description Language
(WSDL).
Optionally a provider can explicitly register a service with a Web services registry such as UDDI or publish additional documents intended to facilitate discovery such as Web Services Inspection Language
(WSIL) documents. The service users or consumers need to search Web services manually or automatically. The implementation of UDDI servers and WSIL engines should provide simple search APIs or web-based GUI
to help find Web services.
Web services may also be discovered using multicast
mechanisms like WS-Discovery, thus reducing the need for centralized registries in smaller networks.
Publishing a Web service involves at the bare minimum to create the software artifact and make it accessible to potential consumers. In order that a consumer can use a service, providers usually augment a Web service endpoint with an interface description using the Web Services Description Language
Web Services Description Language
The Web Services Description Language is an XML-based language that is used for describing the functionality offered by a Web service. A WSDL description of a web service provides a machine-readable description of how the service can be called, what parameters it expects and what data structures...
(WSDL).
Optionally a provider can explicitly register a service with a Web services registry such as UDDI or publish additional documents intended to facilitate discovery such as Web Services Inspection Language
Web Services Inspection Language
WS-Inspection is a Web service specification for "discovery documents" developed in a joint effort by Microsoft and IBM. WS-Inspection lists groups of web services and their endpoints in an XML format. Currently, other standards are being used for this purpose, such as Microsoft's DISCO...
(WSIL) documents. The service users or consumers need to search Web services manually or automatically. The implementation of UDDI servers and WSIL engines should provide simple search APIs or web-based GUI
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
to help find Web services.
Web services may also be discovered using multicast
Multicast
In computer networking, multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source creating copies automatically in other network elements, such as routers, only when the topology of the network requires...
mechanisms like WS-Discovery, thus reducing the need for centralized registries in smaller networks.
Federated Discovery
The current UDDI search mechanism can only focus on a single search criterion, such as business name, business location, business category, or service type by name, business identifier, or discovery URL. In fact, in a business solution, it is very normal to search multiple UDDI registries or WSIL documents and then aggregate the returned result by using filtering and ranking techniques. IBM modularized this federated Web services discovery engine in 2001. The released technology from IBM is Business Explorer for Web Services (BE4WS).External links
- Research Paper: Investigating Web Services on the World Wide Web, 2008
- IBM Article: Aggregate UDDI searches with Business Explorer for Web services, 01 Mar 2002
- Research Paper: Discovery of Web Services in a Federated Registry Environment, 2004
- Survey Paper: Web Service Discovery Mechanisms: Looking for a Needle in a Haystack?, 2004