DISCO

Summary

The two primary methods of publishing a Web service so that it can be discovered by others are UDDI and DISCO. UDDI is a central, highly structured directory service, and DISCO offers a free-form, browser-style discovery mechanism.

UDDI is a central repository for publishing technical specifications and company information, including services a company exposes over the Internet. Data published to UDDI includes information about the company as well as references to technical specifications.

UDDI is composed of registries and registrars. A company publishes its information to a single public registry via a SOAP-based API. The registry is then responsible for replicating the information to its peer registries. A company can also use an HTML interface provided by a registrar to manage its information within the UDDI directory.

The four primary datatypes are tModel, businessEntity, businessService, and bindingTemplate. UDDI provides an API for publishing and locating instances of these datatypes.

A tModel serves a dual purpose. First, you can use it to reference a technical specification such as a WSDL document, a transport protocol, or a workflow specification. Second, a tModel can reference a particular taxonomy used to categorize the information published within the directory.

A businessEntity is usually a company or a division within a company. It contains information such as the company address and contact information. It also contains information that categorizes the company, such as the particular industry.

A businessService is a collection of related services that a company exposes. A businessService is composed of a collection of bindingTemplate objects. A bindingTemplate describes a particular service, including the service's endpoint and the technical specifications the service supports.

Microsoft provides the UDDI SDK to facilitate developing UDDI-aware applications. The SDK contains a .NET object model to simplify interacting with a UDDI registry. It also contains the UDDI Developer Edition, a standalone registry that is installed locally and that fully supports the UDDI API.

DISCO is a lightweight mechanism for discovering Web services. It is used primarily for development by the Visual Studio .NET IDE. Visual Studio .NET automatically creates the necessary DISCO files. The DISCO file for a particular server is created at installation time; the DISCO file for a particular Web service is created along with the Visual Studio .NET project in which it is contained.