Web services encompass technologies for deploying and providing access to functionality over the web. Each web service is a self-contained, self-describing modular component that communicates using XML messages.

• Soap
• WSDL
• UDDI
• .NET

SOAP

The Simple Object Access Protocol (SOAP) is a lightweight protocol for exchange of information between diverse and distributed computing environments. It combines the extensibility and portability of XML with the ubiquitous web technology of HTTP. It provides a framework for defining how an XML message is structured using rich semantics for indicating encoding style, array structure, and data types. SOAP 1.1 was submitted as a W3C Note in May 2000 and SOAP 1.2 is now a W3C Working Draft.

SOAP 1.2 consists of:

• An envelope that defines a framework for describing what is in a message and how to process it.
• A transport binding framework for exchanging messages using an underlying protocol.
• A set of encoding rules for expressing instances of application-defined data types.
• A convention for representing remote procedure calls and responses.

Main sites and specifications

SOAP 1.1 - A W3C Note
http://www.w3.org/TR/SOAP/

The SOAP 1.2 W3C Working Draft consists of 2 parts:

SOAP Version 1.2 Part 1: Messaging Framework - describes the SOAP envelope and the SOAP transport binding framework
http://www.w3.org/TR/soap12-part1/

SOAP Version 1.2 Part 2: Adjuncts - describes the SOAP encoding rules the SOAP RPC convention and a concrete HTTP binding specification
http://www.w3.org/TR/soap12-part2/

Overviews and tutorials

WSDL

The Web Service Description Language (WSDL) can be used to describe a web service, providing a standard interface. A WSDL document is written in XML and describes a service as a set of endpoints, each consisting of a collection of operations. XML input and output messages are defined for each operation and their structure and data types are described using an XML Schema in the WSDL document. The WDSL and XML Schema provide a complete definition for the service interface, allowing programmatic access to the web service, in the manner of an API. Tasks like data requests or code execution can be performed by sending or receiving XML messages using, for example, SOAP.

Main sites and specifications

Web Services Description Language (WSDL) 1.1 - W3C Note
http://www.w3.org/TR/wsdl

Overviews and tutorials

UDDI

The Universal Description, Discovery and Integration (UDDI) specification defines a way to publish and discover information about web services. It is a collaboration between Ariba, IBM and Microsoft to speed interoperability and adoption of web services. The project includes a business registry (an XML document) and a set of operations on it. The registry can be used by programs to find and get information about web services and check compatibility with them, based on their descriptions. UDDI allows categorisation of web services so that they can be located and discovered and WSDL enables a programmatic interface to a service once it has been located.

Main sites and specifications

http://www.uddi.org/

Overviews and tutorials

Microsoft .NET Framework

The Microsoft .NET ("dotnet") Framework is a new platform, based on open Internet protocols and standards, for building integrated, service-oriented software applications. It features ease of development of web-based services, rich standard run-time services available to components written in a variety of programming languages, and inter-language and inter-machine interoperability.

Main sites and specifications

MSDN's .NET Home Page - Where Microsoft puts all of its most important .NET information, articles, samples, and links.
http://msdn.microsoft.com/NET/default.asp

Microsoft's GotDotNet Page - A community Web site, written by and maintained by the Microsoft .NET Framework Web Team.
http://www.gotdotnet.com/

Overviews and tutorials

The Semantic Web