WebSphere Message Brokers
File: ac34640_
Writer: Jane Brockbank

Reference topic

This build: July 31, 2007 21:20:25

What is WSDL?

WSDL stands for Web Services Description Language and is an XML-based language that is defined by the World Wide Web Consortium (W3C) for describing an interface between applications. A WSDL definition tells a client how to compose a Web services request and describes the interface that is provided by the server.

Service

The WSDL document defines a service in terms of a number of:
  • ports (WSDL 1.1)
  • endpoints (WSDL 1.2)
These define where the service is available.

Ports (WSDL 1.1) or endpoints (WSDL 1.2)

Each named port or endpoint also defines a mechanism for accessing it: a binding. Each supported protocol has a separate binding. For example, SOAP over HTTP. Each binding refers to a named:
  • portType (WSDL 1.1)
  • interface (WSDL 1.2)

Bindings and portTypes (WSDL 1.1) or interfaces (WSDL 1.2)

  • A binding defines the message wire format and transport details.
  • A portType or interface is the logical interface to the Web service.

Both binding and portType or interface define operations.

Operations

Each operation comprises input and output elements that are defined in terms of messages or message parts.

The optional parameterOrder attribute is only applicable for RPC-style WSDL. The value of the parameterOrder attribute is an ordered list of WSDL message parts providing a hint to a Web service provider about how the parts map to a method signature.

Message elements

The message elements define a logical message in terms of one or more parts. Each part might correspond to a parameter on a method call.

A part is defined either as an XML Schema element or as an XML Schema type.

These elements and types are fully defined by either or both of the following:
  • A WSDL <types> section.
  • Imported schema (.xsd) files that provide the definitions for the WSDL part definitions.

Further information

For more information about WSDL 1.1 refer to the World Wide Web Consortium (W3C), and in particular the WSDL 1.1 document:
For more information about the WS-I Basic Profile refer to the WS-I, and in particular the WS-I Basic Profile document:
Related concepts
Message flows overview
WSDL validation
WSDL Version 1.1
WSDL and the application data structure
Related reference
WSDL operation types
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This build: July 31, 2007 21:20:25

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