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: