Web Service Description Language, an XML based standard for
describing Web services, is used for locating a Web service regardless of the
underlying protocol that is being used. WSDL has been defined by W3C as
"an XML format for describing network services as a set of endpoints
operating on messages containing either document-oriented or procedure-oriented
information. The operations and messages are described abstractly, and then
bound to a concrete network protocol and message format to define an endpoint.
Related concrete endpoints are combined into abstract endpoints (services).
WSDL is extensible to allow description of endpoints and their messages
regardless of what message formats or network protocols are used to
communicate." Learn more on WSDL at Using
WSDL in SOAP applications.
A typical WSDL document describes the type description,
message description, port type, service description and the binding specification
details. The following sample shows the structure of an empty WSDL document.
Listing 2
<definitions>
<types>
definition of types
</types>
<message>
definition of messages
</message>
<portType>
definition of ports
</portType>
<binding>
definition of bindings
</binding>
</definitions>
