A WSDL document is, at its simplest, a collection of elements contained
within a root definition
element. These elements describe a service
and how an endpoint implementing that service is accessed.
A WSDL document has two distinct parts:
A logical part that defines the service in implementation neutral terms
A concrete part that defines how an endpoint implementing the service is exposed on a network
The logical part of a WSDL document contains the types
, the message
,
and the portType
elements. It describes the service’s interface and the messages exchanged
by the service. Within the types
element, XML Schema is used to define the structure of the data that makes
up the messages. A number of message
elements are used to define the structure of the messages
used by the service. The portType
element contains one or more operation
elements that define the messages sent by the operations exposed by the service.
The concrete part of a WSDL document contains the binding
and the
service
elements. It describes how an endpoint that implements the service connects to the outside world. The
binding
elements describe how the data units described by the message
elements are mapped into a concrete, on-the-wire data format, such as SOAP. The service
elements
contain one or more port
elements which define the endpoints implementing the service.