A WSDL document is just a simple XML document.
It contains a series of definitions describing a web service.
WSDL document structure
The WSDL document uses these main elements to describe a web service:
| Elements | Definition |
|---|
| <portType> | Operations performed by web service |
| <message> | Messages used by web service |
##<types> | Data types used by web service |
<binding> | Communication protocol used by web service |
The main structure of a WSDL document is similar to this:
<definitions>
<types>
data type definitions.......
</types>
<message>
definition of the data being communicated....
</message>
<portType>
set of operations......
</portType>
<binding>
protocol and data format specification....
</binding>
</definitions>
WSDL documents can contain other elements, such as extension elements, and A service element that combines the definitions of several web services into a single WSDL document. The
WSDL port
<portType> element is the most important WSDL element.
It can describe a web service, operations that can be performed, and related messages.
The <portType> element can be compared to a function library (or a module, or a class) in a traditional programming language.
WSDL message
<message> element defines the data element of an operation.
Each message consists of one or more components. These components can be compared to the parameters of a function call in a traditional programming language.
WSDL types
##<types> The element defines the data types used by the web service.
For maximum platform neutrality, WSDL uses XML Schema syntax to define data types.
WSDL Bindings##<binding> elements define the message format and protocol details for each port.
WSDL Example
This is a simplified fragment of a WSDL document:
<message name="getTermRequest">
<part name="term" type="xs:string"/>
</message>
<message name="getTermResponse">
<part name="value" type="xs:string"/>
</message>
<portType name="glossaryTerms">
<operation name="getTerm">
<input message="getTermRequest"/>
<output message="getTermResponse"/>
</operation>
</portType>
In this example, the <portType> element defines "glossaryTerms" as the name of a port and "getTerm" as a operationThe name.
The operation "getTerm" has an input message named "getTermRequest", and an output message named "getTermResponse". The
<message> element defines the parts of each message, as well as the associated data type.
Compared with traditional programming, glossaryTerms is a function library, and "getTerm" is a function with the input parameter "getTermRequest" and the return parameter getTermResponse.
