Web Service Definition Language: Sample HelloWorld WSDL

The Web Services Description Language is an XML-based language that is used for describing the functionality offered by a Web service. A WSDL description of a web service (also referred to as a WSDL file) provides a machine-readable description of how the service can be called, what parameters it expects, and what data structures it returns. It thus serves a roughly similar purpose as a method signature in a programming language.

Assuming the service provides a single publicly available function, called sayHello. This function expects a single string parameter and returns a single string greeting. For example if you pass the parameter world then service function sayHello returns the greeting, “Hello, world!”.

HelloWorld WSDL file:

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<definitions name="HelloService"    targetNamespace="http://www.examples.com/wsdl/HelloService.wsdl"    xmlns="http://schemas.xmlsoap.org/wsdl/"    xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"    xmlns:tns="http://www.examples.com/wsdl/HelloService.wsdl"    xmlns:xsd="http://www.w3.org/2001/XMLSchema">      <message name="SayHelloRequest">       <part name="firstName" type="xsd:string"/>    </message>    <message name="SayHelloResponse">       <part name="greeting" type="xsd:string"/>    </message>      <portType name="Hello_PortType">       <operation name="sayHello">          <input message="tns:SayHelloRequest"/>          <output message="tns:SayHelloResponse"/>       </operation>    </portType>      <binding name="Hello_Binding" type="tns:Hello_PortType">    <soap:binding style="rpc"       transport="http://schemas.xmlsoap.org/soap/http"/>    <operation name="sayHello">       <soap:operation soapAction="sayHello"/>       <input>          <soap:body             encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"             namespace="urn:examples:helloservice"             use="encoded"/>       </input>       <output>          <soap:body             encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"             namespace="urn:examples:helloservice"             use="encoded"/>       </output>    </operation>    </binding>      <service name="Hello_Service">       <documentation>WSDL File for HelloService</documentation>       <port binding="tns:Hello_Binding" name="Hello_Port">          <soap:address             location="http://www.examples.com/SayHello/">       </port>    </service> </definitions>

Analysis of the Example:

• Definition : HelloService
• Type : Using built-in data types and they are defined in XMLSchema.
• Message :
  • sayHelloRequest : firstName parameter
  • sayHelloresponse: greeting return value
• Port Type: sayHello operation that consists of a request and response service.
• Binding: Direction to use the SOAP HTTP transport protocol.
• Service: Service available at http://www.examples.com/SayHello/.
• Port: Associates the binding with the URI http://www.examples.com/SayHello/ where the running service can be accessed.

In next post i’ll explain on how to deploy sample WSDL in Eclipse environment.

Ref: http://www.tutorialspoint.com/wsdl/wsdl_example.htm