What Is WSDL

PHP Tutorials - Herong's Tutorial Examples

∟SOAP Extension Function and Calling Web Services

∟What Is WSDL

This section describes what is WSDL - an XML based standard designed to describes protocol bindings and message formats of Web services.

What Is WSDL? WSDL (Web Services Definition Language) is an XML based standard designed to describes protocol bindings and message formats of Web services. WSDL is often pronounced as "Whiz-Dull".

A WSDL document is an XML document written in WSDL to describe Web service. Here is a copy of the WSDL document for the demonstration Web service used in previous sections. You can download one yourself by going to http://herongyang.com/Service/Hello_WSDL_11_SOAP.wsdl with your Web browser:

<?xml version="1.0"?>
<wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
  xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
  xmlns:hy="https://www.herongyang.com/Service/"
  targetNamespace="https://www.herongyang.com/Service/">

  <wsdl:documentation>
    Hello_WSDL_11_SOAP.wsdl
    Copyright (c) 2009 HerongYang.com. All Rights Reserved.
    All rights reserved
  </wsdl:documentation>

  <wsdl:types>
    <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
      targetNamespace="https://www.herongyang.com/Service/">
      <xsd:element name="HelloRequest" type="xsd:string"/>
      <xsd:element name="HelloResponse" type="xsd:string"/>
    </xsd:schema>
  </wsdl:types>

  <wsdl:message name="helloInputMessage">
    <wsdl:part name="helloInputPart" element="hy:HelloRequest"/>
  </wsdl:message>
  <wsdl:message name="helloOutputMessage">
    <wsdl:part name="helloOutputPart" element="hy:HelloResponse"/>
  </wsdl:message>

  <wsdl:portType name="helloPortType">
    <wsdl:operation name="Hello">
      <wsdl:input name="helloInput"
        message="hy:helloInputMessage"/>
      <wsdl:output name="helloOutput"
        message="hy:helloOutputMessage"/>
    </wsdl:operation>
  </wsdl:portType>

  <wsdl:binding name="helloBinding" type="hy:helloPortType">
    <soap:binding transport="http://schemas.xmlsoap.org/soap/http"/>
    <wsdl:operation name="Hello">
      <soap:operation
        soapAction="https://www.herongyang.com/Service/Hello"/>
      <wsdl:input name="helloInput">
        <soap:body use="literal"/>
      </wsdl:input>
      <wsdl:output name="helloOutput">
        <soap:body use="literal"/>
      </wsdl:output>
    </wsdl:operation>
  </wsdl:binding>

  <wsdl:service name="helloService">
    <wsdl:port name="helloPort" binding="hy:helloBinding">
      <soap:address
location="https://www.herongyang.com/Service/Hello_SOAP_11.php"/>
    </wsdl:port>
  </wsdl:service>

</wsdl:definitions>

I cannot read this document well before learning the WSDL specifications. But it seems to be describing precisely how this Web service should be used. See my other book: "SOAP Web Service Tutorials - Herong's Tutorial Examples" for more information on SOAP and WSDL.