Chapter 1: Understanding Adaptive Server Enterprise Web Services

WSDL

A WSDL document is written in XML and describes a Web service. In addition to specifying the location of the Web service, a WSDL description also specifies the methods provided by the Web service, and the messages, datatypes, and communication protocols used by the Web service with the following tags:

<service> – defines the name of the Web service. For example, a Web service called ExecuteStoredProcService could be named as follows:
```
 <wsdl:service name="ExecuteStoredProcService">
  <wsdl:port binding="impl:aseSoapBinding" name="ase">
   <wsdlsoap:address location="http://myserver:8181/services/ase"/>
  </wsdl:port>
 </wsdl:service>
```
A WSDL document may contain one or more <service> tags. In the case of the Web Services Producer, there is only one service, which is named “ase.”
<binding> – defines the communication protocols used. The following example uses the SOAP protocol:
```
 <wsdl:binding name="aseSoapBinding" type="impl:ExecuteStoredProc">
...
 </wsdl:binding>
```
WSDL also supports use of HTTP and MIME protocols.

<port> – specifies the Web service address. For example:

  <wsdl:port binding="impl:aseSoapBinding" name="ase">
   <wsdlsoap:address location="http://myserver:8181/services/ase"/>
  </wsdl:port>

The <port> tag has attributes for name and binding.

<message> – defines the messages used. For example:

 <wsdl:message name="executeRequest">
  <wsdl:part name="service" type="xsd:string"/>
  <wsdl:part name="userName" type="xsd:string"/>
  <wsdl:part name="password" type="xsd:string"/>
  <wsdl:part name="sqlxOptions" type="xsd:string"/>
  <wsdl:part name="sql" type="xsd:string"/>
 </wsdl:message>

This is a request message for a method called executeRequest. The <part> tags correspond to parameter values for the method call in a request message and to return values in a response.

<operation> – associates a message with a Web method request or response. For example:

  <wsdl:operation name="execute" parameterOrder="service userName
   password sqlxOptions sql">
   <wsdl:input message="impl:executeRequest" name="executeRequest"/>
   <wsdl:output message="impl:executeResponse" name="executeResponse"/>
  </wsdl:operation>

<portType> – defines the methods provided. The <operation> tag is a child element of <portType>. For example:

 <wsdl:portType name="ExecuteStoredProc">
  <wsdl:operation name="execute" parameterOrder="aseServerName asePortNumber
....
  </wsdl:operation>
 </wsdl:portType>

<types> – defines the datatypes used. WSDL uses XML schema syntax to define datatypes.

WSDL is usually automatically generated by the Web Services Producer component and can be viewed in a Web browser at the following location:

http://myserver:producer_port/services/ase?wsdl

where myserver is the name of the host on which the Web Services Producer component is running, and producer_port is the port number.

View this book as PDF