WSDL Invocation Tools, Part I - Page 4

Given the WSDL file in Example 6-1, you could manually create a SOAP client to invoke the service. A better alternative is to automatically invoke the service via a WSDL invocation tool. (See Figure 6-4.)

Figure 6-4. WSDL invocation tools

Many WSDL invocation tools already exist. This section provides a brief overview of three invocation tools.

GLUE

The Mind Electric provides a complete web service platform called GLUE (available at http://www.themindelectric.com/). The platform itself provides extensive support for SOAP, WSDL, and UDDI. Some of its advanced functionality, including support for complex data types, will be explored later in this chapter.

For now, you can try out the GLUE invoke command-line tool. Here is the command-line usage:

usage: invoke URL method arg1 arg2 arg3...

For example, to invoke the HelloService, make sure that your Apache Tomcat server is running, and place the HelloService.wsdl file within a publicly available directory. Then, issue the following command:

invoke http://localhost:8080/wsdl/HelloService.wsdl sayHello World

Once invoked, GLUE will immediately download the specified WSDL file, invoke the sayHello method, and pass World as a parameter. GLUE will then automatically display the server response:

Output:  result = Hello, World!

That's all there is to it!

GLUE also supports an excellent logging facility that enables you to easily view all SOAP messages. To activate the logging facility, set the electric.logging system property. The easiest option is to modify the invoke.bat file. The original file looks like this:

call java electric.glue.tools.Invoke %1 %2 %3 %4 %5 %6 %7 %8 %9

Modify the file to include the logging property via the -D option to the Java interpreter:

call java -Delectric.logging="SOAP" electric.glue.tools.Invoke %1 %2 %3 %4
    %5 %6 %7 %8 %9

When you invoke the HelloService, GLUE now generates the following output:

LOG.SOAP: request to http://207.237.201.187:8080/soap/servlet/rpcrouter
<?xml version='1.0' encoding='UTF-8'?>
<soap:Envelope 
   xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
   xmlns:xsd='http://www.w3.org/2001/XMLSchema'
   xmlns:soap='http://schemas.xmlsoap.org/soap/
   envelope/' xmlns:soapenc='http://schemas.xmlsoap.org/soap/encoding/' 
   soap:encodingStyle='http://schemas.xmlsoap.org/soap/encoding/'>
   <soap:Body>
      <n:sayHello xmlns:n='urn:examples:helloservice'>
         <firstName xsi:type='xsd:string'>World</firstName>
      </n:sayHello>
   </soap:Body>
</soap:Envelope>
 
LOG.SOAP: response from http://207.237.201.187:8080/soap/servlet/rpcrouter
<?xml version='1.0' encoding='UTF-8'?>
<SOAP-ENV:Envelope 
   xmlns:SOAP-ENV='http://schemas.xmlsoap.org/soap/envelope/'
   xmlns:xsi='http://www.w3.org/1999/XMLSchema-instance'
   xmlns:xsd='http://www.w3.org/1999/XMLSchema'>
   <SOAP-ENV:Body>
      <ns1:sayHelloResponse 
         xmlns:ns1='urn:examples:helloservice' 
         SOAP-ENV:encodingStyle=
            'http://schemas.xmlsoap.org/soap/encoding/'>
         <return xsi:type='xsd:string'>Hello, World!</return>
      </ns1:sayHelloResponse>
   </SOAP-ENV:Body>
</SOAP-ENV:Envelope>
 
result = Hello, World!

To view additional HTTP information, just set electric.logging to SOAP,HTTP.

SOAP::Lite for Perl

SOAP::Lite for Perl, written by Paul Kulchenko, also provides limited support for WSDL. The package is available at http://www.soaplite.com.

Example 6-2 provides a complete Perl program for invoking the HelloService.

Example 6-2: Hello_Service.pl

use SOAP::Lite;
 
print "Connecting to Hello Service...\n";
print SOAP::Lite
   -> service('http://localhost:8080/wsdl/HelloService.wsdl')
   -> sayHello ('World');

The program generates the following output:

Connecting to Hello Service...
Hello, World!

IBM Web Services Invocation Framework (WSIF)

Finally, IBM has recently released WSIF. The package is available at http://www.alphaworks.ibm.com/tech/wsif.

Much like GLUE, WSIF provides a simple command-line option for automatically invoking WSDL services. For example, the following command:

java clients.DynamicInvoker http://localhost:8080/wsdl/HelloService.wsdl
    sayHello World

generates the following output:

Reading WSDL document from 'http://localhost:8080/wsdl/HelloService.wsdl'
Preparing WSIF dynamic invocation
Executing operation sayHello
Result:
greeting=Hello, World!
 
Done!

Basic WSDL Example: HelloService.wsdl (cont.) - Page 3
Web Services Essentials
Basic WSDL Example: XMethods eBay Price Watcher Service - Page 5