Calling an RPC Method Based Web Service

WSDL Tutorials - Herong's Tutorial Examples - Version 2.10, by Dr. Herong Yang

WSDL Tutorials - Herong's Tutorial Examples

∟Calling an RPC Method Based Web Service

This section provides a tutorial example on how to write a PHP program to call an RPC method based Web service using the SoapClient class.

Ok, let's try to use the SoapClient class to call my RPC Web service, GetExchangeRate_WSDL_11_SOAP_11_RPC.wsdl, first.

Here is the example PHP program, GetExchangeRate_Client.php:

<?php 
# GetExchangeRate_Client.php
# Copyright (c) 2009 HerongYang.com, All Rights Reserved.
#
#- Loading the WSDL document
   $server = "http://www.herongyang.com/Service/";
   $wsdl = $server . "GetExchangeRate_WSDL_11_SOAP_11_RPC.wsdl";
   $client = new SoapClient($wsdl);

#- Calling the RPC method
   $result = $client->GetExchangeRate('USD', 'JPY', '2007-07-07');

#- Showing the result
   print "Exchange rate is: $result\n";
?>

Execution result of this example is presented below:

C:\herong\>\local\php\php GetExchangeRate_Client.php

PHP Fatal error:  SOAP-ERROR: Parsing WSDL: Unspecified encodingStyle
   in C:\herong\GetExchangeRate_Client.php on line 8
...
Stack trace:
#0 C:\herong\GetExchangeRate_Client.php(8): 
   SoapClient->SoapClient('http://www.hero...')
#1 {main} thrown in C:\herong\GetExchangeRate_Client.php on line 8

What's wrong here? The error message says, encodingStyle is not specified. Let's review the WSDL docuement:

  <wsdl:binding name="getExchangeRateBinding"
    type="hy:getExchangeRatePortType">
    <soap:binding transport="http://schemas.xmlsoap.org/soap/http"/>
    <wsdl:operation name="GetExchangeRate">
      <soap:operation style="rpc"
soapAction="http://www.herongyang.com/Service/getExchangeRate"/>
      <wsdl:input name="getExchangeRateInput">
        <soap:body use="encoded"
          parts="fromCurrencyPart toCurrencyPart datePart"/>
      </wsdl:input>
      <wsdl:output name="getExchangeRateOutput">
        <soap:body use="encoded" parts="ratePart"/>
      </wsdl:output>
    </wsdl:operation>
  </wsdl:binding>

The root cause of the problem is in <soap body ...> elements. I did not provide the encodingStyle="uri" attribute. The error above tells us that the SoapClient class needs encodingStyle="uri" if use="encoded" is used.

To fix the WSDL document is easy, just add encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" in <soap body ...> elements. But I am not going to fix it and keep it as is for testing purpose.

Conclusion, SoapClient class requires encodingStyle="uri", if use="encoded" is used. SoapClient class does not provide any default value to encodingStyle.

Last update: 2009.

Table of Contents

About This Book

Introduction to WSDL 2.0

WSDL 2.0 Document Structure and Syntax

WSDL Version 2.0 Part 2: Adjuncts

WSDL 2.0 Document Examples with SOAP Binding

Using WSDL Document in Java Apache Axis2/Java for WSDL

Apache Woden for WSDL Documents in Java

SoapUI - Web Service Testing Tool

PHP SOAP Extension for WSDL

Perl SOAP::Lite for WSDL