Calling an RPC Method Based Web Service

WSDL Tutorials - Herong's Tutorial Examples - Version 2.03, 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 by Dr. Herong Yang, 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 9
...
Stack trace:
#0 C:\herong\GetExchangeRate_Client.php(9): 
   SoapClient->SoapClient('http://www.hero...')
#1 {main} thrown in C:\herong\GetExchangeRate_Client.php on line 9

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

WSDL 20 Programming APIs and Testing Tools

Introduction to WSDL 1.1

WSDL 1.1 Document Structure and Syntax

WSDL 1.1 Binding Extension for SOAP 1.1

soapUI 3.0.1 - Web Service Testing Tool