Building A SOAP Client With Visual C++

Building A SOAP Client With Visual C++ - Demonstrating a sample SOAP client
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For demonstrating the use of the SOAP classes that we've looked at in this article, I've used one of the services listed on http://www.xmethods.net/. The service indicates Yahoo Messenger's online presence. You can find the required details by following this URL. The only thing it expects is a method parameter i.e. the Yahoo user's login id. The result returned is a boolean value indicating 0 for offline and 1 for online. Other details are available on the site or by viewing the WSDL here.

Anyway, I guess the best way to learn something is to see the source code in action, so that's exactly what we will do now. Here's the C++ code for a console application that uses SOAP calls to find out if a Yahoo user is online:

#include

#import "msxml3.dll"
using namespace MSXML2;

#import "C:\Program Files\Common Files\MSSoap\Binaries\MSSOAP1.dll" \
exclude("IStream", "ISequentialStream", "_LARGE_INTEGER", \
"_ULARGE_INTEGER", "tagSTATSTG", "_FILETIME")

using namespace MSSOAPLib;

void main()
{
CoInitialize(NULL);

ISoapSerializerPtr Serializer;
ISoapReaderPtr Reader;
ISoapConnectorPtr Connector;

// Connect to the service
Connector.CreateInstance(__uuidof(HttpConnector));
Connector->Property["EndPointURL"] = "http://www.allesta.net:51110/webservices/soapx4/isuseronline.php";
Connector->Connect();

// Begin message
Connector->Property["SoapAction"] = "uri:allesta-YahooUserPing";
Connector->BeginMessage();

// Create the SoapSerializer
Serializer.CreateInstance(__uuidof(SoapSerializer));

// Connect the serializer to the input stream of the connector
Serializer->Init(_variant_t((IUnknown*)Connector->InputStream));

// Build the SOAP Message
Serializer->startEnvelope("","","");
Serializer->startBody("");
Serializer->startElement("isuseronline","uri:allesta-YahooUserPing","","m");
Serializer->startElement("username","","","");
Serializer->writeString("laghari78");
Serializer->endElement();
Serializer->endElement();
Serializer->endBody();
Serializer->endEnvelope();

// Send the message to the web service
Connector->EndMessage();

// Let us read the response
Reader.CreateInstance(__uuidof(SoapReader));

// Connect the reader to the output stream of the connector
Reader->Load(_variant_t((IUnknown*)Connector->OutputStream), "");

// Display the result
printf("Answer: %s\n", (const char *)Reader->RPCResult->text);
CoUninitialize();

}

As you can see, the code is fairly straight forward, and even if you haven't worked with C++ before, then I'm sure that you can figure out what the code does: Firstly, it connects to the remote server. Secondly, it creates the SOAP message and sends it. Lastly, it reads the response from the server and outputs it to the screen with printf.
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