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CurrencyConvertor: How to Use gSOAP and Webservices, Part One

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23 Mar 2007CPOL4 min read 556.6K   4.2K   71   160
How to auto-generate VC++ source and include it in your project

Introduction

In this article, I explain how to build a web service client from a WSDL file. I am releasing this project to help those who wish to begin to use a web service with gSOAP. I won't, however, be explaining about XML Serialization, Transient Types, Memory Management, etc.

I split the article into two parts for easier learning and better understanding. In Part One, I will explain how to get the class from the WSDL file to be used in Visual C++ 6. In Part Two, I show you how to use the classes generated with gSOAP.

To begin, you will want:

  • gSoap Toolkit - Download gSoap Toolkit for Windows and unzip it in a directory. You can download it form various sites. I used the site SourceForge and I downloaded the last release: gsoap_win32_2.7.8c.zip
  • WSDL - Download the "WSDL Schema Location" and save it with a WSDL extension. I used this WSDL; you can use another like CryptoService, DotGetLocator, etc.

Info: I used a free web service from WebserviceX.NET. If their server is busy and you get the the error "service unavailable," see if it's working here. After downloading the file, you have to build a C++ class from the WSDL file. Go to the gSoap directory and open the bin sub-folder, something like this: D:\gsoap-win32-2.7\bin. Here, you find two executable files:

  • wsdl2h.exe allows you do bindings in a C/C++ header file (*.h) from the WSDL file you downloaded before. (intermediate header)
  • soapcpp2.exe allows you to build a class with C++ formatting from the intermediate header.

WSDL Importer: Generate the File with C++ Bindings

Copy the WSDL to this directory and run wsdl2h.exe like this:

wsdl2h -o WSCurrencyConv.h CurrencyConvertor.wsdl 

Sample use of wsdl2h

In the shell, you'll see some warning (ignore this) and at the end "To complete the process, compile with: soapcpp2 WSCurrencyConv.h". If all works fine, you'll see a new file in the directory that will be WSCurrencyConv.h (or the name you write at the command line).

N.B. You shouldn't have problems, but if you do, check the name and path you entered and try again.

gSOAP Compiler: Generate the Proxy and XML Serialization Routines in Source-code Format

Run soapcpp2.exe like this:

soapcpp2 -ID:\gsoap-win32-2.7\Import WSCurrencyConv.h

Sample use of soapcpp2

To run this executable, you need to set the path for the gSOAP import, something like this: D:\gsoap-win32-2.7\import. This is similar to what I did before with:

-ID:\gsoap-win32-2.7\Import

The second parameter is the file *.h you entered the first time with wsdl2h. If it works, you'll see in the last line "Compilation successful". Now in the directory, you'll see a few new files.

N.B. You shouldn't have problems, but if you do, check that the path for the import file exists. Otherwise, you can copy all the files in the import directory to the bin directory and try again.

The new files will be:

  • CurrencyConvertorSoap.ConversionRate.req.xml
  • CurrencyConvertorSoap.ConversionRate.res.xml
  • CurrencyConvertorSoap.nsmap
  • soapC.cpp
  • soapClient.cpp
  • soapClientLib.cpp
  • soapCurrencyConvertorSoapObject.h
  • soapCurrencyConvertorSoapProxy.h
  • soapH.h
  • soapServer.cpp
  • soapServerLib.cpp
  • soapStub.h

Using the Visual C++

Now you have all you want to begin deploying your application with Visual C++.

Include Self-generated Code into Visual C++ Projects:

  1. You need to include in your application the files below:
    • soapC.cpp
    • soapH.h
    • soapClient.cpp
    • soapStub.h
    • CurrencyConvertorSoap.nsmap
    • soapCurrencyConvertorSoapProxy.h
    • stdsoap2.h (This file in D:\gsoap-win32-2.7\import is the same for all the SW)
    • stdsoap2.cpp (This file in D:\gsoap-win32-2.7\import is the same for all the SW)
  2. Set the no precompiler header for the CPP files before:
    • Go to Project Settings (Alt-F7).
    • Change the Settings for all configurations.
    • Select the CPP file before adding to the project (soapC.cpp, soapClient.cpp, stdsoap2.cpp).
    • Go to the C++ tab, select the category "Precompiled headers" and select the radio button "Not using precompiled headers".
    VC++ settings
  3. Set the Namespace, select the file stdafx.cpp and include the file CurrencyConvertorSoap.nsmap with this line:
    • #include "CurrencyConvertorSoap.nsmap"
  4. Link Ws2_32.lib to the project for use the Windows Sockets 2 API:
    • Go to Project Settings (Alt-F7).
    • Change the Settings for all configurations.
    • Go to tab Link, category General, and add Ws2_32.lib to the Object/Library modules.
    VC++ settings

The project is ready to communicate with the WS. You have all the classes you need to begin.

N.B. You could get this warning (shown below), but don't worry and go ahead. This warning is derived from the self-generated class with gSOAP; gSOAP doesn't check the maximum characters.

Warning

Points of Interest

I read many books online. I find that there are numerous mistakes and that all the examples are unusable. These books may have all you want to know in order to pass a university test, but there is too much information to begin a project. Irritated, I did this project to let you to begin to write a WS client.

History

  • 20th March, 2007: Second release - Article update
  • 12th July, 2006: First release

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


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Comments and Discussions

 
GeneralRe: Not working behind Proxy Pin
Dr.Luiji19-Jul-10 1:53
professionalDr.Luiji19-Jul-10 1:53 
GeneralRe: Not working behind Proxy Pin
Binni shah19-Jul-10 6:10
Binni shah19-Jul-10 6:10 
GeneralRe: Not working behind Proxy Pin
Dr.Luiji19-Jul-10 21:07
professionalDr.Luiji19-Jul-10 21:07 
Generalmod_gsoap apache error Pin
amit_tare17-Apr-10 0:43
amit_tare17-Apr-10 0:43 
GeneralRe: mod_gsoap apache error Pin
Dr.Luiji9-Apr-10 3:32
professionalDr.Luiji9-Apr-10 3:32 
GeneralRe: mod_gsoap apache error Pin
Jipeng Tao9-May-10 21:50
Jipeng Tao9-May-10 21:50 
GeneralI have an error when getting the conversion rate. Pin
waleed8216-Aug-09 2:19
waleed8216-Aug-09 2:19 
GeneralRe: I have an error when getting the conversion rate. Pin
Dr.Luiji16-Aug-09 10:27
professionalDr.Luiji16-Aug-09 10:27 
Hi Waleed,

You can't retrieves host information corresponding to a host name from a host database, than you can try to use the ip directly.

More specific the gethostbyname not work. It was called into soap->fresolve at stdsoap2.cpp(3449) and it's inside the tcp_connect function. Debug this place to find your error.

Try to see the result about nslookup (nslookup www.webserviceX.NET --> must be 209.162.186.60). You cannot resolve this address name with gethostbyname than insert directly the IP addres inside the soap->peer.sin_addr and avoid to call the gethostbyname.

For a better way check the return code about gethostbyname and follow this gethostbyname Function[^].

keep me informed.

Dr.Luiji

Trust and you'll be trusted.

My Blog : The Code Is Art

GeneralRe: I have an error when getting the conversion rate. Pin
waleed8216-Aug-09 21:14
waleed8216-Aug-09 21:14 
AnswerRe: I have an error when getting the conversion rate. Pin
Dr.Luiji17-Aug-09 7:09
professionalDr.Luiji17-Aug-09 7:09 
QuestionHttps ceritification question Pin
Jenny_air31-Jul-09 4:28
Jenny_air31-Jul-09 4:28 
AnswerRe: Https ceritification question Pin
Dr.Luiji31-Jul-09 11:24
professionalDr.Luiji31-Jul-09 11:24 
GeneralRe: Https ceritification question Pin
Jenny_air31-Jul-09 16:26
Jenny_air31-Jul-09 16:26 
GeneralRe: Https ceritification question Pin
Dr.Luiji1-Aug-09 3:22
professionalDr.Luiji1-Aug-09 3:22 
GeneralgSOAP for TCP binding and callback events. Pin
BicycleTheif6-Jul-09 18:49
BicycleTheif6-Jul-09 18:49 
GeneralRe: gSOAP for TCP binding and callback events. Pin
Dr.Luiji6-Jul-09 22:26
professionalDr.Luiji6-Jul-09 22:26 
GeneralRe: gSOAP for TCP binding and callback events. Pin
BicycleTheif8-Jul-09 20:59
BicycleTheif8-Jul-09 20:59 
GeneralRe: gSOAP for TCP binding and callback events. Pin
Dr.Luiji9-Jul-09 1:48
professionalDr.Luiji9-Jul-09 1:48 
GeneralgSOAP proxy for WCF server with TCP binding and callback events Pin
BicycleTheif6-Jul-09 18:45
BicycleTheif6-Jul-09 18:45 
Questionavoiding the namespace binding in all the method calls??? Pin
naveen_naik17-Dec-08 2:13
naveen_naik17-Dec-08 2:13 
AnswerRe: avoiding the namespace binding in all the method calls??? Pin
Dr.Luiji17-Dec-08 11:43
professionalDr.Luiji17-Dec-08 11:43 
GeneralIgnoring certificate errors using SOAP in Visual C++ 6. Pin
Wahaj Khan3-Dec-08 20:30
Wahaj Khan3-Dec-08 20:30 
GeneralRe: Ignoring certificate errors using SOAP in Visual C++ 6. Pin
Dr.Luiji3-Dec-08 21:03
professionalDr.Luiji3-Dec-08 21:03 
GeneralRe: Ignoring certificate errors using SOAP in Visual C++ 6. Pin
Wahaj Khan4-Dec-08 2:20
Wahaj Khan4-Dec-08 2:20 
AnswerRe: Ignoring certificate errors using SOAP in Visual C++ 6. Pin
Renata3-Dec-08 21:49
Renata3-Dec-08 21:49 

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