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.Net - Consuming webservice without WSDL

Asked 2011-05-23T11:59:19.040
9

We have a new accounting system that provides webservice interface to external clients. I want to access one of the interfaces but there's no WSDL so i created the request through the use of HttpWebRequest and it works fine.

However to ease the creation of the requests and parsing of the response i would like to create some kind of automapping function. I have the request and response structure in an XSD file. Any ideas?

Request creation:

public void SendRequest()
{
    HttpWebRequest request = CreateWebRequest();
    XmlDocument soapEnvelopeXml = new XmlDocument();
    soapEnvelopeXml.LoadXml(@"<?xml version=""1.0"" encoding=""utf-8""?>
        <soap:Envelope xmlns:soap=""http://schemas.xmlsoap.org/soap/envelope/"">
        <soap:Body xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance"" xmlns:xsd=""http://www.w3.org/2001/XMLSchema"">

            ++ structure type inserted here ++   

        </soap:Body>
        </soap:Envelope>");

    using (Stream stream = request.GetRequestStream())
    {
        soapEnvelopeXml.Save(stream);
    }

    using (WebResponse response = request.GetResponse())
    {
        using (StreamReader rd = new StreamReader(response.GetResponseStream()))
        {
            string soapResult = rd.ReadToEnd();
            Console.WriteLine(soapResult);
        }
    }
}
c# web-services xsd
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2 Answers

1

Well, if you really have no way of getting hold of a proper WSDL file but have XSD:s you could probably use the xsd.exe tool to create classes that map to your request and response types.

Something like this (run this in a Visual Studio Command Prompt)

xsd.exe TheRequest.xsd /c /n:Your.Namespace
xsd.exe TheResponse.xsd /c /n:Your.Namespace

But really, try your best to find that WSDL, it will make your life a lot easier..

answered 2011-05-23T12:31:49.217
1

I recommend that you Create a WSDL - reverse engineer it, and then produce your webservices client stubs from it.

The way to do it:

  1. Get a wire trace of the exact request and response the webservice uses. Use Fiddler or something similar.

  2. Build a WCF service, that approximates the request and response.

  3. Get the trace of that

  4. Compare (3) to (1). Remember you want XML infoset equivalence. Your namespace prefixes need not be the same, for example. Your namespaces need not be declared in the same location. But, the element names need to be exactly the same, and the xmlns strings need to be exactly the same. Modify the WCF service to more closely match the original. Restart it, go to step 3. Iterate as many times as it takes.

  5. point your WCF client to the real web service

  6. sit back and relax.

I've done this and it works. It can be tricky if you don't have insight into how DataContract attributes affect the XML on the wire. But as you play with it, you will gain the insight pretty quickly.

But how is it possible that it is a SOAP service and there is no WSDL on the service side? It might save you a ton of work to re-double your efforts to locate the real WSDL.

answered 2011-05-23T21:19:06.703

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