Question

Recently I’ve been experiencing a nightmare with .NET (C#) and SOAP Transmissions.
I’ve got to consume a webservice (which was supposed to be an easy task) but it become terrible and nothing seem to works.

HttpWebRequest webRequest = (HttpWebRequest)System.Net.WebRequest.Create("http://api.myapi.com/apis/services/theapi");

webRequest.AllowAutoRedirect = true;
webRequest.Timeout = 1000 * 30;
webRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)";
webRequest.PreAuthenticate = true;
webRequest.Method = "POST";
webRequest.Headers.Add("SOAPAction: \"\"");
webRequest.Accept = "text/xml";

WebResponse webResponse = null;

try
{
    webResponse = webRequest.GetResponse();

    Stream Stream = webRequest.GetRequestStream();
    string SoapEnvelope = "<soap:Envelope>...SOAP CODE ...</soap:Envelope>";
    StreamReader streamReader = new StreamReader(webResponse.GetResponseStream(), System.Text.Encoding.UTF8);

    XmlDocument SoapEnvelopeXML = new XmlDocument();
    SoapEnvelopeXML.LoadXml(SoapEnvelope);

    SoapEnvelopeXML.Save(Stream);

    string result = streamReader.ReadToEnd();
    return result;
}

When I try to sniff the packages by using Wireshark, that’s what I get:

---- CLIENT INPUT ------
POST /apis/services/theapi HTTP/1.1
User-Agent: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)
SOAPAction: ""
Accept: text/xml
Host: api.myapi.com

Connection: Keep-Alive

---- SERVER ANSWER ------

HTTP/1.1 500 Internal Server Error
Date: Sat, 14 May 2011 15:35:32 GMT
X-Powered-By: Servlet 2.4; JBoss-4.0.5.GA (build: CVSTag=Branch_4_0 date=200610162339)/Tomcat-5.5
Content-Type: text/xml;charset=ISO-8859-1
Content-Length: 225
Connection: close
X-Pad: avoid browser bug

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><soap:Fault><faultcode>soap:Client</faultcode><faultstring>Error reading XMLStreamReader.</faultstring></soap:Fault></soap:Body></soap:Envelope>

As expected, since I haven’t posted a Soap Request (no XML in the request), I receive a SOAP Fault and ERROR 500.

Any ideas?

I’ve got to somehow do this manually. I’ve tried to use even TCPClient (to deal with it in a lower level), but all my attempts were frustrated.

Answer 1

You should use the VS Add Service Reference wizard to load the service into your project. The Add Service Reference generates classes to work with the api automatically at a much higher level, from the url of the service API endpoint. It will look something like this:

MyApiClient client = new MyApiClient();
MyApiResult result;

try {
    client.Open();
    result = client.CallMethod(param1, param2, ...);
    client.Close();
} catch (Exception ex) {
    // do something with FaultException or API error
}

// do something with the result returned, if needed

If you’ve done it correct, you shouldn’t have to deal with HttpWebRequest, explicit URL’s, or hand-typing out any SOAP XML at all!!