How do I get access to SOAP response

Inspired by jfburdet, I wanted to see if it was possible to directly intercept at stream/byte level rather than reconstructing XML. And it is! See code below:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Web.Services.Protocols;
using System.Xml;

using Test.MyWebReference;

namespace Test {
    /// <summary>
    /// Adds the ability to retrieve the SOAP request/response.
    /// </summary>
    public class ServiceSpy : OriginalService {
        private StreamSpy writerStreamSpy;
        private XmlTextWriter xmlWriter;

        private StreamSpy readerStreamSpy;
        private XmlTextReader xmlReader;

        public MemoryStream WriterStream {
            get { return writerStreamSpy == null ? null : writerStreamSpy.ClonedStream; }
        }

        public XmlTextWriter XmlWriter {
            get { return xmlWriter; }
        }

        public MemoryStream ReaderStream {
            get { return readerStreamSpy == null ? null : readerStreamSpy.ClonedStream; }
        }

        public XmlTextReader XmlReader {
            get { return xmlReader; }
        }

        protected override void Dispose(bool disposing) {
            base.Dispose(disposing);
            DisposeWriterStreamSpy();
            DisposeReaderStreamSpy();
        }

        protected override XmlWriter GetWriterForMessage(SoapClientMessage message, int bufferSize) {
            // Dispose previous writer stream spy.
            DisposeWriterStreamSpy();

            writerStreamSpy = new StreamSpy(message.Stream);
            // XML should always support UTF8.
            xmlWriter = new XmlTextWriter(writerStreamSpy, Encoding.UTF8);

            return xmlWriter;
        }

        protected override XmlReader GetReaderForMessage(SoapClientMessage message, int bufferSize) {
            // Dispose previous reader stream spy.
            DisposeReaderStreamSpy();

            readerStreamSpy = new StreamSpy(message.Stream);
            xmlReader = new XmlTextReader(readerStreamSpy);

            return xmlReader;
        }

        private void DisposeWriterStreamSpy() {
            if (writerStreamSpy != null) {
                writerStreamSpy.Dispose();
                writerStreamSpy.ClonedStream.Dispose();
                writerStreamSpy = null;
            }
        }

        private void DisposeReaderStreamSpy() {
            if (readerStreamSpy != null) {
                readerStreamSpy.Dispose();
                readerStreamSpy.ClonedStream.Dispose();
                readerStreamSpy = null;
            }
        }

        /// <summary>
        /// Wrapper class to clone read/write bytes.
        /// </summary>
        public class StreamSpy : Stream {
            private Stream wrappedStream;
            private long startPosition;
            private MemoryStream clonedStream = new MemoryStream();

            public StreamSpy(Stream wrappedStream) {
                this.wrappedStream = wrappedStream;
                startPosition = wrappedStream.Position;
            }

            public MemoryStream ClonedStream {
                get { return clonedStream; }
            }

            public override bool CanRead {
                get { return wrappedStream.CanRead; }
            }

            public override bool CanSeek {
                get { return wrappedStream.CanSeek; }
            }

            public override bool CanWrite {
                get { return wrappedStream.CanWrite; }
            }

            public override void Flush() {
                wrappedStream.Flush();
            }

            public override long Length {
                get { return wrappedStream.Length; }
            }

            public override long Position {
                get { return wrappedStream.Position; }
                set { wrappedStream.Position = value; }
            }

            public override int Read(byte[] buffer, int offset, int count) {
                long relativeOffset = wrappedStream.Position - startPosition;
                int result = wrappedStream.Read(buffer, offset, count);
                if (clonedStream.Position != relativeOffset) {
                    clonedStream.Position = relativeOffset;
                }
                clonedStream.Write(buffer, offset, result);
                return result;
            }

            public override long Seek(long offset, SeekOrigin origin) {
                return wrappedStream.Seek(offset, origin);
            }

            public override void SetLength(long value) {
                wrappedStream.SetLength(value);
            }

            public override void Write(byte[] buffer, int offset, int count) {
                long relativeOffset = wrappedStream.Position - startPosition;
                wrappedStream.Write(buffer, offset, count);
                if (clonedStream.Position != relativeOffset) {
                    clonedStream.Position = relativeOffset;
                }
                clonedStream.Write(buffer, offset, count);
            }

            public override void Close() {
                wrappedStream.Close();
                base.Close();
            }

            protected override void Dispose(bool disposing) {
                if (wrappedStream != null) {
                    wrappedStream.Dispose();
                    wrappedStream = null;
                }
                base.Dispose(disposing);
            }
        }
    }
}

You can utilize SoapExtension from existing WSE2.0 framework to intercept the responses from the server.

public class MyClientSOAPExtension : SoapExtension
{

     Stream oldStream;
     Stream newStream;

     // Save the Stream representing the SOAP request or SOAP response into
     // a local memory buffer.
     public override Stream ChainStream( Stream stream )
     {
            oldStream = stream;
            newStream = new MemoryStream();
            return newStream;
     }

    public override void ProcessMessage(SoapMessage message)
    {
       switch (message.Stage)
        {
            case SoapMessageStage.BeforeDeserialize:
                // before the XML deserialized into object.
                break;
            case SoapMessageStage.AfterDeserialize:
                break;        
            case SoapMessageStage.BeforeSerialize:
                break;
            case SoapMessageStage.AfterSerialize:
                break;            
            default:
                throw new Exception("Invalid stage...");
        }       
    }
}

At stage of SoapMessageStage.BeforeDeserialize, You can read the expected data you want from oldstream (e.g. use XmlReader). Then store the expected data somewhere for yourself to use and also you need forward the old stream data to the newstream for web service later stage to use the data, e.g. deserialize XML into objects.

The sample of logging all the traffic for the web service from MSDN

Here is an example you can setup using Visual studio web reference to http://footballpool.dataaccess.eu/data/info.wso?WSDL

Basically, you must insert in the webservice call chain a XmlReader spyer that will reconstruct the raw XML.

I believe this way is somehow simpler that using SoapExtensions.

Solution solution was inspired by http://orbinary.com/blog/2010/01/getting-the-raw-soap-xml-sent-via-soaphttpclientprotocol/

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.IO;
using System.Reflection;
using System.Xml;


namespace ConsoleApplication1 {

    public class XmlReaderSpy : XmlReader {
        XmlReader _me;
        public XmlReaderSpy(XmlReader parent) {
            _me = parent;
        }

        /// <summary>
        /// Extracted XML.
        /// </summary>
        public string Xml;

        #region Abstract method that must be implemented
        public override XmlNodeType NodeType {
            get {

                return _me.NodeType;
            }
        }

        public override string LocalName {
            get {
                return _me.LocalName;
            }
        }

        public override string NamespaceURI {
            get {
                return _me.NamespaceURI;
            }
        }

        public override string Prefix {
            get {
                return _me.Prefix;
            }
        }

        public override bool HasValue {
            get { return _me.HasValue; }
        }

        public override string Value {
            get { return _me.Value; }
        }

        public override int Depth {
            get { return _me.Depth; }
        }

        public override string BaseURI {
            get { return _me.BaseURI; }
        }

        public override bool IsEmptyElement {
            get { return _me.IsEmptyElement; }
        }

        public override int AttributeCount {
            get { return _me.AttributeCount; }
        }

        public override string GetAttribute(int i) {
            return _me.GetAttribute(i);
        }

        public override string GetAttribute(string name) {
            return _me.GetAttribute(name);
        }

        public override string GetAttribute(string name, string namespaceURI) {
            return _me.GetAttribute(name, namespaceURI);
        }

        public override void MoveToAttribute(int i) {
            _me.MoveToAttribute(i);
        }

        public override bool MoveToAttribute(string name) {
            return _me.MoveToAttribute(name);
        }

        public override bool MoveToAttribute(string name, string ns) {
            return _me.MoveToAttribute(name, ns);
        }

        public override bool MoveToFirstAttribute() {
            return _me.MoveToFirstAttribute();
        }

        public override bool MoveToNextAttribute() {
            return _me.MoveToNextAttribute();
        }

        public override bool MoveToElement() {
            return _me.MoveToElement();
        }

        public override bool ReadAttributeValue() {
            return _me.ReadAttributeValue();
        }

        public override bool Read() {
            bool res = _me.Read();

            Xml += StringView();


            return res;
        }

        public override bool EOF {
            get { return _me.EOF; }
        }

        public override void Close() {
            _me.Close();
        }

        public override ReadState ReadState {
            get { return _me.ReadState; }
        }

        public override XmlNameTable NameTable {
            get { return _me.NameTable; }
        }

        public override string LookupNamespace(string prefix) {
            return _me.LookupNamespace(prefix);
        }

        public override void ResolveEntity() {
            _me.ResolveEntity();
        }

        #endregion


        protected string StringView() {
            string result = "";

            if (_me.NodeType == XmlNodeType.Element) {
                result = "<" + _me.Name;

                if (_me.HasAttributes) {
                    _me.MoveToFirstAttribute();
                    do {
                        result += " " + _me.Name + "=\"" + _me.Value + "\"";
                    } while (_me.MoveToNextAttribute());

                    //Let's put cursor back to Element to avoid messing up reader state.
                    _me.MoveToElement();
                }

                if (_me.IsEmptyElement) {
                    result += "/";
                }

                result += ">";
            }

            if (_me.NodeType == XmlNodeType.EndElement) {
                result = "</" + _me.Name + ">";
            }

            if (_me.NodeType == XmlNodeType.Text || _me.NodeType == XmlNodeType.Whitespace) {
                result = _me.Value;
            }



            if (_me.NodeType == XmlNodeType.XmlDeclaration) {
                result = "<?"  + _me.Name + " " +   _me.Value + "?>";
            }

            return result;

        }
    }

    public class MyInfo : ConsoleApplication1.eu.dataaccess.footballpool.Info {             

        protected XmlReaderSpy _xmlReaderSpy;

        public string Xml {
            get {
                if (_xmlReaderSpy != null) {
                    return _xmlReaderSpy.Xml;
                }
                else {
                    return "";
                }
            }
        }


        protected override XmlReader GetReaderForMessage(System.Web.Services.Protocols.SoapClientMessage message, int bufferSize) {          
            XmlReader rdr = base.GetReaderForMessage(message, bufferSize);
            _xmlReaderSpy = new XmlReaderSpy((XmlReader)rdr);
            return _xmlReaderSpy;
        }

    }

    class Program {
        static void Main(string[] args) {

            MyInfo info = new MyInfo();
            string[] rest = info.Cities();

            System.Console.WriteLine("RAW Soap XML response :\n"+info.Xml);
            System.Console.ReadLine();
        }
    }
}

Old thread, but in case others are looking to do this today: these ideas of leveraging SoapExtension or creating 'spy' classes are great, but don't work in .NET Core.

@mting923's suggestion to use IClientMessageInspector approach works in .NET Core 3.1; see here: Get SOAP Message before sending it to the WebService in .NET.

A generated SOAP proxy class is still just a WCF client under the hood, and so the IClientMessageInspector approach works a treat, even for an .NET Core Azure Function calling an older SOAP web service. The following works for me in a .NET Core 3.1 Azure Function:

public class SoapMessageInspector : IClientMessageInspector
{
    public string LastRequestXml { get; private set; }
    public string LastResponseXml { get; private set; }

    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        LastRequestXml = request.ToString();
        return request;
    }

    public void AfterReceiveReply(ref Message reply, object correlationState)
    {
        LastResponseXml = reply.ToString();
    }
}

public class SoapInspectorBehavior : IEndpointBehavior
{
    private readonly SoapMessageInspector inspector_ = new SoapMessageInspector();

    public string LastRequestXml => inspector_.LastRequestXml;
    public string LastResponseXml => inspector_.LastResponseXml;

    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    {
    }

    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
    }

    public void Validate(ServiceEndpoint endpoint)
    {
    }

    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        clientRuntime.ClientMessageInspectors.Add(inspector_);
    }
}

And then it can be set up like this:

    var client = new ServiceClient();
    var soapInspector = new SoapInspectorBehavior();
    client.Endpoint.EndpointBehaviors.Add(soapInspector);

After invoking a web service call on the client proxy, soapInspector.LastRequestXml and soapInspector.LastResponseXml will contain the raw SOAP request and response (as strings).