How do I get access to SOAP response

Question

(If anything here needs clarification/ more detail please let me know.)

I have an application (C#, 2.* framework) that interfaces with a third-party webservice using SOAP. I used thinktecture's WSCF add-in against a supplied WSDL to create the client-side implementation. For reasons beyond my control the SOAP message exchange uses WSE2.0 for security (the thinctecture implementation had to be modified to include the WSE2.0 reference). In addition to the 'normal' data package I attach a stored X509 cert and a binary security token from a previous call to a different web service. We are using SSL encryption of some sort - I don't know the details.

All the necessary serialization/deserialization is contained in the web service client - meaning when control is returned to me after calling the client the entire XML string contained in the SOAP response is not available to me - just the deserialized components. Don't get me wrong - I think that's good because it means I don't have to do it myself.

However, in order for me to have something worth storing/archiving I am having to re-serialize the data at the root element. This seems like a waste of resources since my result was in the SOAP response.

Now for my question: How can I get access to a 'clear' version of the SOAP response so that I don't have to re-serialize everything for storage/archiving?

Edit- My application is a 'formless' windows app running as a network service - triggered by a WebsphereMQ client trigger monitor. I don't think ASP.NET solutions will apply.

Edit - Since the consensus so far is that it doesn't matter whether my app is ASP.NET or not then I will give CodeMelt's (and by extension Chris's) solution a shot.

Answer 1

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

Answer 2

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();
        }
    }
}

Answer 3

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);
            }
        }
    }
}

Answer 4

The MSDN Library includes example code for obtaining the XML of both the request and the response that you can use to archive it. Obviously you'll have to make some changes since the example stores data in a text file, but it isn't too complicated.