I need to implement raw xml logging before the our wcf service process the incoming request from the clinet how to implement it give the approach

Thanks for sharing the code. Your custom MessageEncoder approach can work, but it is still inside the WCF channel stack. If your requirement is to log the request before WCF parses it and reject invalid XML early, then an HTTP module is a better fit for IIS-hosted WCF over HTTP/S.

HTTP modules run during the ASP.NET request pipeline, for example at BeginRequest, before the request reaches the handler.

Example approach:

using System;
using System.IO;
using System.Text;
using System.Web;
using System.Xml;

public class RawSoapHttpModule : IHttpModule
{
    private static readonly object Sync = new object();

    public void Init(HttpApplication app)
    {
        app.BeginRequest += OnBeginRequest;
    }

    public void Dispose() { }

    private void OnBeginRequest(object sender, EventArgs e)
    {
        var app = (HttpApplication)sender;
        var context = app.Context;
        var request = context.Request;

        if (!request.ContentType.Contains("text/xml") &&
            !request.ContentType.Contains("application/soap+xml"))
        {
            return;
        }

        var stream = request.InputStream;

        if (!stream.CanSeek)
        {
            return;
        }

        stream.Position = 0;

        byte[] body;
        using (var ms = new MemoryStream())
        {
            stream.CopyTo(ms);
            body = ms.ToArray();
        }

        string rawXml = request.ContentEncoding.GetString(body);

        File.AppendAllText(
            context.Server.MapPath("~/App_Data/raw-soap.log"),
            DateTime.UtcNow.ToString("O") + Environment.NewLine + rawXml + Environment.NewLine,
            Encoding.UTF8);

        if (!IsValidXml(body))
        {
            context.Response.StatusCode = 400;
            context.Response.ContentType = "text/plain";
            context.Response.Write("Invalid XML request.");
            context.ApplicationInstance.CompleteRequest();
            return;
        }

        // Important: reset stream so WCF can read it
        stream.Position = 0;
    }

    private static bool IsValidXml(byte[] body)
    {
        try
        {
            var settings = new XmlReaderSettings
            {
                DtdProcessing = DtdProcessing.Prohibit,
                XmlResolver = null
            };

            using (var ms = new MemoryStream(body))
            using (var reader = XmlReader.Create(ms, settings))
            {
                while (reader.Read()) { }
            }

            return true;
        }
        catch (XmlException)
        {
            return false;
        }
    }
}

Register it in web.config:

<system.webServer>
  <modules>
    <add name="RawSoapHttpModule"
         type="YourNamespace.RawSoapHttpModule, YourAssemblyName" />
  </modules>
</system.webServer>

So in short:

• Use HTTP module if the service is IIS-hosted and you need to catch invalid XML before WCF handles it.
• Use your custom encoder if you specifically need WCF channel-level control, but it is not truly “before WCF pipeline”.
• Make sure the log folder has write permission and avoid logging sensitive data in production.

@Danny Nguyen (WICLOUD CORPORATION) This is m,y complete requirement so could you provide a solution for this pls will help @Senthil kumar

Implement an ASP.NET `IHttpModule`.
 Capture the raw request body at `BeginRequest`.
 Do not parse the XML during capture.
 Support malformed XML.
 Do not modify, normalize, pretty-print, re-encode, or rewrite the request body.
 Reset the request stream so WCF can process the same original request.

@Dinesh Sadhasivam already i copied some code for you. please check and update.

Ok thanks I will check that .

Will it be able to handle invalid XML's if sent . how t try it by using http module to handle invalid xml if so let me know that alone here. Thank you @Senthil kumar

its a SOAP xml right.

try this below code and confirm.

public class RawSoapHttpModule : IHttpModule
{
    public void Init(HttpApplication context)
    {
        context.BeginRequest += OnBeginRequest;
    }
    private void OnBeginRequest(object sender, EventArgs e)
    {
        HttpApplication app = (HttpApplication)sender;
        HttpContext ctx = app.Context;
        if (!ctx.Request.ContentType.Contains("xml") &&
            !ctx.Request.ContentType.Contains("soap"))
            return;
        ctx.Request.InputStream.Position = 0;
        string rawXml;
        using (var reader = new StreamReader(ctx.Request.InputStream, Encoding.UTF8, true, 1024, true))
        {
            rawXml = reader.ReadToEnd();
        }
        // Log raw XML
        File.AppendAllText(@"C:\Logs\raw_soap.log", rawXml + Environment.NewLine);
        // Validate XML
        if (!IsValidXml(rawXml))
        {
            Reject(ctx);
            return;
        }
        // Restore stream for WCF
        byte[] buffer = Encoding.UTF8.GetBytes(rawXml);
        ctx.Request.InputStream.Position = 0;
        ctx.Request.InputStream.Write(buffer, 0, buffer.Length);
        ctx.Request.InputStream.Position = 0;
    }
    public void Dispose() { }
    private bool IsValidXml(string xml)
    {
        try { XDocument.Parse(xml); return true; }
        catch { return false; }
    }
    private void Reject(HttpContext ctx)
    {
        ctx.Response.StatusCode = 400;
        ctx.Response.Write("Invalid SOAP XML");
        ctx.Response.End();
    }
}

below lines for web.config

<system.webServer>
  <modules>
    <add name="RawSoapHttpModule" type="YourNamespace.RawSoapHttpModule"/>
  </modules>
</system.webServer>

Thanks.

It is SOAP XML and I need to log the raw xml before even it comes into the wcf pipeline and (what will happen if xml is invalid so for that HTTP module i need to try but dont know how to do that so if you provide a complete implementation for that will helps @Senthil kumar

ok i will provide