RestTest - sample console app for receiving HTTP Posts and logging said posts. Posting to http://localhost.fiddler:9000/api/test will allow you to see the request in fiddler

Log4NetAppenderFactory.cs

using System.IO;
using log4net.Appender;
using log4net.Core;
using log4net.Layout;

namespace RestTest.Logging
{
    public static class Log4NetAppenderFactory
    {
        private static readonly PatternLayout PatternLayout = new PatternLayout("[%-5level][%date][%thread][%logger]: %message%newline");
        
        private const long TenMb = (10 * 1024 * 1024);

        /// <summary>
        /// Creates a size based rolling file appender that is configured to fill up 31 x 10Mb log files before deleting old logs.
        /// Each time the log file roll overs it appends an incrementing counter onto the end of the filename.
        /// </summary>
        /// <param name="processName"></param>
        /// <param name="loggingPath"></param>
        /// <param name="desiredLoggingLevel">Log threshold level to use, defaults to ALL if not supplied.</param>
        /// <returns></returns>
        public static RollingFileAppender CreateRollingFileAppender(string processName, string loggingPath, Level desiredLoggingLevel = null)
        {
            var levelToUse = desiredLoggingLevel ?? Level.All;
            var fileAppender = new RollingFileAppender
            {
                File = Path.Combine(loggingPath, processName + ".log"),
                AppendToFile = true,
                ImmediateFlush = true,
                Layout = PatternLayout,
                LockingModel = new FileAppender.MinimalLock(),
                Threshold = levelToUse,
                // use size base options so log4net will auto remove old logs
                RollingStyle = RollingFileAppender.RollingMode.Size,
                MaxSizeRollBackups = 30, // gives us 31 files - the original plus 30 backups.  multiply that by 10Mb then we need 310Mb of storage
                MaxFileSize = TenMb,
                StaticLogFileName = false,
                PreserveLogFileNameExtension = false,
                CountDirection = 1
            };
            fileAppender.ActivateOptions();
            return fileAppender;
        }

        public static ColoredConsoleAppender CreateColoredConsoleAppender(Level desiredLoggingLevel = null)
        {
            var levelToUse = desiredLoggingLevel ?? Level.All;
            var fileAppender = new ColoredConsoleAppender
            {
                Layout = new PatternLayout("%message%newline"),
                Threshold = levelToUse
            };
            fileAppender.ActivateOptions();
            return fileAppender;
        }
    }
}

Log4NetSetUp.cs

using System.Reflection;
using log4net;
using log4net.Appender;
using log4net.Core;
using log4net.Repository.Hierarchy;

namespace RestTest.Logging
{
    public static class Log4NetSetUp
    {
        private static readonly ILog Log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
        public const string LoggingPath = "C:\\Temp\\Logs";
        public static void InitialiseLog4Net()
        {
            var logAppenders = new IAppender[]
            {
                Log4NetAppenderFactory.CreateColoredConsoleAppender(Level.All),
                Log4NetAppenderFactory.CreateRollingFileAppender("RestTest", LoggingPath, Level.All)
            };
            var hierarchy = (Hierarchy)LogManager.GetRepository();
            hierarchy.Clear();
            foreach (var appender in logAppenders)
            {
                hierarchy.Root.AddAppender(appender);
            }
            hierarchy.Root.Level = Level.Debug;
            hierarchy.Configured = true;
            Log.Info("Log4Net configuration complete!");
        }
    }
}

packages.config

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="log4net" version="2.0.3" targetFramework="net45" />
  <package id="Microsoft.AspNet.WebApi.Client" version="5.2.2" targetFramework="net45" />
  <package id="Microsoft.AspNet.WebApi.Core" version="5.2.2" targetFramework="net45" />
  <package id="Microsoft.AspNet.WebApi.Owin" version="5.2.2" targetFramework="net45" />
  <package id="Microsoft.AspNet.WebApi.OwinSelfHost" version="5.2.2" targetFramework="net45" />
  <package id="Microsoft.Owin" version="2.0.2" targetFramework="net45" />
  <package id="Microsoft.Owin.Host.HttpListener" version="2.0.2" targetFramework="net45" />
  <package id="Microsoft.Owin.Hosting" version="2.0.2" targetFramework="net45" />
  <package id="Newtonsoft.Json" version="6.0.4" targetFramework="net45" />
  <package id="Owin" version="1.0" targetFramework="net45" />
</packages>

Program.cs

using System;
using Microsoft.Owin.Hosting;
using RestTest.Logging;

namespace RestTest
{
    class Program
    {
        static void Main()
        {
            const string baseAddress = "http://localhost:9000/";
            Log4NetSetUp.InitialiseLog4Net();
            using (WebApp.Start<Startup>(baseAddress))
            {
                Console.WriteLine("Running as " + baseAddress);
                Console.WriteLine("Logging to " + Log4NetSetUp.LoggingPath);
                Console.WriteLine("Send a POST request to {0}api/Test to get statrted", baseAddress);
                Console.WriteLine("Press enter to close");
                Console.ReadLine();
            }
        }
    }
}

Startup.cs

using System.Web.Http;
using Owin;

namespace RestTest
{
    public class Startup
    {
        public void Configuration(IAppBuilder appBuilder)
        {
            var config = new HttpConfiguration();
            config.Routes.MapHttpRoute("DefaultApi","api/{controller}/{id}",new { id = RouteParameter.Optional });
            appBuilder.UseWebApi(config);
        }
    }
}

TestController.cs

using System.Linq;
using System.Net;
using System.Net.Http;
using System.Reflection;
using System.Web.Http;
using log4net;

namespace RestTest
{
    public class TestController : ApiController
    {
        private static readonly ILog Log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        public HttpResponseMessage Post()
        {
            var route = Request.GetRouteData().Route.RouteTemplate;
            var method = Request.Method.Method;
            var url = Request.RequestUri.AbsoluteUri;

            Log.InfoFormat("{0} {1}, route: {2}, controller:{3}, action:{4}", method, url, route, GetType().Name, MethodBase.GetCurrentMethod().Name);
            Log.InfoFormat(string.Join("|", Request.Headers.Select(kvp => string.Format("Key:{0}, Value:{1}", kvp.Key, kvp.Value))));
            Log.Info(Request.Content.ReadAsStringAsync().Result);
            return new HttpResponseMessage(HttpStatusCode.OK);
        }
    }
}