Fix of JsonMediaTypeFormatter (ASP.net WebAPI) that does not convert JSON to object when Request is in Chunked Transfer Encoding.

XJsonMediaTypeFormatter.cs

    /// <summary>
    /// Fix of JsonMediaTypeFormatter that does not convert JSON to object when Request is in Chunked Transfer Encoding.
    /// </summary>
    public class XJsonMediaTypeFormatter : JsonMediaTypeFormatter
    {
        /// <summary>
        /// Replaces web api default JsonMediaTypeFormatter with this instance.
        /// Usage:
        ///     protected void Application_Start()
        ///     {
        ///         ...
        ///         XJsonMediaTypeFormatter.FixConfiguration(GlobalConfiguration.Configuration);
        ///         ...
        /// </summary>
        /// <param name="configuration"></param>
        public static void FixConfiguration(HttpConfiguration configuration)
        {
            var formatter = new XJsonMediaTypeFormatter
                            {
                                SerializerSettings =
                                {
                                    NullValueHandling = NullValueHandling.Ignore
                                }
                            };

            configuration.Formatters.Remove(configuration.Formatters.JsonFormatter);
            configuration.Formatters.Add(formatter);

        }

        // From BaseJsonMediaTypeFormatter in Microsoft.AspNet.WebApi.Client.5.1.2\lib\net45\System.Net.Http.Formatting.dll
        public override Task<object> ReadFromStreamAsync(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger)
        {
            if (content.Headers.ContentLength.HasValue && content.Headers.ContentLength == 0)
                // "Messages MUST NOT include both a Content-Length header field and a non-identity transfer-coding. 
                //  If the message does include a non-identity transfer-coding, the Content-Length MUST be ignored."
                // (RFC 2616, Section 4.4)
                // http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html
                // Fix for that the base-implementation defaults to 'default' value if Content-Length is 0.
                content.Headers.ContentLength = new long?();
            return base.ReadFromStreamAsync(type, readStream, content, formatterLogger);
        }
    }

    /*
     * "Long" version
     *
    /// <summary>
    /// Fix of JsonMediaTypeFormatter that does not convert JSON to object when Request is in Chunked Transfer Encoding.
    /// </summary>
    public class XJsonMediaTypeFormatter : JsonMediaTypeFormatter
    {
        /// <summary>
        /// Replaces web api default JsonMediaTypeFormatter with this instance.
        /// Usage:
        ///     protected void Application_Start()
        ///     {
        ///         ...
        ///         XJsonMediaTypeFormatter.FixConfiguration(GlobalConfiguration.Configuration);
        ///         ...
        /// </summary>
        /// <param name="configuration"></param>
        public static void FixConfiguration(HttpConfiguration configuration)
        {
            var formatter = new XJsonMediaTypeFormatter
                            {
                                SerializerSettings =
                                {
                                    NullValueHandling = NullValueHandling.Ignore
                                }
                            };

            configuration.Formatters.Remove(configuration.Formatters.JsonFormatter);
            configuration.Formatters.Add(formatter);

        }

        // From BaseJsonMediaTypeFormatter in Microsoft.AspNet.WebApi.Client.5.1.2\lib\net45\System.Net.Http.Formatting.dll
        public override Task<object> ReadFromStreamAsync(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger)
        {
            try
            {
                return Task.FromResult(ReadFromStream(type, readStream, content, formatterLogger));
            }
            catch (Exception ex)
            {
                //return TaskHelpers.FromError<object>(ex);
                return FromError<object>(ex);
            }
        }

        // From System.Threading.Tasks.TaskHelpers in Microsoft.AspNet.WebApi.Client.5.1.2\lib\net45\System.Net.Http.Formatting.dll
        private static Task<TResult> FromError<TResult>(Exception exception)
        {
            TaskCompletionSource<TResult> completionSource = new TaskCompletionSource<TResult>();
            completionSource.SetException(exception);
            return completionSource.Task;
        }


        // From BaseJsonMediaTypeFormatter in Microsoft.AspNet.WebApi.Client.5.1.2\lib\net45\System.Net.Http.Formatting.dll
        private object ReadFromStream(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger)
        {
            var contentHeaders = content == null ? null : content.Headers;
            var effectiveEncoding = SelectCharacterEncoding(contentHeaders);
            try
            {
                var res = ReadFromStream(type, readStream, effectiveEncoding, formatterLogger);
                return res;
            }
            catch (Exception ex)
            {
                if (formatterLogger == null)
                    throw;

                formatterLogger.LogError(string.Empty, ex);
                return GetDefaultValueForType(type);
            }
        }

        /*
         * BaseJsonMediaTypeFormatter.ReadFromStream implementation here only for reference
         * 
        private object ReadFromStream(Type type, Stream readStream, HttpContent content, IFormatterLogger formatterLogger)
        {
            HttpContentHeaders contentHeaders = content == null ? (HttpContentHeaders)null : content.Headers;
            if (contentHeaders != null)
            {
                long? contentLength = contentHeaders.ContentLength;
                if ((contentLength.GetValueOrDefault() != 0L ? 0 : (contentLength.HasValue ? 1 : 0)) != 0)
                    return MediaTypeFormatter.GetDefaultValueForType(type);
            }
            Encoding effectiveEncoding = this.SelectCharacterEncoding(contentHeaders);
            try
            {
                return this.ReadFromStream(type, readStream, effectiveEncoding, formatterLogger);
            }
            catch (Exception ex)
            {
                if (formatterLogger == null)
                {
                    throw;
                }
                else
                {
                    formatterLogger.LogError(string.Empty, ex);
                    return MediaTypeFormatter.GetDefaultValueForType(type);
                }
            }
        }
         */
    }
    */

This saved me!! Thanks for sharing this! Two days hunting down the issue, and it turned out to be this problem.