Grapevine (5.0.0-rc.10) randomly(?) throwing System.FormatException after processing several requests

[jskladan]

I'm using Grapevine 5.0.0-rc.10 (from a NuGet package) as a REST server base for a project that runs as a windows service (IMO not relevant, but mentioning to be complete), and it randomly dies on this (gotten to the error through the windows' logs):

Application: EwayEasyIV.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.FormatException
   at System.Number.StringToNumber(System.String, System.Globalization.NumberStyles, NumberBuffer ByRef, System.Globalization.NumberFormatInfo, Boolean)
   at System.Number.ParseDecimal(System.String, System.Globalization.NumberStyles, System.Globalization.NumberFormatInfo)
   at System.Convert.ToDecimal(System.String)
   at Grapevine.QualityValues.GroupByQualityFactor(System.String)
   at Grapevine.QualityValues.Parse(System.String)
   at Grapevine.HttpContext..ctor(System.Net.HttpListenerContext, System.Threading.CancellationToken)
   at Grapevine.RestServerBase+<>c.<.ctor>b__55_0(System.Object, System.Threading.CancellationToken)
   at Grapevine.RestServer+<RequestHandlerAsync>d__39.MoveNext()
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()

This is the server's code:

using Grapevine;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using NLog;
using System;
using System.Configuration;
using System.IO;
using System.Text;
using System.Threading.Tasks;

namespace EwayEasyIV
{
    internal class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddLogging(logging => logging.ClearProviders());
        }

        public void ConfigureServer(IRestServer server)
        {
            server.Prefixes.Clear();
            server.Prefixes.Add(
                string.Format(
                    "http://{0}:{1}/",
                    ConfigurationManager.AppSettings["RestServerHost"],
                    ConfigurationManager.AppSettings["RestServerPort"]
                    )
                );
        }
    }

    internal class HttpServer
    {
        private IRestServer _server;
        private static Logger _log;

        public HttpServer(Logger log = null)
        {
            _server = RestServerBuilder.From<Startup>().Build();
            if (log == null)
            {
                log = LogManager.GetCurrentClassLogger();
            }
            _log = log;

            _server.AfterStarting += (s) =>
            {
                var sb = new StringBuilder(Environment.NewLine);
                sb.Append($"********************************************************************************{Environment.NewLine}");
                sb.Append($"* Server listening on {string.Join(", ", _server.Prefixes)}{Environment.NewLine}");
                sb.Append($"********************************************************************************{Environment.NewLine}");

                _log.Info(sb);
                Console.Write(sb);
            };
        }

        public void Run()
        {
            _server.Start();
        }

        public void Stop()
        {
            _server.Stop();
        }

        [RestResource(BasePath = "api")]
        public class ApiResource
        {
            [RestRoute("Post", "/easy_digisign_payload_hook")]
            [Header("Content-Type", "application/json")]
            public async Task EasyDigisignPayloadHook(IHttpContext context)
            {
                string documentContents;
                Logger log = LogManager.GetLogger("EasyDigisignPayloadHook");

                using (Stream receiveStream = context.Request.InputStream)
                {
                    using (StreamReader readStream = new StreamReader(receiveStream, Encoding.UTF8))
                    {
                        try
                        {
                            documentContents = readStream.ReadToEnd();
                        }
                        catch (Exception e)
                        {
                            log.Error(e.Message);
                            log.Error(e.ToString());
                            await context.Response.SendResponseAsync(HttpStatusCode.BadRequest).ConfigureAwait(false);
                            return;
                        }
                    }
                }

                log.Debug(documentContents);
                await context.Response.SendResponseAsync(HttpStatusCode.Ok).ConfigureAwait(false);
            }
        }
    }
}

The Server handles (to my knowledge) a random amount of requests, and then the app dies on the aforementioned error.

Thank you for any and all help, I'm fairly new to C# (many years of Linux/Python development under my belt though), so I might be missing something obvious.

[scottoffen]

When the server fails, what is the value of the Accept-Encoding header on the request?