Try/catch not catching HttpListenerException

Question

I made a simple http endpoint using Grapevine (which is just an interface for HttpListener). Sometimes the connection drops before I SendResponse which leads to a HttpListenerException, but I don't understand why the try/catch doesn't handle the exception and the whole server crashes.

Error:

Application: Movimiento de Placas.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Net.HttpListenerException
Stack:
   at System.Net.HttpResponseStream.Write(Byte[], Int32, Int32)
   at Grapevine.Interfaces.Server.HttpResponse.SendResponse(Byte[])
   at Grapevine.Server.HttpResponseExtensions.SendResponse(Grapevine.Interfaces.Server.IHttpResponse, System.String)
   at Grapevine.Server.Router.Route(System.Object)
   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(System.Object)
   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()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

Code:

[RestRoute(HttpMethod = HttpMethod.POST, PathInfo = "/patente")]
        public IHttpContext ModificarPantalla(IHttpContext context)
        {
            var dict = HttpUtility.ParseQueryString(context.Request.Payload);
            var json = new JavaScriptSerializer().Serialize(
                dict.Keys.Cast<string>()
                    .ToDictionary(k => k, k => dict[k]));
            var contenido = JsonConvert.DeserializeObject<Patente>(json);
            Server.FormRef.CargarPatente(contenido.Plate, contenido.idCamera);
            UltimaFoto.Fecha = DateTime.Now;
            Task.Run(() => Sqlite.InsertarPatente(contenido));
            try
            {
                context.Response.SendResponse(HttpStatusCode.Ok); //exception occurs here
            }
            catch (Exception ex)
            {

            }

            return context;
        }

Answer 1

This is a known issue. There is a PR that's been hanging around for a while now that fixes this, I'm merging it in now, along with an update that will add support for .NET Standard. This should be available by the end of the week.

Update: Grapevine 4.1.2 is available on Nuget.org as of August 9, 2019