webapi call fails only when recycling application pool using unity DI

Question

I am calling a web api service that only fails the first time I recycle the application pool. After that all calls work fine.

The process is like this..

Call Service --> return OK

Go to iis and recycle app pool ( I wait 10 secs)

Call Service --> An internal server error occurred. Please try again later.

Call Service --> return OK

... Go to iis and recycle app pool ( I wait 10 secs) Call Service --> An internal server error occurred. Please try again later.

Call Service --> return OK

...

The client is a console application framework 4.0 using this method:

        public static object Send(string webAddr, object param)
        {
            HttpUtil.IgnoreBadCertificates();

            HttpWebRequest request = null;
            object result = null;

            request = (HttpWebRequest)WebRequest.Create(webAddr);
            request.ContentType = "application/json; charset=utf-8";
            request.Method = "POST";
            request.Accept = "application/json";

            String u = GetString(a1);
            String p = GetString(a1) + GetString(a2);

            String encoded = System.Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(u + ":" + p));
            request.Headers.Add("Authorization", "Basic " + encoded);

            using (var streamWriter = new StreamWriter(request.GetRequestStream()))
            {
                var myJsonString = Newtonsoft.Json.JsonConvert.SerializeObject(param);
                streamWriter.Write(myJsonString);
                streamWriter.Flush();
            }

            var response = (HttpWebResponse)request.GetResponse();

            using (var streamReader = new StreamReader(response.GetResponseStream()))
            {
                result = streamReader.ReadToEnd();
            }

            return result;
        }

And the webapi is framework 4.5:

 public class CambiosController : BaseApiController
    {
        private ICambioService cambioService;

        public CambiosController(ICambioService cambioService)
        {
            this.cambioService = cambioService;
        }

        [HttpPost]
        [Authorize]
        public HttpResponseMessage Post([FromBody] CambioRequest cambioRequest)
        {
            HttpResponseMessage response = null;

            if (cambioRequest == null)
            {
                Exception ex = new ArgumentException("cambioRequest");
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ex);
            }

            try
            {
                var result = this.cambioService.EnviarConfiguracion(cambioRequest);
                response = Request.CreateResponse(HttpStatusCode.OK, result);
            }
            catch (Exception ex)
            {
                response = Request.CreateErrorResponse(HttpStatusCode.InternalServerError, ex);
            }

            return response;
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                this.cambioService.Dispose();
            }

            base.Dispose(disposing);
        }

Unity config:

public static void RegisterComponents()
{
    LoggerFacility.Debug(string.Empty, string.Empty, "UnityConfig.RegisterComponents()");

    var container = new UnityContainer();

    container.RegisterTypes(
        AllClasses.FromAssemblies(BuildManager.GetReferencedAssemblies().Cast<Assembly>())
        .Where(x => x.Name != "IUnitOfWork" && x.Name != "IDbContext"),
        WithMappings.FromMatchingInterface, WithName.Default, overwriteExistingMappings: true);

    container.RegisterType<IUnitOfWork, UnitOfWork>(new PerResolveLifetimeManager());
    container.RegisterType<IDbContext, ControlConfigContext>(new PerResolveLifetimeManager());

    GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
}

WebApi application pool is framework 4 integrated mode, running as Network Service. ProcessModel Idle Timeout (minutes 0) The only configuration changed from default. IIS 7.5

Hi, I did a similar case for test it, but for me all is ok. Can you add a global error handler to log more information about the error? asp.net/web-api/overview/error-handling/… — Julito Avellaneda
Grrr. Your title totally asks the same question I have, but your answer is nothing like my problem. :-) — Neil

nerlijma nerlijma · Accepted Answer · 2015-08-17T02:40:36

The problem was related to a reverse proxy we had. It was set to wait only 15 seconds for the url I was using. Therefore, when recycling the app pool (as it has to load all unity stuff) it took 16 seconds most of the time. The thing to notice is that a reverse proxy error will throw a Internal Server Error from ASP.NET webapi, noting related to Timeout or something to give some clue. Good to know now...

webapi call fails only when recycling application pool using unity DI

1 Answers