public Task <HttpResponseMessage> ExecuteAuthorizationFilterAsync(HttpActionContext actionContext, CancellationToken cancellationToken, Func <Task <HttpResponseMessage> > continuation) { IEnumerable <string> headers; if (actionContext.Request.Headers.TryGetValues("accessToken", out headers)) { var accessToken = headers.First(); var user = userDataBase.Get(accessToken); if (user != null) { return(continuation()); } else { return(CreateTask(actionContext)); } } else { return(CreateTask(actionContext)); } }