using System;
using System.IO;
using System.Net;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace HttpRequestExceptions
{
    class Program
    {
        private Timer connectionTimer; // Normaly we use DispatcherTimer
        private int connectionTimerInterval = 1000; // ms

        // Normally there would be valid url (something like this
        // http://192.168.1.2/goform/ReadWrite), but right now we will simulate
        // request timeout with malformed url.
        const string url = "malformedURL";

        // Connection query just for completeness.
        // Right now it does not affect exceptions.
        readonly string connectedQuery = "redirect=/response.asp&variable=controlxp.axes.Running&value=none&read=1";

        public Program()
        {
            connectionTimer = new Timer(_ => ConnectionTimer_Tick(), null, 0, connectionTimerInterval);
        }

        private async void ConnectionTimer_Tick()
        {
            connectionTimer.Change(Timeout.Infinite, Timeout.Infinite);
            await CheckConnection();
            connectionTimer.Change(connectionTimerInterval, connectionTimerInterval);
        }

        private async Task CheckConnection()
        {
            try
            {
                // Right now we don't care about content of response.
                // We only care if we got something.
                string response = await SendRequestAsync(connectedQuery);
            }
            catch (Exception ex) // For now we will catch everything.
            {
                // Normaly this code is used in WPF application.
                System.Console.WriteLine("Set controls enabled to false");
            }
        }

        // Asynchronously sends HttpRequest with given data.
        // Here Exceptions are thrown. Basically any exception from this
        // method we don't care about and don't want to see in output window.
        private async Task<string> SendRequestAsync(string postData)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            byte[] data = Encoding.ASCII.GetBytes(postData);

            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = data.Length;

            using (Stream stream = await request.GetRequestStreamAsync())
            {
                await stream.WriteAsync(data, 0, data.Length);
            }

            string responseString;

            using (WebResponse response = await request.GetResponseAsync())
            using (StreamReader reader = new StreamReader(response.GetResponseStream()))
            {
                responseString = await reader.ReadToEndAsync();
            }

            return responseString;
        }

        static void Main(string[] args)
        {
            Program p = new Program();

            System.Console.ReadLine();
        }
    }
}