Question

I have a big list of proxy servers (txt file , Format = ip:port in each line) and wrote the code below for checking them:

    public static void MyChecker()
    {
        string[] lines = File.ReadAllLines(txtProxyListPath.Text);
        List<string> list_lines = new List<string>(lines);
        List<string> list_lines_RemovedDup = new List<string>();
        HashSet<string> HS = new HashSet<string>();
        int Duplicate_Count = 0;
        int badProxy = 0;
        int CheckedCount = 0;

        foreach (string line in list_lines)
        {
            string[] line_char = line.Split(':');
            string ip = line_char[0];
            string port = line_char[1];
            if (CanPing(ip))
            {
                if (SoketConnect(ip, port))
                {
                    if (CheckProxy(ip, port))
                    {
                        string ipAndport = ip + ":" + port;
                        if (HS.Add(ipAndport))
                        {
                            list_lines_RemovedDup.Add(ipAndport);
                            CheckedCount++;
                        }
                        else
                        {
                            Duplicate_Count++;
                            CheckedCount++;
                        }
                    }
                    else
                    {
                        badProxy++;
                        CheckedCount++;
                    }
                }
                else
                {
                    badProxy++;
                    CheckedCount++;
                }
            }
            else
            {
                badProxy++;
                CheckedCount++;
            }
    }

    public static bool CanPing(string ip)
    {
        Ping ping = new Ping();

        try
        {
            PingReply reply = ping.Send(ip, 2000);
            if (reply == null)
                return false;

            return (reply.Status == IPStatus.Success);
        }
        catch (PingException Ex)
        {
            return false;
        }
    }

    public static bool SoketConnect(string ip, string port)
    {
        var is_success = false;
        try
        {
            var connsock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            connsock.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, 200);
            System.Threading.Thread.Sleep(500);
            var hip = IPAddress.Parse(ip);
            var ipep = new IPEndPoint(hip, int.Parse(port));
            connsock.Connect(ipep);
            if (connsock.Connected)
            {
                is_success = true;
            }
            connsock.Close();
        }
        catch (Exception)
        {
            is_success = false;
        }
        return is_success;
    }

    public static bool CheckProxy(string ip, string port)
    {
        try
        {
            WebClient WC = new WebClient();
            WC.Proxy = new WebProxy(ip, int.Parse(port));
            WC.DownloadString("http://SpecificWebSite.com");
            return true;
        }
        catch (Exception)
        {
            return false;
        }
    }

But I think I should rewrite these codes because they are very slow.
I have bad delays in these lines :
WC.DownloadString("http://SpecificWebSite.com");
and
PingReply reply = ping.Send(ip, 2000);
and this is not good for a big list.
Did I write these codes in the right direction or should i change them(which parts)?
how can i optimze them?

thanks in advance

Answer 1

There are quite a few things you can improve.

• Don’t sleep the thread for half a second.
• Drop the ping check (since the proxy might be behind a firewall and
  not responding to pings but still working)
• Replace DownloadString with a HttpWebRequest getting the HEAD only.
• Set the timeout of your HttpWebRequest to something lower than
  default (no need to wait that long. If a proxy doesn’t respond within
  10-20secs then you probably don’t want to use it).
• Split your big list into smaller ones and process them at the same
  time.

These alone should speed up your process by quite a bit.

As requested, here’s an example of how to use HttpWebRequests

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Proxy = null;   // set proxy here
request.Timeout = 10000; 
request.Method = "HEAD";

using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
    Console.WriteLine(response.StatusCode);
}