多线程服务器

Question

I've implemented a server, and am now attempting to make it multi threaded however have come across a problem in that the server fails when data is received and that the StreamWriter cannot read the data from the Stream .

The code is as follows:

class whereisServer
{
    static Socket connection;
    static object threadLock = new object();

    static void Main(string[] args)
    {
        Thread t = new Thread(new ThreadStart(Run));
        t.Start();
    }

    static void Run()
    {
        NetworkStream socketStream;
        TcpListener listener;
        const int PORT = 43;
        try
        {
            listener = new TcpListener(IPAddress.Any, PORT);
            listener.Start();
            while (true)
            {
                connection = listener.AcceptSocket();
                socketStream = new NetworkStream(connection);
                try
                {
                    connection.ReceiveTimeout = 1000;
                    connection.SendTimeout = 1000;
                    Thread t = new Thread(new ParameterizedThreadStart(DoRequest));
                    t.Start(socketStream);
                    //DoRequest(socketStream);
                }
                catch (IOException e)
                {
                    Console.WriteLine(e.Message + "\nTimeOut Handled");
                }
                finally
                {
                    socketStream.Close();
                    connection.Close();
                }
            }
        }
        catch (SocketException e)
        {
            Console.WriteLine(e.Message);
        }
    }

    static void DoRequest(object stream)
    {
        NetworkStream socketStream = (NetworkStream)stream;
        StreamWriter writer = new StreamWriter(socketStream);
        StreamReader reader = new StreamReader(socketStream);

        lock (threadLock)
        {
             //DO SERVER STUFF HERE
        }

When calling the DoRequest method without threads the program runs fine, however when commenting that out and calling the threaded version this is when the problems occur.

I would be grateful if someone could suggest as to why the Stream is unable to function.

Answer 1

In multithreaded case you call the Close methods sooner than DoRequest does its work.

It is because these two lines are in finally block.

socketStream.Close();
connection.Close();

These two lines are executed immediately after the Start method starts the new thread, but before that thread completes its work in DoRequest .

I would recommend you to call these methods inside DoRequest . You can pass connection object into DoRequest , then create socketStream internally in DoRequest and when you are finished, close both these objects before finishing the DoRequest method. (Or you can use any other solution, this is just one option.)