"How are you?" で始まる UDP 非同期通信。

AsyncUDPGuestSample.cs

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;


namespace demo.asyncudp.guest {


    /// <summary>
    ///
    /// </summary>
    class AsyncUDPGuestSample {
        /// <summary>
        /// 
        /// </summary>
        /// <param name="ar"></param>
        public void sendCompleted(IAsyncResult ar) {
            messageSent = true;
        }



        /// <summary>
        /// 
        /// </summary>
        /// <param name="ar"></param>
        public void receiveCompleted(IAsyncResult ar) {
            messageReceived = true;
        }


        /// <summary>
        /// 
        /// </summary>
        /// <param name="args"></param>
        public void run(string[] args) {
            int listen_port = 2000;
            //IPHostEntry host = Dns.GetHostEntry( Dns.GetHostName() );
            //Stack<IPAddress> address_stack = new Stack<IPAddress>( host.AddressList );
            //IPEndPoint remote_point = new IPEndPoint( address_stack.Pop(), listen_port );
            // 受信から始めるときは、IP アドレスに Any(0.0.0.0) を入れておきます。
            IPEndPoint listen_point = new IPEndPoint( IPAddress.Any, listen_port );

            UdpClient client = new UdpClient( listen_point );
            Encoding encoding = Encoding.UTF8;
            string greeting = string.Empty;
            string segment = string.Empty;
            byte[] send_bytes = null;
            int times = 0;

            while ( true ) {
                /*
                 * Guest は bob。
                 */
                Console.Write( "alice > " );
                IAsyncResult done = client.BeginReceive( receiveCompleted, null );

                while ( !messageReceived ) {
                    Thread.Sleep( 100 );
                }
                //segment = encoding.GetString( client.EndReceive( done, ref listen_point ) );
                // listen_point には受信した IP アドレスとポート番号が入ります。
                segment = encoding.GetString( client.EndReceive( done, ref listen_point ) );
                Console.WriteLine( segment );

                if ( segment.StartsWith( "bye" ) )
                    break;

                Thread.Sleep( 1000 );

                if ( segment.EndsWith( "How are you?" ) ) {
                    Random r = new Random();
                    int index = r.Next( CONDITIONS.Length );

                    greeting = string.Format( "{0} Thanks. How are you?", CONDITIONS[index] );
                } else {
                    greeting = "over.";
                }

                Console.WriteLine( "bob < {0}", greeting );
                send_bytes = encoding.GetBytes( greeting );
                // 次に送信するときは、前に受信した IPEndPoint オブジェクトを指定します。
                done = client.BeginSend( send_bytes, send_bytes.Length, listen_point, sendCompleted, null );

                while ( !messageSent ) {
                    if ( times > 100 ) {
                        if ( !done.IsCompleted )
                            Console.WriteLine( "タイムアウトしました。" );
                        /* 
                         * タイムアウトしたら、greeting を "bye." にして待機ループを終了します。
                         */
                        greeting = "bye.";
                        break;
                    }
                    Thread.Sleep( 100 );

                    ++times;
                }
                client.EndSend( done );
                times = 0;
                messageSent = false;
            }
        }


        /// <summary>
        /// 
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args) {
            AsyncUDPGuestSample progn = new AsyncUDPGuestSample();

            progn.run( args );
        }


        /// <summary>
        /// 
        /// </summary>
        private static bool messageSent = false;
        /// <summary>
        /// 
        /// </summary>
        private static bool messageReceived = false;
        /// <summary>
        /// 
        /// </summary>
        static string[] CONDITIONS = new string[] { "Not bad.", "Good!", "Pretty Good!", "Great!" };
    }


}

AsyncUDPHostSample.cs

using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;


namespace demo.asyncudp.client {


    /// <summary>
    /// 
    /// </summary>
    class AsyncUDPHostSample {


        /// <summary>
        /// 
        /// </summary>
        public AsyncUDPHostSample() {
            IPHostEntry host = Dns.GetHostEntry( Dns.GetHostName() );
            Stack<IPAddress> address_stack = new Stack<IPAddress>( host.AddressList );
            this.remote_point_ = new IPEndPoint( address_stack.Pop(), 2000 );
        }


        /// <summary>
        /// 
        /// </summary>
        /// <param name="ar"></param>
        public void sendCompleted(IAsyncResult ar) {
            UdpClient client = (UdpClient)ar.AsyncState;
            //Console.WriteLine( "    number of bytes sent: {0}", client.EndSend( ar ) );

            messageSent = true;
        }


        /// <summary>
        /// 
        /// </summary>
        public void receiveCompleted(IAsyncResult ar) {
            messageReceived = true;
        }


        /// <summary>
        /// 
        /// </summary>
        void run(string[] args) {
            int times = 0;
            UdpClient client = new UdpClient();
            string greeting = "Hi, How are you?";
            string segment = string.Empty;
            Encoding encoding = Encoding.UTF8;
            byte[] send_bytes = null;
            IAsyncResult done = null;

            client.Connect( remote_point_ );

            while ( true ) {
                Console.WriteLine( "alice < {0}", greeting );
                send_bytes = encoding.GetBytes( greeting );
                done = client.BeginSend( send_bytes, send_bytes.Length, sendCompleted, client );

                while ( !messageSent ) {
                    if ( times > 300 ) {
                        if ( !done.IsCompleted )
                            Console.WriteLine( "タイムアウトしました。" );
                        /*
                         * タイムアウトしたら、greeting を "bye." にして待機ループを終了します。
                         */
                        greeting = BYE;
                        break;
                    }
                    Thread.Sleep( 100 );

                    ++times;
                }
                times = 0;
                messageSent = false;

                //if ( !done.CompletedSynchronously )
                //    greeting = BYE;

                if ( greeting.StartsWith( "bye" ) )
                    break;

                Thread.Sleep( 1000 );
                
                done = client.BeginReceive( receiveCompleted, null );
                Console.Write( "bob > " );
                while ( !messageReceived ) {
                    Thread.Sleep( 100 );
                }
                segment = encoding.GetString( client.EndReceive( done, ref remote_point_ ) );
                Console.WriteLine( segment );

                if ( segment.EndsWith( "How are you?" ) ) {
                    Random r = new Random();

                    greeting = CONDITIONS[r.Next( CONDITIONS.Length )];
                } else if ( segment.StartsWith( "over" ) ) {
                    greeting = BYE;
                } else {
                    greeting = BYE;
                }
                messageReceived = false;
            }
        }


        /// <summary>
        /// 
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args) {
            AsyncUDPHostSample progn = new AsyncUDPHostSample();

            progn.run( args );
        }


        /// <summary>
        /// 
        /// </summary>
        private static bool messageSent = false;
        /// <summary>
        /// 
        /// </summary>
        private static bool messageReceived = false;
        /// <summary>
        /// 
        /// </summary>
        private static readonly string[] CONDITIONS = new string [] { "Pretty Good!", "Great!", "Not bad.", "Good!" };
        /// <summary>
        /// 
        /// </summary>
        private static readonly string BYE = "bye.";


        /// <summary>
        /// 
        /// </summary>
        private IPEndPoint remote_point_;
    }


}