与众不同 windows phone (33) Communication（通信）之源特定组播 SSM（Source Specific Multicast）

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与众不同 windows phone (33) - Communication（通信）之源特定组播 SSM（Source Specific Multicast）

作者：webabcd


介绍
与众不同 windows phone 7.5 (sdk 7.1) 之通信

• 实现“源特定多播” - SSM（Source Specific Multicast）

示例
1、服务端
Main.cs

/*
 * 此服务会定时向指定的多播组发送消息，用于演示 SSM
 */

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using System.Net;
using System.Net.Sockets;

namespace SocketServerSSM
{
    public partial class Main : Form
    {
        System.Threading.SynchronizationContext _syncContext;

        public Main()
        {
            InitializeComponent();

            LaunchSocketUdp();
        }

        private void LaunchSocketUdp()
        {
            _syncContext = System.Threading.SynchronizationContext.Current;

            // 定义 Source Specific Multicast 中的 Source，即 SSM 客户端仅接收此 Source 发送到多播组的数据
            IPEndPoint sourcePoint = new IPEndPoint(IPAddress.Any, 3370);

            // 定义多播组
            IPEndPoint multicastPoint = new IPEndPoint(IPAddress.Parse("224.0.1.2"), 3369);

            UdpClient sourceUdp = new UdpClient(sourcePoint);
            ShowMessage("用于演示 SSM 的 Socket 服务已启动，每 3 秒向多播组发送一次信息");


            // 每 3 秒向多播组发送一次信息
            var timer = new System.Timers.Timer();
            timer.Interval = 3000d;
            timer.Elapsed += delegate
            {
                string msg = string.Format("{0} - {1}", Dns.GetHostName(), DateTime.Now.ToString("HH:mm:ss"));
                byte[] data = Encoding.UTF8.GetBytes(msg);

                sourceUdp.Send(data, data.Length, multicastPoint);
            };
            timer.Start();
        }

        public void ShowMessage(string msg)
        {
            txtMsg.Text += msg + "\r\n";
        }
    }
}

2、客户端
实现 SSM 信道
UdpSingleSourceMulticastChannel.cs

/*
 * 实现一个 SSM 信道（即 SSM 帮助类），供外部调用
 * 
 * 
 * 通过 UdpSingleSourceMulticastClient 实现 SSM（Source Specific Multicast），即“源特定多播”
 * 多播组基于 IGMP（Internet Group Management Protocol），即“Internet组管理协议”
 * 
 * UdpSingleSourceMulticastClient - 一个从单一源接收多播信息的客户端，即 SSM 客户端
 *     BeginJoinGroup(), EndJoinGroup() - 加入“源”的异步方法
 *     BeginReceiveFromSource(), EndReceiveFromSource() - 从“源”接收信息的异步方法
 *     BeginSendToSource(), EndSendToSource() - 发送信息到“源”的异步方法
 *     ReceiveBufferSize - 接收信息的缓冲区大小
 *     SendBufferSize - 发送信息的缓冲区大小
 */

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using System.Net.Sockets;
using System.Text;

namespace Demo.Communication.SocketClient
{
    public class UdpSingleSourceMulticastChannel : IDisposable
    {
        // SSM 客户端
        private UdpSingleSourceMulticastClient _client;
        
        // “源”的地址
        private IPAddress _sourceAddress;

        // 接收信息的缓冲区
        private byte[] _buffer;
        // 此客户端是否加入了多播组
        private bool _isJoined;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="sourceAddress">SSM 的“源”的地址</param>
        /// <param name="groupAddress">多播组的地址</param>
        /// <param name="port">多播组的端口</param>
        /// <param name="maxMessageSize">接收信息的缓冲区大小</param>
        public UdpSingleSourceMulticastChannel(IPAddress sourceAddress, IPAddress groupAddress, int port, int maxMessageSize)
        {
            _sourceAddress = sourceAddress;
            _buffer = new byte[maxMessageSize];

            // 实例化 SSM 客户端，需要指定的参数为：“源”的地址；多播组的地址；多播组的端口
            _client = new UdpSingleSourceMulticastClient(sourceAddress, groupAddress, port);
        }

        // 收到多播信息后触发的事件
        public event EventHandler<UdpPacketEventArgs> Received;
        private void OnReceived(IPEndPoint source, byte[] data)
        {
            var handler = Received;
            if (handler != null)
                handler(this, new UdpPacketEventArgs(data, source));
        }

        // 加入多播组后触发的事件
        public event EventHandler Opening;
        private void OnOpening()
        {
            var handler = Opening;
            if (handler != null)
                handler(this, EventArgs.Empty);
        }

        // 断开多播组后触发的事件
        public event EventHandler Closing;
        private void OnClosing()
        {
            var handler = Closing;
            if (handler != null)
                handler(this, EventArgs.Empty);
        }

        /// <summary>
        /// 加入多播组
        /// </summary>
        public void Open()
        {
            if (!_isJoined)
            {
                _client.BeginJoinGroup(
                    result =>
                    {
                        _client.EndJoinGroup(result);
                        _isJoined = true;
                        Deployment.Current.Dispatcher.BeginInvoke(
                            () =>
                            {
                                OnOpening();
                                Receive();
                            });
                    }, null);
            }
        }

        /// <summary>
        /// 发送信息到“源”
        /// </summary>
        public void Send(string msg)
        {
            if (_isJoined)
            {
                byte[] data = Encoding.UTF8.GetBytes(msg);

                // 需要指定“源”的端口
                int sourcePort = 100;
                _client.BeginSendToSource(data, 0, data.Length, sourcePort,
                    result =>
                    {
                        _client.EndSendToSource(result);
                    }, null);
            }
        }

        /// <summary>
        /// 接收从多播组发过来的信息，即“源”发送给多播组的信息
        /// </summary>
        private void Receive()
        {
            if (_isJoined)
            {
                Array.Clear(_buffer, 0, _buffer.Length);

                _client.BeginReceiveFromSource(_buffer, 0, _buffer.Length,
                    result =>
                    {
                        int sourcePort;
                        // 接收到多播信息后，可获取到“源”的端口
                        _client.EndReceiveFromSource(result, out sourcePort);
                        Deployment.Current.Dispatcher.BeginInvoke(
                            () =>
                            {
                                OnReceived(new IPEndPoint(_sourceAddress, sourcePort), _buffer);
                                Receive();
                            });
                    }, null);
            }
        }

        // 关闭 SSM 信道
        public void Close()
        {
            _isJoined = false;
            OnClosing();
            Dispose();
        }

        public void Dispose()
        {
            if (_client != null)
                _client.Dispose();
        }
    }
}

演示 SSM
SourceSpecificMulticast.xaml

<phone:PhoneApplicationPage 
    x:Class="Demo.Communication.SocketClient.SourceSpecificMulticast"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    mc:Ignorable="d" d:DesignHeight="768" d:DesignWidth="480"
    shell:SystemTray.IsVisible="True">

    <Grid x:Name="LayoutRoot" Background="Transparent">
        <StackPanel HorizontalAlignment="Left">

            <ListBox Name="lstAllMsg" MaxHeight="400" />

        </StackPanel>
    </Grid>

</phone:PhoneApplicationPage>

SourceSpecificMulticast.xaml.cs

/*
 * 用于演示 SSM
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;

using System.Windows.Navigation;

namespace Demo.Communication.SocketClient
{
    public partial class SourceSpecificMulticast : PhoneApplicationPage
    {
        // 实例化自定义的 SSM 信道
        private UdpSingleSourceMulticastChannel _channel;

        public SourceSpecificMulticast()
        {
            InitializeComponent();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            // 多播组地址是必须介于 224.0.0.0 到 239.255.255.255 之间的 IP 地址，其中范围介于 224.0.0.0 到 224.0.0.255 之间的多播地址是保留多播地址
            // 比如：224.0.0.0 是基址，224.0.0.1 是代表同一个物理网络中所有系统的多播组地址，而 224.0.0.2 代表同一个物理网络中的所有路由器
            _channel = new UdpSingleSourceMulticastChannel(IPAddress.Parse("192.168.8.217"), IPAddress.Parse("224.0.1.2"), 3369, 2048);
            _channel.Opening += new EventHandler(_channel_Opening);
            _channel.Received += new EventHandler<UdpPacketEventArgs>(_channel_Received);
            _channel.Closing += new EventHandler(_channel_Closing);

            _channel.Open();

            // 需要的使用，应该调用 Close()
            // _channel.Close();
        }

        void _channel_Opening(object sender, EventArgs e)
        {
            lstAllMsg.Items.Insert(0, "已经连上多播组，等待来自多播组的消息");
        }

        void _channel_Received(object sender, UdpPacketEventArgs e)
        {
            // 因为已经指定了接收信息的缓冲区大小是 2048 ，所以如果信息不够 2048 个字节的的话，空白处均为空字节“\0”
            string message = string.Format("{0} - 来自：{1}", e.Message.TrimEnd('\0'), e.Source.ToString());
            lstAllMsg.Items.Insert(0, message);
        }

        void _channel_Closing(object sender, EventArgs e)
        {
            lstAllMsg.Items.Insert(0, "已经断开多播组");
        }
    }
}

OK
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