本篇继上一篇： Silverlight+WCF 网络象棋 终极篇 对战视频-上篇[客户端开启视频/注册编号/接收视频](五)

 一：对战视频 简单原理

二：对战视频 步骤解析：

三：对战视频 具体实施

1：如何打开视频

2：Silverlight如何使用Socket进行通讯

2.1：与远程建立链接：

2.2：注册编号[这里的规则是“房间号+棋手颜色值”]

2.3：开新线程，等待接收对方视频

2.4：将视频显示出来，需要用主线程来操作

3：图片压缩与视频发送

3.1：图片压缩

我们发送的视频，是通过定时器每秒截5张图发送过去的，每秒钟将产生5张图片，因此，图片压缩变的相当重要。

因此，找一种图片压缩算法，是一种开始：

一开始：是从网上down了个PngEncoder，压缩160*160的截图后，图片大小是40K，看成是4K[因为看字节时是4后面好多0,看少了一个0]，兴奋的我~~~

因此一开始在本地测试是正常的，上到网上就oh..no了。

40K*5，即每秒要发送200K的数据，这样就等于把2M/200K带宽给用光了，房东那限制的512K/56K带宽，就更提不上了~~~

最后：还是用上了大伙普通通用的JpgEncoder，压缩160*160的截图后，图片大小是10K，每秒产生10K*5=50K，56K带宽刚好够用了。

由于JpgEncoder为第三方插件，因此其代码就不贴了，下面简单介绍下：

1：JpgEncoder下载后内容为：FJ.Core.dll、JpgEncoder.cs两个文件。

2：JpgEncoder.cs有一静态方法，直接可以获取Stream流：

 public static Stream GetStream(WriteableBitmap bitmap)

3：没了~~~

ps:具体FJ.Core.dll、JpgEncoder.cs两个文件可以从下载源码下找到。

3.2 视频发送

为了定时发送视频，我们需要开启定时器：

        System.Windows.Threading.DispatcherTimer timer;//全局定义
         public MainPage()
        {
            InitializeComponent();
            timer = new System.Windows.Threading.DispatcherTimer();
            timer.Interval = TimeSpan.FromSeconds(0.2);//0.2秒一次，每秒5次
            timer.Tick += new EventHandler(timer_Tick);          
        }
        void timer_Tick(object sender, EventArgs e)
        {
           //这里就是发送视频的代码了
        }
        private void btnSend_Click(object sender, RoutedEventArgs e)
        {
            timer.Start();//点击发送视频时，启动定时器即可
        }

在点击发送触发定时器时，发送视频

        byte[] content = new byte[56 * 1024];
        int length;       
        void timer_Tick(object sender, EventArgs e)
        {
            WriteableBitmap img = new WriteableBitmap(canVideo, null);
            Stream stream = JpgEncoder.GetStream(img); //获取压缩后的流
            length = (int)stream.Length;
            stream.Read(content, 0, length);
            stream.Close();

            SocketAsyncEventArgs sendEvent = new SocketAsyncEventArgs();
            sendEvent.SetBuffer(content, 0, length);
            videoSocket.SendAsync(sendEvent);//这里只管发送，发送后的结果不管了。
           
            img = null;
        }

至此，客户端的一系列动作就完成了，包括[打开视频/注册编号/发送视频/接收视频]，下面到服务端代码上场了。

4：控制台服务端Socket中转

4.1：额外的处理事件

不过这两步，网上都有现成的代码，直接copy就可以了。

步骤如下：

1：新建控制台项目—》起名：TCPService

2：新建类文件：PolicyServer.cs，完整代码如下，大伙直接使用就可以了：

PolicyServer类与跨域xml文件

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

namespace TCPService
{
    class PolicyServer
    {
        Socket m_listenerIPv4;
        Socket m_listenerIPv6;
        byte[] m_policy;

        // pass in the path of an XML file containing the socket policy
        public PolicyServer(string policyContents)
        {
            m_policy = Encoding.UTF8.GetBytes(policyContents);

            // Create the Listening Sockets            
            m_listenerIPv4 = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            m_listenerIPv4.Bind(new IPEndPoint(IPAddress.Any, 943));
            m_listenerIPv4.Listen(10);
            m_listenerIPv4.BeginAccept(new AsyncCallback(OnConnection), m_listenerIPv4);
            //Console.WriteLine("Listenting on IPv4 port 943.");

            if (System.Net.Sockets.Socket.OSSupportsIPv6)
            {
                m_listenerIPv6 = new Socket(AddressFamily.InterNetworkV6, SocketType.Stream, ProtocolType.Tcp);
                m_listenerIPv6.Bind(new IPEndPoint(IPAddress.IPv6Any, 943));
                m_listenerIPv6.Listen(10);
                m_listenerIPv6.BeginAccept(new AsyncCallback(OnConnection), m_listenerIPv6);
                //Console.WriteLine("Listenting on IPv6 port 943.");
            }
            else
            {
               // Console.WriteLine("IPv6 is not supported by the system.");
            }
        }

        // Called when we receive a connection from a client
        public void OnConnection(IAsyncResult res)
        {
            Socket listener = (Socket)res.AsyncState;
            Socket client = null;

            try
            {
                client = listener.EndAccept(res);
            }
            catch (SocketException)
            {
                return;
            }

            // handle this policy request with a PolicyConnection
            PolicyConnection pc = new PolicyConnection(client, m_policy);

            // look for more connections
            listener.BeginAccept(new AsyncCallback(OnConnection), listener);
        }

        public void Close()
        {
            m_listenerIPv4.Close();
            if (m_listenerIPv6 != null)
            {
                m_listenerIPv6.Close();
            }
        }
    }
    class PolicyConnection
    {
        Socket m_connection;

        // buffer to receive the request from the client
        byte[] m_buffer;
        int m_received;

        // the policy to return to the client
        byte[] m_policy;

        // the request that we're expecting from the client
        static string s_policyRequestString = "<policy-file-request/>";

        public PolicyConnection(Socket client, byte[] policy)
        {
            m_connection = client;
            m_policy = policy;

            m_buffer = new byte[s_policyRequestString.Length];
            m_received = 0;

            try
            {
                // receive the request from the client
                m_connection.BeginReceive(m_buffer, 0, s_policyRequestString.Length, SocketFlags.None, new AsyncCallback(OnReceive), null);
            }
            catch (SocketException)
            {
                m_connection.Close();
            }
        }

        // Called when we receive data from the client
        private void OnReceive(IAsyncResult res)
        {
            try
            {
                m_received += m_connection.EndReceive(res);

                // if we haven't gotten enough for a full request yet, receive again
                if (m_received < s_policyRequestString.Length)
                {
                    m_connection.BeginReceive(m_buffer, m_received, s_policyRequestString.Length - m_received, SocketFlags.None, new AsyncCallback(OnReceive), null);
                    return;
                }

                // make sure the request is valid
                string request = System.Text.Encoding.UTF8.GetString(m_buffer, 0, m_received);
                if (StringComparer.InvariantCultureIgnoreCase.Compare(request, s_policyRequestString) != 0)
                {
                    m_connection.Close();
                    return;
                }

                // send the policy
                m_connection.BeginSend(m_policy, 0, m_policy.Length, SocketFlags.None, new AsyncCallback(OnSend), null);
            }
            catch (SocketException)
            {
                m_connection.Close();
            }
        }

        // called after sending the policy to the client; close the connection.
        public void OnSend(IAsyncResult res)
        {
            try
            {
                m_connection.EndSend(res);
            }
            finally
            {
                m_connection.Close();
            }
        }
    }
//跨域用的xml文件，以代码的方式传入。
public static class SocketPolicy
    {
        public const string Policy = @"
            <?xml version=""1.0"" encoding =""utf-8""?>
            <access-policy>
              <cross-domain-access>
                <policy>
                  <allow-from>
                    <domain uri=""*"" />
                  </allow-from>
                  <grant-to>
                    <socket-resource port=""4502-4530"" protocol=""tcp"" />
                  </grant-to>
                </policy>
              </cross-domain-access>
            </access-policy>
            ";
    }
}

3：控制台启动首行代码

至此，我们添加了个额外的处理类来解决943端口和跨域问题[注意上面代码中xml的端口号配置范围哦]，下面开始自己的服务端处理流程

4.2：服务端处理流程

4.2.1：开启监听

namespace TCPService
{
    class Program
    {
        public static Dictionary<int, ThreadProxy> soketList;//房号+颜色值
         static void Main(string[] args)
        {
            PolicyServer ps = new PolicyServer(SocketPolicy.Policy);//Silverlight跨域访问及943端口
            //主线程监听
            soketList = new Dictionary<int, ThreadProxy>();
            Console.WriteLine("TCPService正在启动运行");
            IPEndPoint ip = new IPEndPoint(IPAddress.Any, 4505);//本地任意IP及4505端口
            Socket mainSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            mainSocket.Bind(ip);
            mainSocket.Listen(-1);
            while (true)
            {
                Socket socket = mainSocket.Accept();
                new ThreadProxy(socket).Run();//收到消息即时处理。

            }
        }
        public static void WriteLine(string msg)
        {
            Console.WriteLine(msg);
        }
    }
    class ThreadProxy
    {
        public Socket socket;
        public ThreadProxy(Socket newSocket)
        {
            socket = newSocket;
        }
        public void Run()
        {
            Thread thread = new Thread(new ThreadStart(Action));
            thread.Start();
        }
        public void Action()
        {
            Program.WriteLine("有人来了----");
            //下面开启处理逻辑
        }
   }
}

说明：

4.2.2 定义下全局变量

        public Socket socket;//我方的Socket
        ThreadProxy youThreadProxy;//对方

        int num;//注册的编号

        byte[] buffer = new byte[30 * 1024];//缓冲字节30K，简单说就是用户10K发送3次，这里收到满30K才转发一次
        bool firstConn = true;//是否第一次建立链接，首次链接都是注册编号，不发送视频的；

4.2.3 处理编号注册、移除、查找对方

编号注册：

        private void RegSocket(string key)
        {
            firstConn = false;//注册完后，设置下标识
            if (key.Length < 10)//字节太多就是图片流了
            {
                if (int.TryParse(key, out num))
                {
                    if (Program.soketList.ContainsKey(num))//之前都有人在了
                       {
                        Program.soketList[num].socket.Close();
                        Program.soketList[num].socket.Dispose();
                        Program.soketList.Remove(num);
                    }
                    Program.soketList.Add(num, this);
                    Program.WriteLine("用户注册:" + key);
                    FindYouSocket();
                    return;
                }
            }
        }

线程错误，编号移除：

       private void OnError(ThreadProxy errorProxy,string errorMsg)
        {
            if (errorProxy.socket != null)
            {
                errorProxy.socket.Close();
            }
            Console.WriteLine("删除用户:" + errorProxy.num +"错误信息:"+ errorMsg);
            Program.soketList.Remove(errorProxy.num);
            
        }

查询对方：

       private void FindYouSocket()
       {
            int youNum = num % 2 == 0 ? num - 1 : num + 1;
            if (Program.soketList.ContainsKey(youNum))
            {
                youThreadProxy = Program.soketList[youNum];
            }
         }

4.2.4 主业务处理中转流程

       public ThreadProxy(Socket newSocket)
        {
            socket = newSocket;
            socket.SendBufferSize = buffer.Length;
            socket.ReceiveBufferSize = buffer.Length;
        }
        public void Run()
        {
            Thread thread = new Thread(new ThreadStart(Action));
            thread.Start();
        }
        public void Action()
        {
            Program.WriteLine("有人来了----");
            try
            {
                while (true)
                {
                    if (socket.Connected)
                    {
                        int length = 0, count = 0;
                        do
                        {
                            System.Threading.Thread.Sleep(20);//关键点,请求太快数据接收不全
                            length = socket.Receive(buffer, count, socket.Available, 0);
                            count = count + length;

                        }
                        while (socket.Available > 0);

                        if (count > 1)
                        {

                            if (count < 4)//小字节，命令字符
                            {
                                if (firstConn)//首次登陆，需要注册ID
                                {
                                    string key = ASCIIEncoding.ASCII.GetString(buffer, 0, count);
                                    RegSocket(key);
                                }
                            }
                            else if (youThreadProxy == null)
                            {
                                Program.WriteLine("没人接收。。。");
                                FindYouSocket();
                            }
                            else if (youThreadProxy.canReceive)//对方允许接收图片发送
                                {
                                Program.WriteLine("图片来了:" + count);
                                if (youThreadProxy.socket.Connected)
                                {
                                    Program.WriteLine("图片转发:" + buffer.Length);
                                    try
                                    {
                                        youThreadProxy.socket.Send(buffer, count, 0);
                                    }
                                    catch(Exception err)
                                    {
                                        OnError(youThreadProxy, err.Message);
                                    }
                                }
                            }
                        }
                    }
                    else
                    {
                        OnError(this,"socket链接已关闭");
                        break;
                    }
                }
            }
            catch(Exception err)
            {
                OnError(this,err.Message);
            }

        }

处理流程也很简单，根据请求的字节大小来调用是“注册”还是“中转”。

至此，整个完整的视频传输篇完成了，完成的图片和上一节一样了：

最后是大家期待已久的示例源码下载：下载中心

说明：视频源码中的内容会多一些，包括一开始我写的一些其它杂七杂八的代码，不过不影响整个的运行。