Unity-Socket通信实例详解

今天我们来讲解socket通信。

首先我们需要知道什么是socket通信：

Socket本质上就是一个个进程之间网络通信的基础，每一个Socket由IP+端口组成，熟悉计网的同学应该知道IP主要是应用于IP协议而端口主要应用于TCP协议，这也证明了Socket通信是一个多个层共同工作的过程。

总结：Socket是网络编程的基石，通过简单API抽象底层协议，实现进程间灵活高效的数据交换。

现在我们用一个实例来看看具体的一个Socket通信是如何实现的，既然涉及到了网络通信，那当然需要一个客户端和一个服务器，我们就拿自己的电脑来同时作为客户端和服务器即可。

Server

我们从服务器开始。

首先来看一个大体服务器代码的作用：

Main

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class Main : MonoBehaviour
{SocketServer _server;private void Awake(){_server = new SocketServer("127.0.0.1", 6854);_server.OnConnect += (client) =>{UnityEngine.Debug.LogFormat("连接成功 >> IP:{0}", client.LocalEndPoint.ToString());};_server.OnDisconnect += (client) =>{UnityEngine.Debug.LogFormat("连接断开 >> IP:{0}", client.LocalEndPoint.ToString());};_server.OnReceive += (client, data) =>{UnityEngine.Debug.LogFormat("[{0}]接收到数据>>>{1} {2}", client.LocalEndPoint.ToString(), (SocketEvent)data.Type, data.Buff.Length);switch ((SocketEvent)data.Type){case SocketEvent.sc_test:UnityEngine.Debug.LogFormat("接收到测试数据 >>> {0}", System.Text.Encoding.UTF8.GetString(data.Data));break;}};}private void Update(){if (Input.GetKeyDown(KeyCode.A)){// 踢出连接foreach (var item in _server.ClientInfoDic.Keys){_server.KickOutAll();}}}private void OnDestroy(){// 注意由于Unity编译器环境下，游戏开启/关闭只影响主线程的开关，游戏关闭回调时需要通过Close函数来关闭服务端/客户端的线程。if (_server != null){_server.Close();}}
}

光看这一段代码的话其实也看不出什么名堂，我们只知道有一个SocketServer类的实例_server，我们在Awake（）函数中_server分别注册了三个事件，分别对应连接、断连和接受信息。在Update中我们如果检测到按键A我们把_server中的客户端信息全部清空，以及最后关闭服务器。

那显然我们的重心是来看看SocketServer类的代码内容了。

SocketServer

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Timers;public class SocketInfo
{public Socket Client;public Thread ReceiveThread;public long HeadTime;
}/// <summary>
/// Socket服务端
/// </summary>
public class SocketServer
{/// <summary>/// 主线程/// </summary>private SynchronizationContext _mainThread;public string IP;public int Port;private const int HEAD_TIMEOUT = 5000;    // 心跳超时 毫秒private const int HEAD_CHECKTIME = 5000;   // 心跳包超时检测 毫秒public Dictionary<Socket, SocketInfo> ClientInfoDic = new Dictionary<Socket, SocketInfo>();private Socket _server;private Thread _connectThread;private System.Timers.Timer _headCheckTimer;private DataBuffer _dataBuffer = new DataBuffer();public event Action<Socket> OnConnect;  //客户端建立连接回调public event Action<Socket> OnDisconnect;  // 客户端断开连接回调public event Action<Socket, SocketDataPack> OnReceive;  // 接收报文回调public event Action<Socket, SocketDataPack> OnSend;  // 发送报文回调// 目前捕获异常将触发OnDisconnect回调 暂不单独处理// public event Action<SocketException> OnError;   // 异常捕获回调private bool _isValid = true;public SocketServer(string ip, int port){_mainThread = SynchronizationContext.Current;IP = ip;Port = port;_server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);IPAddress ipAddress = IPAddress.Parse(IP);//解析IP地址_server.Bind(new IPEndPoint(ipAddress, Port));  //绑定IP地址：端口  _server.Listen(10);    //设定最多10个排队连接请求// 启动线程监听连接_connectThread = new Thread(ListenClientConnect);_connectThread.Start();// 心跳包定时检测_headCheckTimer = new System.Timers.Timer(HEAD_CHECKTIME);_headCheckTimer.AutoReset = true;_headCheckTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){CheckHeadTimeOut();};_headCheckTimer.Start();}/// <summary>  /// 监听客户端连接  /// </summary>  private void ListenClientConnect(){while (true){try{if (!_isValid) break;Socket client = _server.Accept();Thread receiveThread = new Thread(ReceiveEvent);ClientInfoDic.Add(client, new SocketInfo() { Client = client, ReceiveThread = receiveThread, HeadTime = GetNowTime() });receiveThread.Start(client);PostMainThreadAction<Socket>(OnConnect, client);}catch{break;}}}/// <summary>/// 获取当前时间戳/// </summary>/// <returns></returns>private long GetNowTime(){TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);return Convert.ToInt64(ts.TotalMilliseconds);}public void Send(Socket client, UInt16 e, byte[] buff = null, Action<SocketDataPack> onTrigger = null){buff = buff ?? new byte[] { };var dataPack = new SocketDataPack(e, buff);var data = dataPack.Buff;try{client.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback((asyncSend) =>{Socket c = (Socket)asyncSend.AsyncState;c.EndSend(asyncSend);PostMainThreadAction<SocketDataPack>(onTrigger, dataPack);PostMainThreadAction<Socket, SocketDataPack>(OnSend, client, dataPack);}), client);}catch (SocketException ex){CloseClient(client);// onError(ex);}}/// <summary>/// 线程内接收数据的函数/// </summary>private void ReceiveEvent(object client){Socket tsocket = (Socket)client;while (true){if (!_isValid) return;if (!ClientInfoDic.ContainsKey(tsocket)){return;}try{byte[] rbytes = new byte[8 * 1024];int len = tsocket.Receive(rbytes);if (len > 0){_dataBuffer.AddBuffer(rbytes, len); // 将收到的数据添加到缓存器中var dataPack = new SocketDataPack();if (_dataBuffer.TryUnpack(out dataPack)) // 尝试解包{if (dataPack.Type == (UInt16)SocketEvent.sc_head){// 接收到心跳包ReceiveHead(tsocket);}else if (dataPack.Type == (UInt16)SocketEvent.sc_disconn){// 客户端断开连接CloseClient(tsocket);}else{// 收到消息PostMainThreadAction<Socket, SocketDataPack>(OnReceive, tsocket, dataPack);}}}else{if (tsocket.Poll(-1, SelectMode.SelectRead)){CloseClient(tsocket);return;}}}catch (SocketException ex){CloseClient(tsocket);// onError(ex);return;}}}/// <summary>/// 接收到心跳包/// </summary>private void ReceiveHead(Socket client){SocketInfo info;if (ClientInfoDic.TryGetValue(client, out info)){long now = GetNowTime();long offset = now - info.HeadTime;UnityEngine.Debug.Log("更新心跳时间戳 >>>" + now + "  间隔>>>" + offset);if (offset > HEAD_TIMEOUT){// 心跳包收到但超时逻辑}info.HeadTime = now;}}/// <summary>/// 检测心跳包超时/// </summary>private void CheckHeadTimeOut(){var tempList = new List<Socket>();foreach (var socket in ClientInfoDic.Keys){tempList.Add(socket);}foreach (var socket in tempList){var info = ClientInfoDic[socket];long now = GetNowTime();long offset = now - info.HeadTime;if (offset > HEAD_TIMEOUT){// 心跳包超时KickOut(socket);}}}public void KickOut(Socket client){// 踢出连接Send(client, (UInt16)SocketEvent.sc_kickout, null, (dataPack) =>{CloseClient(client);});}public void KickOutAll(){var tempList = new List<Socket>();foreach (var socket in ClientInfoDic.Keys){tempList.Add(socket);}foreach (var socket in tempList){KickOut(socket);}}/// <summary>/// 清理客户端连接/// </summary>/// <param name="client"></param>private void CloseClient(Socket client){PostMainThreadAction<Socket>((socket) =>{if (OnDisconnect != null) OnDisconnect(socket);ClientInfoDic.Remove(socket);socket.Close();}, client);}/// <summary>/// 关闭/// </summary>public void Close(){if (!_isValid) return;_isValid = false;// if (_connectThread != null) _connectThread.Abort();var tempList = new List<Socket>();foreach (var socket in ClientInfoDic.Keys){tempList.Add(socket);}foreach (var socket in tempList){CloseClient(socket);}if (_headCheckTimer != null){_headCheckTimer.Stop();_headCheckTimer = null;}_server.Close();}// /// <summary>// /// 错误回调// /// </summary>// /// <param name="e"></param>// private void onError(SocketException ex)// {//     PostMainThreadAction<SocketException>(OnError, ex);// }// <summary>/// 通知主线程回调/// </summary>private void PostMainThreadAction(Action action){_mainThread.Post(new SendOrPostCallback((o) =>{Action e = (Action)o.GetType().GetProperty("action").GetValue(o);if (e != null) e();}), new { action = action });}private void PostMainThreadAction<T>(Action<T> action, T arg1){_mainThread.Post(new SendOrPostCallback((o) =>{Action<T> e = (Action<T>)o.GetType().GetProperty("action").GetValue(o);T t1 = (T)o.GetType().GetProperty("arg1").GetValue(o);if (e != null) e(t1);}), new { action = action, arg1 = arg1 });}public void PostMainThreadAction<T1, T2>(Action<T1, T2> action, T1 arg1, T2 arg2){_mainThread.Post(new SendOrPostCallback((o) =>{Action<T1, T2> e = (Action<T1, T2>)o.GetType().GetProperty("action").GetValue(o);T1 t1 = (T1)o.GetType().GetProperty("arg1").GetValue(o);T2 t2 = (T2)o.GetType().GetProperty("arg2").GetValue(o);if (e != null) e(t1, t2);}), new { action = action, arg1 = arg1, arg2 = arg2 });}
}

非常长的代码内容啊，我们一点一点来看：

public class SocketInfo
{public Socket Client;public Thread ReceiveThread;public long HeadTime;
}

这是我们的Socket的信息，可以看到有Socket类的实例，对于服务器来说要处理的Socket类当然就是客户端的Socket，有一个线程和一个时间值，这个时间值的作用我们暂时按下不表。

    /// <summary>/// 主线程/// </summary>private SynchronizationContext _mainThread;public string IP;public int Port;private const int HEAD_TIMEOUT = 5000;    // 心跳超时 毫秒private const int HEAD_CHECKTIME = 5000;   // 心跳包超时检测 毫秒public Dictionary<Socket, SocketInfo> ClientInfoDic = new Dictionary<Socket, SocketInfo>();private Socket _server;private Thread _connectThread;private System.Timers.Timer _headCheckTimer;private DataBuffer _dataBuffer = new DataBuffer();public event Action<Socket> OnConnect;  //客户端建立连接回调public event Action<Socket> OnDisconnect;  // 客户端断开连接回调public event Action<Socket, SocketDataPack> OnReceive;  // 接收报文回调public event Action<Socket, SocketDataPack> OnSend;  // 发送报文回调// 目前捕获异常将触发OnDisconnect回调 暂不单独处理// public event Action<SocketException> OnError;   // 异常捕获回调private bool _isValid = true;

可以看到密密麻麻的一系列参数啊，这里就是我们SocketServer类的成员变量了，首先是这个我们似乎第一次见的类：SynchronizationContext。

看名字也知道这个类和异步操作以及上下文有关系，概括来说：

然后是我们的IP和端口，这个不多说。然后是两个int时间值，还记得之前SocketInfo里定义的HeadTime吗？我们称其为心跳时间：

那在一个Socket网络通信中心跳时间的意义不用多说了吧，就是检查连接是否正常的一个时间阈值，具体是怎么个检查法我们后续介绍。

然后是一个存储客户端Socket信息的字典，代表服务器的Socket类实例，一个线程，一个计时器，然后是一个数据缓冲类（自定义的），然后是一系列event（大家应该都知道什么是event吧？），更准确的说是Action，分别代表连接，断连，接收和发送。最后一个bool变量表示能否建立连接。

    public SocketServer(string ip, int port){_mainThread = SynchronizationContext.Current;IP = ip;Port = port;_server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);IPAddress ipAddress = IPAddress.Parse(IP);//解析IP地址_server.Bind(new IPEndPoint(ipAddress, Port));  //绑定IP地址：端口  _server.Listen(10);    //设定最多10个排队连接请求// 启动线程监听连接_connectThread = new Thread(ListenClientConnect);_connectThread.Start();// 心跳包定时检测_headCheckTimer = new System.Timers.Timer(HEAD_CHECKTIME);_headCheckTimer.AutoReset = true;_headCheckTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){CheckHeadTimeOut();};_headCheckTimer.Start();}

SocketServer的有参构造，参数是IP和端口号。

我们把当前线程上下文给到_mainThread，IP和端口也给到。然后是服务器的初始化：

        _headCheckTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){CheckHeadTimeOut();};

这一系列初始化服务器的操作都是在调用Socket类内部的函数。

然后是启动我们线程的监听状态，然后启动我们的心跳包定时检测，注意我们在new一个计时器的构造函数的参数：

_headCheckTimer = new System.Timers.Timer(HEAD_CHECKTIME);

这里的HEAD_CHECKTIME代表时间间隔。

我们开启计时器的自动重置之后可以看到：

        _headCheckTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){CheckHeadTimeOut();};

这是一个匿名委托：用法类似于匿名函数，我们直接写委托内容，随写随用，每次委托触发时执行CheckHeadTimeOut()函数。

这个过程中涉及到两个函数：

    /// <summary>  /// 监听客户端连接  /// </summary>  private void ListenClientConnect(){while (true){try{if (!_isValid) break;Socket client = _server.Accept();Thread receiveThread = new Thread(ReceiveEvent);ClientInfoDic.Add(client, new SocketInfo() { Client = client, ReceiveThread = receiveThread, HeadTime = GetNowTime() });receiveThread.Start(client);PostMainThreadAction<Socket>(OnConnect, client);}catch{break;}}}

用try catch避免异常，从服务器处获取接受的客户端Socket类和线程，这里可以看到构造新线程的参数为ReceiveEvent，代表这个线程构造时就会绑定一个委托。

   /// <summary>/// 检测心跳包超时/// </summary>private void CheckHeadTimeOut(){var tempList = new List<Socket>();foreach (var socket in ClientInfoDic.Keys){tempList.Add(socket);}foreach (var socket in tempList){var info = ClientInfoDic[socket];long now = GetNowTime();long offset = now - info.HeadTime;if (offset > HEAD_TIMEOUT){// 心跳包超时KickOut(socket);}}}

这个是我们在构造函数中关于心跳包超时检测的函数，我们创建一个存储Socket的list，把存储客户端信息的字典中的键更新到list中，然后获取当前时间之后减去客户端socket信息之中的HeadTime来得到时间偏差，如果这个时间偏差大于我们的允许的时间值我们就认为这个心跳包超时并执行KickOut函数。

这里又涉及到了两个函数：GetNowTime()和KickOut()；

   /// <summary>/// 获取当前时间戳/// </summary>/// <returns></returns>private long GetNowTime(){TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);return Convert.ToInt64(ts.TotalMilliseconds);}

这一段代码是一个获取当前时间的方法：

而关于KickOut():

    public void KickOut(Socket client){// 踢出连接Send(client, (UInt16)SocketEvent.sc_kickout, null, (dataPack) =>{CloseClient(client);});}

似乎牵扯的函数越来越多了，我们来看看Send是什么：

    public void Send(Socket client, UInt16 e, byte[] buff = null, Action<SocketDataPack> onTrigger = null){buff = buff ?? new byte[] { };var dataPack = new SocketDataPack(e, buff);var data = dataPack.Buff;try{client.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback((asyncSend) =>{Socket c = (Socket)asyncSend.AsyncState;c.EndSend(asyncSend);PostMainThreadAction<SocketDataPack>(onTrigger, dataPack);PostMainThreadAction<Socket, SocketDataPack>(OnSend, client, dataPack);}), client);}catch (SocketException ex){CloseClient(client);// onError(ex);}}

回到我们的KickOut()函数：

我们实现了一个异步的解除客户端连接的方法：我们向客户端发送事件码告知其断开连接之后不会阻塞当前线程。

然后就是两个负责关闭连接的函数：

    private void CloseClient(Socket client){PostMainThreadAction<Socket>((socket) =>{if (OnDisconnect != null) OnDisconnect(socket);ClientInfoDic.Remove(socket);socket.Close();}, client);}

这是关闭客户端连接的代码，其中的PostMainThreadAction<Socket>：

的作用就是把这个Socket类型的实例放在主线程上进行操作。操作的内容包括检查是否有方法注册在OnDisconnect上，有的话就执行；然后从字典中删除相关Socket信息，关闭相关socket即可。

这里可能涉及到一个问题就是：为什么我们Socket的关闭一定要在主线程上执行呢？

   /// <summary>/// 关闭/// </summary>public void Close(){if (!_isValid) return;_isValid = false;// if (_connectThread != null) _connectThread.Abort();var tempList = new List<Socket>();foreach (var socket in ClientInfoDic.Keys){tempList.Add(socket);}foreach (var socket in tempList){CloseClient(socket);}if (_headCheckTimer != null){_headCheckTimer.Stop();_headCheckTimer = null;}_server.Close();}

这个是关闭整个服务器的函数，我们把所有的客户端socket先关闭掉，然后停止计时器后最后关闭服务器。

这个是整个SocketServer类的内容，其中还有几个自定义类的内容我们没有介绍：

DataBuffer

代码如下：

using System;
/// <summary>
/// Socket传输过程的缓冲区，尝试拆包获得数据
/// </summary>
public class DataBuffer
{// 缓存区长度private const int MIN_BUFF_LEN = 1024;private byte[] _buff;private int _buffLength = 0;public DataBuffer(int minBuffLen = MIN_BUFF_LEN){if (minBuffLen <= 0){minBuffLen = MIN_BUFF_LEN;}_buff = new byte[minBuffLen];}/// <summary>/// 添加缓存数据/// </summary>public void AddBuffer(byte[] data, int len){byte[] buff = new byte[len];Array.Copy(data, buff, len);if (len > _buff.Length - _buffLength)  //超过当前缓存{byte[] temp = new byte[_buffLength + len];Array.Copy(_buff, 0, temp, 0, _buffLength);Array.Copy(buff, 0, temp, _buffLength, len);_buff = temp;}else{Array.Copy(data, 0, _buff, _buffLength, len);}_buffLength += len;//修改当前数据标记}public bool TryUnpack(out SocketDataPack dataPack){dataPack = SocketDataPack.Unpack(_buff);if (dataPack == null){return false;}// 清理旧缓存_buffLength -= dataPack.BuffLength;byte[] temp = new byte[_buffLength < MIN_BUFF_LEN ? MIN_BUFF_LEN : _buffLength];Array.Copy(_buff, dataPack.BuffLength, temp, 0, _buffLength);_buff = temp;return true;}
}

我们来一点点解读：

    // 缓存区长度private const int MIN_BUFF_LEN = 1024;private byte[] _buff;private int _buffLength = 0;

定义了缓冲区的长度：注意这里的长度针对的是字节数，也就是至少1024个字节的缓冲区大小，其实也就是初始的缓冲区大小，一个字节数组和一个当前缓冲区长度。

    public DataBuffer(int minBuffLen = MIN_BUFF_LEN){if (minBuffLen <= 0){minBuffLen = MIN_BUFF_LEN;}_buff = new byte[minBuffLen];}

public的构造函数，给参数提供了默认参数，构造时自动生成一个设定好大小的字节数组。

    /// <summary>/// 添加缓存数据/// </summary>public void AddBuffer(byte[] data, int len){byte[] buff = new byte[len];Array.Copy(data, buff, len);if (len > _buff.Length - _buffLength)  //超过当前缓存{byte[] temp = new byte[_buffLength + len];Array.Copy(_buff, 0, temp, 0, _buffLength);Array.Copy(buff, 0, temp, _buffLength, len);_buff = temp;}else{Array.Copy(data, 0, _buff, _buffLength, len);}_buffLength += len;//修改当前数据标记}

我们新生成一个长度为len的数组，然后把data数组拷贝到buff中，如果这个时候我们的len超过了缓冲区的大小我们需要去新开辟一个数组并把现有的数据拷贝到新开辟的数组中；否则我们直接复制即可，然后修改缓冲区长度。这里有一个C#的内置函数Copy。

最后的一个函数：

    public bool TryUnpack(out SocketDataPack dataPack){dataPack = SocketDataPack.Unpack(_buff);if (dataPack == null){return false;}// 清理旧缓存_buffLength -= dataPack.BuffLength;byte[] temp = new byte[_buffLength < MIN_BUFF_LEN ? MIN_BUFF_LEN : _buffLength];Array.Copy(_buff, dataPack.BuffLength, temp, 0, _buffLength);_buff = temp;return true;}

这是一个拆包的函数，我们将缓冲区的Socket数据包进行拆包，如果包是空的则返回false（表示缓冲区内数据不足，无法组成完整的包），否则将数据从缓冲区移除，具体来说首先更新缓冲区大小，检查缓冲区剩余容量保证不低于最低容量，将未使用的缓冲数据从后续位置移动（复制到）缓冲区前端方便使用。

可以看到这个函数中有一个我们没有说过的SocketDataPack类。

SocketDataPack

Socket数据包的代码如下，以下简称数据包。

using System;
using System.IO;
/// <summary>
/// Socket通信过程中的数据包 处理具体拆包装包逻辑
/// </summary>
public class SocketDataPack
{// 消息：数据总长度(4byte) + 数据类型(2byte) + 数据(N byte)public static int HEAD_DATA_LEN = 4;public static int HEAD_TYPE_LEN = 2;public static int HEAD_LEN{get { return HEAD_DATA_LEN + HEAD_TYPE_LEN; }}/// <summary>/// 数据包类型/// </summary>public UInt16 Type;/// <summary>/// 数据包数据/// </summary>public byte[] Data;public byte[] Buff;public int BuffLength{get { return Buff.Length; }}public int DataLength{get { return Data.Length; }}public SocketDataPack(){}public SocketDataPack(UInt16 type, byte[] data){Type = type;Data = data;Buff = GetBuff(Type, Data);}public static byte[] GetBuff(UInt16 type, byte[] data){byte[] buff = new byte[data.Length + HEAD_LEN];byte[] temp;temp = BitConverter.GetBytes(buff.Length);Array.Copy(temp, 0, buff, 0, HEAD_DATA_LEN);temp = BitConverter.GetBytes(type);Array.Copy(temp, 0, buff, HEAD_DATA_LEN, HEAD_TYPE_LEN);Array.Copy(data, 0, buff, HEAD_LEN, data.Length);return buff;}public static SocketDataPack Unpack(byte[] buff){try{if (buff.Length < HEAD_LEN){// 头部没取完则返回return null;}byte[] temp;// 取数据长度temp = new byte[HEAD_DATA_LEN];Array.Copy(buff, 0, temp, 0, HEAD_DATA_LEN);int buffLength = BitConverter.ToInt32(temp, 0);if (buffLength <= 0) return null;if (buffLength > buff.Length){// 数据没取完return null;}int dataLength = buffLength - HEAD_LEN;// 取数据类型temp = new byte[HEAD_TYPE_LEN];Array.Copy(buff, HEAD_DATA_LEN, temp, 0, HEAD_TYPE_LEN);UInt16 dataType = BitConverter.ToUInt16(temp, 0);// 取数据byte[] data = new byte[dataLength];Array.Copy(buff, HEAD_LEN, data, 0, dataLength);var dataPack = new SocketDataPack(dataType, data);// UnityEngine.Debug.LogFormat("buffLen:{0} type:{1} dataLength:{2}", buffLength, dataType, data.Length);return dataPack;}catch{// 存在不完整数据解包 则返回nullreturn null;}}
}

首先看看成员变量：

    // 消息：数据总长度(4byte) + 数据类型(2byte) + 数据(N byte)public static int HEAD_DATA_LEN = 4;public static int HEAD_TYPE_LEN = 2;public static int HEAD_LEN{get { return HEAD_DATA_LEN + HEAD_TYPE_LEN; }}/// <summary>/// 数据包类型/// </summary>public UInt16 Type;/// <summary>/// 数据包数据/// </summary>public byte[] Data;public byte[] Buff;

定义了数据包的格式：数据长度为4，类型长度为2，然后是数据本身，设置为一个只读的属性，长度为前二者之和。

数据包类型使用一个UInt16的数据类型来表示，数据分为Data和Buff两种。

    public int BuffLength{get { return Buff.Length; }}public int DataLength{get { return Data.Length; }}

这两个也是只读的属性，返回的是Data和Buff类型数据的长度。

    public SocketDataPack(UInt16 type, byte[] data){Type = type;Data = data;Buff = GetBuff(Type, Data);}

有参构造，参数就是类型和数据，然后缓冲由GetBuff函数得到。

    public static byte[] GetBuff(UInt16 type, byte[] data){byte[] buff = new byte[data.Length + HEAD_LEN];byte[] temp;temp = BitConverter.GetBytes(buff.Length);Array.Copy(temp, 0, buff, 0, HEAD_DATA_LEN);temp = BitConverter.GetBytes(type);Array.Copy(temp, 0, buff, HEAD_DATA_LEN, HEAD_TYPE_LEN);Array.Copy(data, 0, buff, HEAD_LEN, data.Length);return buff;}

GetBuff函数就是一个根据类型和数据来获取缓冲的函数，我们新生成一个长度为数据长度加上头部长度的数组，然后我们使用BitConverter.GetBytes函数来生成字节流之后把这些字节流丢到中，更准确地说，我们把缓冲区的长度信息，类型信息（都转换为字节流）以及具体的数据都拷贝到数组中。

关于为什么要转换为字节流：

public static SocketDataPack Unpack(byte[] buff)
{try{if (buff.Length < HEAD_LEN){// 头部没取完则返回return null;}byte[] temp;// 取数据长度temp = new byte[HEAD_DATA_LEN];Array.Copy(buff, 0, temp, 0, HEAD_DATA_LEN);int buffLength = BitConverter.ToInt32(temp, 0);if (buffLength <= 0) return null;if (buffLength > buff.Length){// 数据没取完return null;}int dataLength = buffLength - HEAD_LEN;// 取数据类型temp = new byte[HEAD_TYPE_LEN];Array.Copy(buff, HEAD_DATA_LEN, temp, 0, HEAD_TYPE_LEN);UInt16 dataType = BitConverter.ToUInt16(temp, 0);// 取数据byte[] data = new byte[dataLength];Array.Copy(buff, HEAD_LEN, data, 0, dataLength);var dataPack = new SocketDataPack(dataType, data);// UnityEngine.Debug.LogFormat("buffLen:{0} type:{1} dataLength:{2}", buffLength, dataType, data.Length);return dataPack;}catch{// 存在不完整数据解包 则返回nullreturn null;}}

这里是我们数据包的拆包函数，参数是一个字节数组，我们首先检测这个数组长度如果没有头部长度大的话说明这个数组的内容根本不完整，直接返回null。接着我们分别从参数传递的数组中取长度信息、类型信息以及数据本身，将其复制到数组中，最后生成SocketDataPack类型的数据包并返回。

小小的总结一下我们的Server代码的作用：

对于我们的服务器来说，最重要的部分是通过心跳包来检查连接是否正常，以及接收信息之后的各种回调事件。

Client

客户端这边的DataBuffer和SocketDataPack的内容是完全相同的，主要是Main和SocketClient的区别：

Main

内容如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;public class Main : MonoBehaviour
{SocketClient _client;private void Awake(){_client = new SocketClient("127.0.0.1", 6854);_client.OnDisconnect += () =>{UnityEngine.Debug.Log("断开连接");};_client.OnReceive += (dataPack) =>{UnityEngine.Debug.LogFormat("接收数据>>>{0}", (SocketEvent)dataPack.Type);};_client.OnSend += (dataPack) =>{UnityEngine.Debug.LogFormat("发送数据>>>{0}", (SocketEvent)dataPack.Type);};_client.OnError += (ex) =>{UnityEngine.Debug.LogFormat("出现异常>>>{0}", ex);};_client.OnReConnectSuccess += (num) =>{UnityEngine.Debug.LogFormat("第{0}次重连成功", num);};_client.OnReConnectError += (num) =>{UnityEngine.Debug.LogFormat("第{0}次重连失败", num);};_client.OnReconnecting += (num) =>{UnityEngine.Debug.LogFormat("正在进行第{0}次重连", num);};_client.Connect(() =>{UnityEngine.Debug.Log("连接成功");// _client.DisConnect();}, () =>{UnityEngine.Debug.Log("连接失败");});}private void Update(){}public void ClickSendTest(){var bytes = System.Text.Encoding.UTF8.GetBytes("我是测试数据");_client.Send((System.UInt16)SocketEvent.sc_test, bytes);}public void ClickDisConnect(){_client.DisConnect();}private void OnDestroy(){// 注意由于Unity编译器环境下，游戏开启/关闭只影响主线程的开关，游戏关闭回调时需要通过Close函数来关闭服务端/客户端的线程。if (_client != null){_client.Close();}}
}

可以看到客户端的Main函数内容多得多。

首先是一个SocketClient类的实例，然后就是一系列的委托事件，分别代表：断开连接、接受消息、发送消息、发现错误、第num次重连成功、第num次重连失败、正在进行第num次重连。

然后是一个关于连接成功与否的包含两个lambda参数的方法：将是否连接成功打印出来。

然后是三个函数：点击发送测试消息、点击断开连接、关闭客户端socket。

SocketClient

这是客户端的Socket代码：

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System.Timers;/// <summary>
/// Socket客户端
/// </summary>
public class SocketClient
{/// <summary>/// 主线程/// </summary>private SynchronizationContext _mainThread;public string IP;public int Port;private const int TIMEOUT_CONNECT = 3000;   // 连接超时时间 毫秒private const int TIMEOUT_SEND = 3000;  // 发送超时时间 毫秒private const int TIMEOUT_RECEIVE = 3000;   //接收超时时间 毫秒private const int HEAD_OFFSET = 2000; //心跳包发送间隔 毫秒private const int RECONN_MAX_SUM = 3;   //最大重连次数private Socket _client;private Thread _receiveThread;private System.Timers.Timer _connTimeoutTimer;private System.Timers.Timer _headTimer;private DataBuffer _dataBuffer = new DataBuffer();public event Action OnConnectSuccess;    // 连接成功回调public event Action OnConnectError;    // 连接失败回调public event Action OnDisconnect;  // 断开回调public event Action<SocketDataPack> OnReceive;  // 接收报文回调public event Action<SocketDataPack> OnSend;  // 发送报文回调public event Action<SocketException> OnError;   // 异常捕获回调public event Action<int> OnReConnectSuccess; // 重连成功回调public event Action<int> OnReConnectError; // 单次重连失败回调public event Action<int> OnReconnecting;  // 单次重连中回调private bool _isConnect = false;private bool _isReconnect = false;public SocketClient(string ip, int port){_mainThread = SynchronizationContext.Current;IP = ip;Port = port;}public void Connect(Action success = null, Action error = null){Action<bool> onTrigger = (flag) =>{if (flag){PostMainThreadAction(success);PostMainThreadAction(OnConnectSuccess);}else{PostMainThreadAction(error);PostMainThreadAction(OnConnectError);}if (_connTimeoutTimer != null){_connTimeoutTimer.Stop();_connTimeoutTimer = null;}};try{_client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建套接字_client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, TIMEOUT_SEND);_client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, TIMEOUT_RECEIVE);IPAddress ipAddress = IPAddress.Parse(IP);//解析IP地址IPEndPoint ipEndpoint = new IPEndPoint(ipAddress, Port);IAsyncResult result = _client.BeginConnect(ipEndpoint, new AsyncCallback((iar) =>{try{Socket client = (Socket)iar.AsyncState;client.EndConnect(iar);_isConnect = true;// 开始发送心跳包_headTimer = new System.Timers.Timer(HEAD_OFFSET);_headTimer.AutoReset = true;_headTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){Send((UInt16)SocketEvent.sc_head);};_headTimer.Start();// 开始接收数据_receiveThread = new Thread(new ThreadStart(ReceiveEvent));_receiveThread.IsBackground = true;_receiveThread.Start();onTrigger(true);}catch (SocketException ex){onTrigger(false);}}), _client);//异步连接_connTimeoutTimer = new System.Timers.Timer(TIMEOUT_CONNECT);_connTimeoutTimer.AutoReset = false;_connTimeoutTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){onTrigger(false);};_connTimeoutTimer.Start();}catch (SocketException ex){onTrigger(false);// throw;}}/// <summary>/// 断线重连/// </summary>/// <param name="num"></param>public void ReConnect(int num = RECONN_MAX_SUM, int index = 0){_isReconnect = true;num--;index++;if (num < 0){onDisconnect();_isReconnect = false;return;}PostMainThreadAction<int>(OnReconnecting, index);Connect(() =>{PostMainThreadAction<int>(OnReConnectSuccess, index);_isReconnect = false;}, () =>{PostMainThreadAction<int>(OnReConnectError, index);ReConnect(num, index);});}public void Send(UInt16 e, byte[] buff = null, Action<SocketDataPack> onTrigger = null){buff = buff ?? new byte[] { };var dataPack = new SocketDataPack(e, buff);var data = dataPack.Buff;try{_client.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback((asyncSend) =>{Socket c = (Socket)asyncSend.AsyncState;c.EndSend(asyncSend);PostMainThreadAction<SocketDataPack>(onTrigger, dataPack);PostMainThreadAction<SocketDataPack>(OnSend, dataPack);}), _client);}catch (SocketException ex){onError(ex);}}/// <summary>/// 线程内接收数据的函数/// </summary>private void ReceiveEvent(){while (true){try{if (!_isConnect) break;if (_client.Available <= 0) continue;byte[] rbytes = new byte[8 * 1024];int len = _client.Receive(rbytes);if (len > 0){_dataBuffer.AddBuffer(rbytes, len); // 将收到的数据添加到缓存器中var dataPack = new SocketDataPack();if (_dataBuffer.TryUnpack(out dataPack)) // 尝试解包{if (dataPack.Type == (UInt16)SocketEvent.sc_kickout){// 服务端踢出onDisconnect();}else{// 收到消息PostMainThreadAction<SocketDataPack>(OnReceive, dataPack);}}}}catch (SocketException ex){onError(ex);// throw;}}}/// <summary>/// 业务逻辑 - 客户端主动断开/// </summary>public void DisConnect(){Send((UInt16)SocketEvent.sc_disconn);onDisconnect();}/// <summary>/// 缓存数据清理/// </summary>public void Close(){if (!_isConnect) return;_isConnect = false;if (_headTimer != null){_headTimer.Stop();_headTimer = null;}// if (_receiveThread != null)// {//     _receiveThread.Abort();//     _receiveThread = null;// }if (_connTimeoutTimer != null){_connTimeoutTimer.Stop();_connTimeoutTimer = null;}if (_client != null){_client.Close();_client = null;}}/// <summary>/// 错误回调/// </summary>/// <param name="e"></param>private void onError(SocketException ex){Close();PostMainThreadAction<SocketException>(OnError, ex);if (!_isReconnect){ReConnect();}}/// <summary>/// 断开回调/// </summary>private void onDisconnect(){Close();PostMainThreadAction(OnDisconnect);}/// <summary>/// 通知主线程回调/// </summary>private void PostMainThreadAction(Action action){_mainThread.Post(new SendOrPostCallback((o) =>{Action e = (Action)o.GetType().GetProperty("action").GetValue(o);if (e != null) e();}), new { action = action });}private void PostMainThreadAction<T>(Action<T> action, T arg1){_mainThread.Post(new SendOrPostCallback((o) =>{Action<T> e = (Action<T>)o.GetType().GetProperty("action").GetValue(o);T t1 = (T)o.GetType().GetProperty("arg1").GetValue(o);if (e != null) e(t1);}), new { action = action, arg1 = arg1 });}public void PostMainThreadAction<T1, T2>(Action<T1, T2> action, T1 arg1, T2 arg2){_mainThread.Post(new SendOrPostCallback((o) =>{Action<T1, T2> e = (Action<T1, T2>)o.GetType().GetProperty("action").GetValue(o);T1 t1 = (T1)o.GetType().GetProperty("arg1").GetValue(o);T2 t2 = (T2)o.GetType().GetProperty("arg2").GetValue(o);if (e != null) e(t1, t2);}), new { action = action, arg1 = arg1, arg2 = arg2 });}
}

我们依然先从成员变量开始说起：

    /// <summary>/// 主线程/// </summary>private SynchronizationContext _mainThread;public string IP;public int Port;private const int TIMEOUT_CONNECT = 3000;   // 连接超时时间 毫秒private const int TIMEOUT_SEND = 3000;  // 发送超时时间 毫秒private const int TIMEOUT_RECEIVE = 3000;   //接收超时时间 毫秒private const int HEAD_OFFSET = 2000; //心跳包发送间隔 毫秒private const int RECONN_MAX_SUM = 3;   //最大重连次数private Socket _client;private Thread _receiveThread;private System.Timers.Timer _connTimeoutTimer;private System.Timers.Timer _headTimer;private DataBuffer _dataBuffer = new DataBuffer();public event Action OnConnectSuccess;    // 连接成功回调public event Action OnConnectError;    // 连接失败回调public event Action OnDisconnect;  // 断开回调public event Action<SocketDataPack> OnReceive;  // 接收报文回调public event Action<SocketDataPack> OnSend;  // 发送报文回调public event Action<SocketException> OnError;   // 异常捕获回调public event Action<int> OnReConnectSuccess; // 重连成功回调public event Action<int> OnReConnectError; // 单次重连失败回调public event Action<int> OnReconnecting;  // 单次重连中回调private bool _isConnect = false;private bool _isReconnect = false;

依然是主线程的线程上下文，端口，IP，然后是连接超时的时间、发送超时时间、接收超时时间，都设置为3000ms（就是3s），然后是心跳包发送的最大间隔为2000ms，以及最大的重连次数为3。

然后是一个Socket类的实例client，一个接收线程，一个用于连接的计时器和一个心跳计时器，以及一个数据缓冲区。

然后是一系列event，注释里都有写明，我就不多赘述。

最后是两个bool变量表示是否连接以及是否重连。

    public SocketClient(string ip, int port){_mainThread = SynchronizationContext.Current;IP = ip;Port = port;}

有参构造：把线程上下文给到主线程，IP和端口都同步。

    public void Connect(Action success = null, Action error = null){Action<bool> onTrigger = (flag) =>{if (flag){PostMainThreadAction(success);PostMainThreadAction(OnConnectSuccess);}else{PostMainThreadAction(error);PostMainThreadAction(OnConnectError);}if (_connTimeoutTimer != null){_connTimeoutTimer.Stop();_connTimeoutTimer = null;}};try{_client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//创建套接字_client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.SendTimeout, TIMEOUT_SEND);_client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, TIMEOUT_RECEIVE);IPAddress ipAddress = IPAddress.Parse(IP);//解析IP地址IPEndPoint ipEndpoint = new IPEndPoint(ipAddress, Port);IAsyncResult result = _client.BeginConnect(ipEndpoint, new AsyncCallback((iar) =>{try{Socket client = (Socket)iar.AsyncState;client.EndConnect(iar);_isConnect = true;// 开始发送心跳包_headTimer = new System.Timers.Timer(HEAD_OFFSET);_headTimer.AutoReset = true;_headTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){Send((UInt16)SocketEvent.sc_head);};_headTimer.Start();// 开始接收数据_receiveThread = new Thread(new ThreadStart(ReceiveEvent));_receiveThread.IsBackground = true;_receiveThread.Start();onTrigger(true);}catch (SocketException ex){onTrigger(false);}}), _client);//异步连接_connTimeoutTimer = new System.Timers.Timer(TIMEOUT_CONNECT);_connTimeoutTimer.AutoReset = false;_connTimeoutTimer.Elapsed += delegate (object sender, ElapsedEventArgs args){onTrigger(false);};_connTimeoutTimer.Start();}catch (SocketException ex){onTrigger(false);// throw;}}

这是我们的连接函数，参数中包含了两个action，分别表示连接是否成功。

然后是一个名为onTrigger的接收参数类型为bool类型的Action委托，接收flag参数来决定回调函数以及计时器的处理。如果flag为true则在主线程中触发success委托和OnConnectSuccess委托，否则触发error委托和OnConnectError委托，此时如果存在连接超时计时器则暂停计时并清空。

为什么要清空计时器？

然后是一系列的Socket对象实例和设置，我们创建一个基于IPV4的TCP流式套接字对象，并设置他的发送消息超时阈值和接收消息超时阈值，最后解析得到源IP和目标IP。

接着是发起连接的函数，这里我们采用异步连接的方式，也就是APM模式（Asynchronous Programming Model，异步编程模型）:

其中涉及到的核心：IAsyncResult对象的概念：

我们将客户端的socket对象作为状态对象传入函数参数中,可以看到有一个从iar.AsyncState冲取出套接字的过程，然后客户端结束连接的异步操作。

为什么要在这里执行EndConnect呢？

后续就是一系列的连接成功后要处理的内容比如生成计时器，发送心跳包和生成接收消息的线程。当然，如果连接失败的话，我们就返回OnTrigger(false)。

后续是一个单次触发的连接超时计时器（AutoReset=false代表单次触发），触发后执行OnTrigger(false)。

/// <summary>
/// 断线重连
/// </summary>
/// <param name="num"></param>
public void ReConnect(int num = RECONN_MAX_SUM, int index = 0)
{_isReconnect = true;num--;index++;if (num < 0){onDisconnect();_isReconnect = false;return;}PostMainThreadAction<int>(OnReconnecting, index);Connect(() =>{PostMainThreadAction<int>(OnReConnectSuccess, index);_isReconnect = false;}, () =>{PostMainThreadAction<int>(OnReConnectError, index);ReConnect(num, index);});}

然后是我们重连的函数，我们接收的参数最大的重连次数和重连次数的序号。每次重连都更新isReconnect和最大重连次数和重连次数的序号，如果已经没有最大的重连次数我们就放弃尝试重连。通知主线程执行重连回调函数，然后返回Connect根据是否连接成功返回的两个回调函数。

    public void Send(UInt16 e, byte[] buff = null, Action<SocketDataPack> onTrigger = null){buff = buff ?? new byte[] { };var dataPack = new SocketDataPack(e, buff);var data = dataPack.Buff;try{_client.BeginSend(data, 0, data.Length, SocketFlags.None, new AsyncCallback((asyncSend) =>{Socket c = (Socket)asyncSend.AsyncState;c.EndSend(asyncSend);PostMainThreadAction<SocketDataPack>(onTrigger, dataPack);PostMainThreadAction<SocketDataPack>(OnSend, dataPack);}), _client);}catch (SocketException ex){onError(ex);}}

Send函数，上来有一个null的合并运算符：

我们将数据类型和数据封装成data，然后执行Socket的BeginSend和EndSend异步操作，并通知主线程执行OnTrigger回调和OnSend回调。

    /// <summary>/// 线程内接收数据的函数/// </summary>private void ReceiveEvent(){while (true){try{if (!_isConnect) break;if (_client.Available <= 0) continue;byte[] rbytes = new byte[8 * 1024];int len = _client.Receive(rbytes);if (len > 0){_dataBuffer.AddBuffer(rbytes, len); // 将收到的数据添加到缓存器中var dataPack = new SocketDataPack();if (_dataBuffer.TryUnpack(out dataPack)) // 尝试解包{if (dataPack.Type == (UInt16)SocketEvent.sc_kickout){// 服务端踢出onDisconnect();}else{// 收到消息PostMainThreadAction<SocketDataPack>(OnReceive, dataPack);}}}}catch (SocketException ex){onError(ex);// throw;}}}

接收消息的函数，我们利用while(true)来实时监听Socket数据流，检查连接状态以及socket是否有数据，这里使用了一个Available。

如果缓冲区无数据可读而依然执行Receive的话可能会导致CPU的空转：

有数据的话我们就去接收数据，生成一个新的数组进行数据的接收，接收到的数据我们丢到缓冲区中，并尝试解包，如果解包函数返回的类型是断开连接，意味着服务器主动要求客户端断开连接，这时候我们就会去执行断开连接，否则我们都会通知主线程来执行OnReceive回调。

/// <summary>
/// 业务逻辑 - 客户端主动断开
/// </summary>
public void DisConnect()
{Send((UInt16)SocketEvent.sc_disconn);onDisconnect();
}

主动断开连接的函数，我们会向服务器发送预定义好的断开连接的事件码，然后执行断开连接的委托。

/// <summary>
/// 缓存数据清理
/// </summary>
public void Close()
{if (!_isConnect) return;_isConnect = false;if (_headTimer != null){_headTimer.Stop();_headTimer = null;}// if (_receiveThread != null)// {//     _receiveThread.Abort();//     _receiveThread = null;// }if (_connTimeoutTimer != null){_connTimeoutTimer.Stop();_connTimeoutTimer = null;}if (_client != null){_client.Close();_client = null;}}

关闭客户端的操作就是将一系列连接状态和心跳包还有计数器和socket本身全部关闭。

    /// <summary>/// 错误回调/// </summary>/// <param name="e"></param>private void onError(SocketException ex){Close();PostMainThreadAction<SocketException>(OnError, ex);if (!_isReconnect){ReConnect();}}

错误时执行的回调函数，首先是执行关闭客户端，然后通知主线程执行报错的委托，同时自动尝试重连。

    /// <summary>/// 断开回调/// </summary>private void onDisconnect(){Close();PostMainThreadAction(OnDisconnect);}

断开连接的回调。

   /// <summary>/// 通知主线程回调/// </summary>private void PostMainThreadAction(Action action){_mainThread.Post(new SendOrPostCallback((o) =>{Action e = (Action)o.GetType().GetProperty("action").GetValue(o);if (e != null) e();}), new { action = action });}private void PostMainThreadAction<T>(Action<T> action, T arg1){_mainThread.Post(new SendOrPostCallback((o) =>{Action<T> e = (Action<T>)o.GetType().GetProperty("action").GetValue(o);T t1 = (T)o.GetType().GetProperty("arg1").GetValue(o);if (e != null) e(t1);}), new { action = action, arg1 = arg1 });}public void PostMainThreadAction<T1, T2>(Action<T1, T2> action, T1 arg1, T2 arg2){_mainThread.Post(new SendOrPostCallback((o) =>{Action<T1, T2> e = (Action<T1, T2>)o.GetType().GetProperty("action").GetValue(o);T1 t1 = (T1)o.GetType().GetProperty("arg1").GetValue(o);T2 t2 = (T2)o.GetType().GetProperty("arg2").GetValue(o);if (e != null) e(t1, t2);}), new { action = action, arg1 = arg1, arg2 = arg2 });}

通知主线程执行委托的函数，这里是三个参数不同的版本，这里的代码格式有些复杂：

       _mainThread.Post(new SendOrPostCallback((o) =>{Action e = (Action)o.GetType().GetProperty("action").GetValue(o);if (e != null) e();}), new { action = action });

中的(o) =>{...}是一个lambda表达式，表示接收参数为o的一个匿名函数，函数内部的内容是从o处获取运行时类型，从中获取运行时属性中名为“action”的属性，如果有的话获取其值并转换成Action类型给到e。在o处获取的action会赋值给我们新生成的名为action匿名变量，这一步的目的是：