客户端封装整体框架
客户端编程基于阻塞同步模式，只有数据正常发送或接收才返回，如果发生错误则抛出异常，基于TcpClient进行封装，主要类结构如下图：
TcpClient：NET系统封装，实现了底层Socket操作，提供了阻塞和非阻塞调用；
OutgoingDataAssembler m_outgoingDataAssembler：协议组装器，用来组装往外发送的命令，主要用于组装协议格式；
DynamicBufferManager m_sendBuffer：用于把命令和数据同时写入到缓存中，调用一次发送，这样服务器就只会产生一次IOCP回调，可以提高性能；
IncomingDataParser m_incomingDataParser：收到数据的解析器，用于解析返回的内容，主要是解析文本格式；
protected DynamicBufferManager m_recvBuffer：接收数据的缓存，数据存到缓存中后，可以解析命令和数据；
TcpClient说明，阻塞和非阻塞
TcpClient封装了NET的底层Socket操作，基于TCP协议，，提供了阻塞和非阻塞模式调用，具体是设置m_tcpClient.Client.Blocking = true表示使用阻塞模式，反之则使用非阻塞模式。阻塞模式表示接收完指定长度的数据才返回，非阻塞模式表示收到一点数据就返回。
如我们调用m_tcpClient.Client.Receive(m_recvBuffer.Buffer, sizeof(int), packetLength, SocketFlags.None)，假设传入的长度为1024，阻塞模式一点要等到数据达到1024长度才返回，否则一直等待Socket超时或者链路断了，非阻塞模式则不同，加入收到8字节了，则返回调用者，调用者使用循环继续接受1024-8=1016的数据。
发送命令
发送数据和服务端相同，主要是对数据进行组包，然后调用发送函数发送，具体代码如下：
public void SendCommand(byte[] buffer, int offset, int count){string commandText = m_outgoingDataAssembler.GetProtocolText();byte[] bufferUTF8 = Encoding.UTF8.GetBytes(commandText);int totalLength = sizeof(int) + bufferUTF8.Length + count; //获取总大小m_sendBuffer.Clear();m_sendBuffer.WriteInt(totalLength, false); //写入总大小m_sendBuffer.WriteInt(bufferUTF8.Length, false); //写入命令大小m_sendBuffer.WriteBuffer(bufferUTF8); //写入命令内容m_sendBuffer.WriteBuffer(buffer, offset, count); //写入二进制数据m_tcpClient.Client.Send(m_sendBuffer.Buffer, 0, m_sendBuffer.DataCount, SocketFlags.None);}
接收命令
接收命令和发送相反，先接收长度，然后接收内容，然后对数据进行解包，具体代码如下：
public bool RecvCommand(out byte[] buffer, out int offset, out int size){m_recvBuffer.Clear();m_tcpClient.Client.Receive(m_recvBuffer.Buffer, sizeof(int), SocketFlags.None);int packetLength = BitConverter.ToInt32(m_recvBuffer.Buffer, 0); //获取包长度if (NetByteOrder)packetLength = System.Net.IPAddress.NetworkToHostOrder(packetLength); //把网络字节顺序转为本地字节顺序m_recvBuffer.SetBufferSize(sizeof(int) + packetLength); //保证接收有足够的空间m_tcpClient.Client.Receive(m_recvBuffer.Buffer, sizeof(int), packetLength, SocketFlags.None);int commandLen = BitConverter.ToInt32(m_recvBuffer.Buffer, sizeof(int)); //取出命令长度string tmpStr = Encoding.UTF8.GetString(m_recvBuffer.Buffer, sizeof(int) + sizeof(int), commandLen);if (!m_incomingDataParser.DecodeProtocolText(tmpStr)) //解析命令{buffer = null;offset = 0;size = 0;return false;}else{buffer = m_recvBuffer.Buffer;offset = commandLen + sizeof(int) + sizeof(int);size = packetLength – offset;return true;}}
命令交互
封装了底层Socket操作和协议解析后，实现一个命令交互如登录代码如下：
public bool DoLogin(string userName, string password){try{m_outgoingDataAssembler.Clear();m_outgoingDataAssembler.AddRequest();m_outgoingDataAssembler.AddCommand(AsyncSocketServer.ProtocolKey.Login);m_outgoingDataAssembler.AddValue(AsyncSocketServer.ProtocolKey.UserName, userName);m_outgoingDataAssembler.AddValue(AsyncSocketServer.ProtocolKey.Password, AsyncSocketServer.BasicFunc.MD5String(password));SendCommand();bool bSuccess = RecvCommand();if (bSuccess){bSuccess = CheckErrorCode();if (bSuccess){m_userName = userName;m_password = password;}return bSuccess;}elsereturn false;}catch (Exception E){//记录日志m_errorString = E.Message;return false;}}
上传协议
上传协议主要分为三个命令，第一个是Upload，向服务器请求上传的文件，如果服务器有相同的文件，则返回是否传完，如果未传完，返回需要续传的文件位置，然后客户端则从上一个位置开始传输，传输数据服务器只接收，不应答，客户端传输完后，发完成（EOF）命令。因此三个命令封装代码如下：
public bool DoUpload(string dirName, string fileName, ref long fileSize){bool bConnect = ReConnectAndLogin(); //检测连接是否还在，如果断开则重连并登录if (!bConnect)return bConnect;try{m_outgoingDataAssembler.Clear();m_outgoingDataAssembler.AddRequest();m_outgoingDataAssembler.AddCommand(AsyncSocketServer.ProtocolKey.Upload);m_outgoingDataAssembler.AddValue(AsyncSocketServer.ProtocolKey.DirName, dirName);m_outgoingDataAssembler.AddValue(AsyncSocketServer.ProtocolKey.FileName, fileName);SendCommand();bool bSuccess = RecvCommand();if (bSuccess){bSuccess = CheckErrorCode();if (bSuccess){bSuccess = m_incomingDataParser.GetValue(AsyncSocketServer.ProtocolKey.FileSize, ref fileSize);}return bSuccess;}elsereturn false;}catch (Exception E){//记录日志m_errorString = E.Message;return false;}}public bool DoData(byte[] buffer, int offset, int count){try{m_outgoingDataAssembler.Clear();m_outgoingDataAssembler.AddRequest();m_outgoingDataAssembler.AddCommand(AsyncSocketServer.ProtocolKey.Data);SendCommand(buffer, offset, count);return true;}catch (Exception E){//记录日志m_errorString = E.Message;return false;}}public bool DoEof(Int64 fileSize){try{m_outgoingDataAssembler.Clear();m_outgoingDataAssembler.AddRequest();m_outgoingDataAssembler.AddCommand(AsyncSocketServer.ProtocolKey.Eof);SendCommand();bool bSuccess = RecvCommand();if (bSuccess)return CheckErrorCode();elsereturn false;}catch (Exception E){//记录日志m_errorString = E.Message;return false;}}调用过程：protected static bool SendFile(string fileName, ClientUploadSocket uploadSocket){FileStream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.ReadWrite);try{try{long fileSize = 0;if (!uploadSocket.DoUpload("", Path.GetFileName(fileName), ref fileSize))throw new Exception(uploadSocket.ErrorString);fileStream.Position = fileSize;byte[] readBuffer = new byte[PacketSize];while (fileStream.Position < fileStream.Length){int count = fileStream.Read(readBuffer, 0, PacketSize);if (!uploadSocket.DoData(readBuffer, 0, count))throw new Exception(uploadSocket.ErrorString);}if (!uploadSocket.DoEof(fileStream.Length))throw new Exception(uploadSocket.ErrorString);return true;}catch (Exception E){Console.WriteLine("Upload File Error: " + E.Message);return false;}}finally{fileStream.Close();}}DEMO下载地址：免责声明：此代码只是为了演示C#完成端口编程，仅用于学习和研究，切勿用于商业用途。水平有限，C#也属于初学，错误在所难免，欢迎指正和指导。邮箱地址：fansheng_hx@163.com。
其实只要你愿意，一切都可以变得很容易。
