C#基于Socket的简单聊天室实践
序:实现一个基于Socket的简易的聊天室,实现的思路如下:
程序的结构:多个客户端+一个服务端,客户端都是向服务端发送消息,然后服务端转发给所有的客户端,这样形成一个简单的聊天室功能。
实现的细节:服务端启动一个监听套接字。每一个客户端连接到服务端,都是开启了一个线程,线程函数是封装了通信套接字,来实现与客户端的通信。多个客户端连接时产生的通信套接字用一个静态的Dictionary保存。具体的实现可以参考代码及其注释。
术语理解:
套接字Socket:源于Unix,为了解决传输层网络编程的问题,Unix提供了类似于文件操作的方式来完成网络编程。要实现不同的主机,不同的程序之间进行通信,必须有相应的协议,这个协议便是TCP/IP协议。Socket是负责传输层的,基于TCP的。不同的主机之间可以通过IP地址识别,但是不同的主机上有众多的程序或者说是进程。一台主机上的进程要跟另一台主机上的进程通信,必须有双方能够唯一识别的标志。就像人的身份证号,手机号等。这里出现了EndPoint(端点)的概念。
EndPoint(端点):由IP地址和端口号构成,端口对应进程。这两个组合起来可以唯一的标识网络中某台主机上的某一个进程。这样就有一个唯一的身份标识,后面可以进行通信了。
每一个Socket需要绑定到端点进行通信。
Socket的常见的通信数据类型有两种:数据报(SOCK_DGRAM)和数据流(SOCK_STREAM),使用的网络协议TCP或UDP等等。
关于TCP
TCP是一种面向连接的,可靠的,基于字节流的传输层通信协议。
TCP的工作过程包括三个方面:
(1)建立连接:这个过程称为三次握手。
第一次:客户端发送SYN包(SEQ=x)到服务器,并进入SYN_SEND状态,等待服务器确认。
第二次:服务器收到SYN包,必须确认客户端的SYN(ACK=x+1),同时自己发送一个SYN包(SEQ=y),即SYN+ACK包,此时服务器进入SYN_RECV状态
第三次:客户端收到服务器发来的SYN+ACK包,向服务器发送确认包ACK(ACK=y+1),此包发送完毕,客户端和服务端进入Established状态。至此三次握手完成。
(2)传输数据:一旦通信双方建立了TCP连接,就可以相互发送数据。
(3)终止连接:关闭连接,需要四次握手,这个是由于TCP的半关闭造成的。
这个网上有很多资料,大家可以查阅下。
关于.NET里面的Socket
在.NET里面的System.Net.Sockets命名空间下提供了对Socket的操作。并且专门封装了TcpClient和TcpListener两个类来简化操作。我这里是直接用Socket实现的。这里分为这样几个步骤:
在服务端:
(1)声明一个套接字(称为监听套接字)Socket serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
(2)声明一个端点(EndPoint)上面提到过Socket需要跟它绑定才能通信。IPEndPoint endPoint = new IPEndPoint(IPAddress.Loopback, 8080);
(3)设置监听队列serverSocket.Listen(100);
(4)通过Accept()方法来获取一个通信套接字(当有客户端连接时),这个方法会阻塞线程,避免界面卡死的现象,启动一个线程,把这个Accept()放在线程函数里面。
在客户端:
(1)声明一个套接字,通过connect()向服务器发起连接。
(2)通过Receive方法获取服务器发来的消息(这里同样启用一个线程,通过while循环来实时监听服务器端发送的消息)
注意:数据是以字节流(Byte[])的形式传递的,我会使用Encoding.UTF8.GetString()方法来获取为字符串。都是通过Send()来向彼此发送消息。
聊天室开始
我这里使用的是WPF来创建的Server和Client端。
首先看下服务端,我创建一个ChatServer的WPF项目,包含一个ChatServer.xaml:
<Window x:Class="ChatWPFServer.ChatServer" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="ChatServer" Height="350" Width="525" Closed="Window_Closed"> <Grid> <Button Content="启动" Name="btnStart" HorizontalAlignment="Left" Margin="28,29,0,0" VerticalAlignment="Top" Width="105" Height="39" Click="btnStart_Click" /> <Button Content="停止" Name="btnStop" HorizontalAlignment="Left" Margin="193,29,0,0" VerticalAlignment="Top" Width="108" Height="39" Click="btnStop_Click" /> <TextBox Name="txtMsg" HorizontalAlignment="Left" Height="200" AcceptsReturn="True" Margin="28,98,0,0" IsReadOnly="True" TextWrapping="Wrap" VerticalScrollBarVisibility="Auto" Text="" VerticalAlignment="Top" Width="460"/> </Grid> </Window>
后台代码:
namespace ChatWPFServer { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class ChatServer : Window { public ChatServer() { InitializeComponent(); } //保存多个客户端的通信套接字 public static Dictionary<String, Socket> clientList = null; //声明一个监听套接字 Socket serverSocket = null; //设置一个监听标记 Boolean isListen = true; private void btnStart_Click(object sender, RoutedEventArgs e) { if (serverSocket == null) { isListen = true; clientList = new Dictionary<string, Socket>(); serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);//实例监听套接字 IPEndPoint endPoint = new IPEndPoint(IPAddress.Loopback, 8080);//端点 serverSocket.Bind(endPoint);//绑定 serverSocket.Listen(100);//设置最大连接数 Thread th = new Thread(StartListen); th.IsBackground = true; th.Start(); txtMsg.Dispatcher.BeginInvoke(new Action(() => { txtMsg.Text += "服务启动... "; })); } } //线程函数,封装一个建立连接的通信套接字 private void StartListen() { Socket clientSocket = default(Socket); try { while (isListen) { clientSocket = serverSocket.Accept();//这个方法返回一个通信套接字 Byte[] bytesFrom = new Byte[4096]; String dataFromClient = null; Int32 len = clientSocket.Receive(bytesFrom);//获取客户端发来的信息 if (len > 0) { dataFromClient = Encoding.UTF8.GetString(bytesFrom, 0, len); Int32 sublen = dataFromClient.LastIndexOf("$"); if (sublen > -1) { dataFromClient = dataFromClient.Substring(0, sublen); if (!clientList.ContainsKey(dataFromClient)) { clientList.Add(dataFromClient, clientSocket); BroadCast.PushMessage(dataFromClient + " Joined ", dataFromClient, false, clientList); HandleClient client = new HandleClient(); client.StartClient(clientSocket, dataFromClient, clientList); } else { clientSocket.Send(Encoding.UTF8.GetBytes("#" + dataFromClient + "#")); } } } } } catch (Exception ex) { if (clientSocket != null && !clientSocket.Connected) { clientSocket.Close(); clientSocket = null; } isListen = false; File.AppendAllText("E:\Exception.txt", ex.ToString()); } } private void btnStop_Click(object sender, RoutedEventArgs e) { if (serverSocket != null) { foreach (var socket in clientList.Values) { socket.Close(); } clientList.Clear(); serverSocket.Close(); serverSocket = null; isListen = false; txtMsg.Text += "服务停止 "; } } private void Window_Closed(object sender, EventArgs e) { isListen = false; BroadCast.PushMessage("Server has closed", "", false, clientList); clientList.Clear(); serverSocket.Close(); serverSocket = null; } } //这里专门负责接收客户端发来的消息,并且转发给所有的客户端 public class HandleClient { Socket clientSocket; String clNo; Dictionary<String, Socket> clientList = new Dictionary<string, Socket>(); public void StartClient(Socket inClientSocket, String clientNo, Dictionary<String, Socket> cList) { clientSocket = inClientSocket; clNo = clientNo; clientList = cList; Thread th = new Thread(Chat); th.IsBackground = true; th.Start(); } private void Chat() { Byte[] bytesFromClient = new Byte[4096]; String dataFromClient; String msgTemp = null; Byte[] bytesSend = new Byte[4096]; Boolean isListen = true; try { while (isListen) { Int32 len = clientSocket.Receive(bytesFromClient); dataFromClient = Encoding.UTF8.GetString(bytesFromClient, 0, len); if (!String.IsNullOrWhiteSpace(dataFromClient)) { dataFromClient = dataFromClient.Substring(0, dataFromClient.LastIndexOf("$")); if (!String.IsNullOrWhiteSpace(dataFromClient)) { BroadCast.PushMessage(dataFromClient, clNo, true, clientList); msgTemp = clNo + ": " + dataFromClient + " " + DateTime.Now.ToString(); File.AppendAllText("E:\MessageRecords.txt", msgTemp + " ", Encoding.UTF8); } else { clientList.Remove(clNo); clientSocket.Close(); clientSocket = null; isListen = false; } } } } catch (SocketException ex) { isListen = false; clientList.Remove(clNo); clientSocket.Close(); clientSocket = null; File.AppendAllText("E:\Exception.txt", ex.ToString()); } } } //向所有的客户端发送消息 public class BroadCast { public static void PushMessage(String msg, String uName, Boolean flag, Dictionary<String, Socket> clientList) { foreach (var item in clientList) { Socket brdcastSocket = (Socket)item.Value; String msgTemp = null; Byte[] castBytes = new Byte[4096]; if (flag == true) { msgTemp = uName + ": " + msg + " " + DateTime.Now.ToString(); castBytes = Encoding.UTF8.GetBytes(msgTemp); } else { msgTemp = msg + " " + DateTime.Now.ToString(); castBytes = Encoding.UTF8.GetBytes(msgTemp); } try { brdcastSocket.Send(castBytes); } catch (Exception ex) { brdcastSocket.Close(); brdcastSocket = null; File.AppendAllText("E:\Exception.txt", ex.ToString()); continue; } } } } }
网络编程的环境比较复杂,里面很多地方进行了异常处理和判断。这是通过我实际的调试不断完善的,有的bug甚至是放到了真实的服务器上运行了几个小时以后发现的。所以异常处理最后是记录下来,这样能够便于发现问题。
客户端xaml:
<Window x:Class="ChatClient.ChatRoom" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="ChatRoom" Height="550" Width="500" Closed="Window_Closed_1" Activated="Window_Activated_1" WindowStartupLocation="CenterScreen"> <Window.Resources> <RoutedUICommand x:Key="SendMessageShortcutKey" Text="Send Message Shortcut Key"></RoutedUICommand> </Window.Resources> <Window.InputBindings> <KeyBinding Gesture="Ctrl+Enter" Command="{StaticResource SendMessageShortcutKey}"></KeyBinding> </Window.InputBindings> <Window.CommandBindings> <CommandBinding Command="{StaticResource SendMessageShortcutKey}" CanExecute="CommandBinding_SendMessage_CanExecute" Executed="CommandBinding_SendMessage_Executed"> </CommandBinding> </Window.CommandBindings> <Grid> <Grid.RowDefinitions> <RowDefinition Height="50"></RowDefinition> <RowDefinition Height="250"></RowDefinition> <RowDefinition Height="150"></RowDefinition> <RowDefinition Height="80"></RowDefinition> </Grid.RowDefinitions> <StackPanel Grid.Row="0" Orientation="Horizontal"> <Label Name="lbMsg" Content="设置你的用户名:" Margin="10,10"></Label> <TextBox Name="txtName" Width="200" Height="30" FontSize="16"></TextBox> <Button Name="btnConnect" Content="连接服务器" Width="100" Height="30" Margin="15,8" Click="btnConnect_Click"></Button> </StackPanel> <TextBox Grid.Row="1" Name="txtReceiveMsg" Margin="10" BorderBrush="DarkGreen" TextWrapping="Wrap" VerticalScrollBarVisibility="Auto" Foreground="DarkBlue" IsReadOnly="True"></TextBox> <TextBox Grid.Row="2" Name="txtSendMsg" Margin="10,0" AcceptsReturn="True" BorderBrush="DarkBlue" TextWrapping="Wrap" VerticalScrollBarVisibility="Auto"></TextBox> <Button Grid.Row="3" Name="btnSend" Content="发送(Ctrl+Enter)" Width="100" Height="30" Click="btnSend_Click"></Button> </Grid> </Window>
后台代码:
namespace ChatClient { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class ChatRoom : Window { public ChatRoom() { InitializeComponent(); } Socket clientSocket = null; static Boolean isListen = true; private void btnSend_Click(object sender, RoutedEventArgs e) { SendMessage(); } private void SendMessage() { if (String.IsNullOrWhiteSpace(txtSendMsg.Text.Trim())) { MessageBox.Show("发送内容不能为空哦~"); return; } if (clientSocket != null && clientSocket.Connected) { Byte[] bytesSend = Encoding.UTF8.GetBytes(txtSendMsg.Text + "$"); clientSocket.Send(bytesSend); txtSendMsg.Text = ""; } else { MessageBox.Show("未连接服务器或者服务器已停止,请联系管理员~"); return; } } /// <summary> /// 每一个连接的客户端必须设置一个唯一的用户名,在服务端是把用户名和通信套接字 /// 保存在Dictionary<UserName,ClientSocket>. /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void btnConnect_Click(object sender, RoutedEventArgs e) { if (String.IsNullOrWhiteSpace(txtName.Text.Trim())) { MessageBox.Show("还是设置一个用户名吧,这样别人才能认识你哦~"); return; } if (clientSocket == null) { try { clientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); clientSocket.BeginConnect(IPAddress.Loopback, 8080, (args) => { if (args.IsCompleted) { Byte[] bytesSend = new Byte[4096]; txtName.Dispatcher.BeginInvoke(new Action(() => { bytesSend = Encoding.UTF8.GetBytes(txtName.Text.Trim() + "$"); if (clientSocket != null && clientSocket.Connected) { clientSocket.Send(bytesSend); txtName.IsEnabled = false; txtSendMsg.Focus(); Thread th = new Thread(DataFromServer); th.IsBackground = true; th.Start(); } else { MessageBox.Show("服务器已经关闭"); } })); } }, null); } catch (SocketException ex) { MessageBox.Show(ex.ToString()); } } else { MessageBox.Show("You has already connected with Server"); } } private void ShowMsg(String msg) { txtReceiveMsg.Dispatcher.BeginInvoke(new Action(() => { txtReceiveMsg.Text += Environment.NewLine + msg; txtReceiveMsg.ScrollToEnd(); })); } //获取服务端的消息 private void DataFromServer() { ShowMsg("Connected to the Chat Server..."); isListen = true; try { while (isListen) { Byte[] bytesFrom = new Byte[4096]; Int32 len = clientSocket.Receive(bytesFrom); String dataFromClient = Encoding.UTF8.GetString(bytesFrom, 0, len); if (dataFromClient.StartsWith("#") && dataFromClient.EndsWith("#")) { String userName = dataFromClient.Substring(1, dataFromClient.Length - 2); this.Dispatcher.BeginInvoke(new Action(() => { MessageBox.Show("用户名:[" + userName + "]已经存在,请尝试其它用户名"); })); isListen = false; } else { ShowMsg(dataFromClient); } } } catch (SocketException ex) { isListen = false; if (clientSocket != null && clientSocket.Connected) { //我没有在客户端关闭连接而是向服务端发送一个消息,在服务器端关闭,这样主要 //为了异常的处理放到服务端。客户端关闭会抛异常,服务端也会抛异常。 clientSocket.Send(Encoding.UTF8.GetBytes("$")); MessageBox.Show(ex.ToString()); } } } //这是定义了一个发送的快捷键,WPF的知识 private void CommandBinding_SendMessage_CanExecute(object sender, CanExecuteRoutedEventArgs e) { if (String.IsNullOrWhiteSpace(txtSendMsg.Text.Trim())) { e.CanExecute = false; } else { e.CanExecute = true; } } private void CommandBinding_SendMessage_Executed(object sender, ExecutedRoutedEventArgs e) { SendMessage(); } private void Window_Activated_1(object sender, EventArgs e) { txtSendMsg.Focus(); } private void Window_Closed_1(object sender, EventArgs e) { if (clientSocket != null && clientSocket.Connected) { clientSocket.Send(Encoding.UTF8.GetBytes("$")); } } } }
好了,到这里告一段落了,一个简单的不能再简单的聊天室就完成了。这里还是有很多细节的处理,我不一定处理的很到位,如果你发现了,请留言告诉我。
截个图,看下运行的效果吧!
出处:http://www.cnblogs.com/mszhangxuefei/
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