Silverlight实用窍门系列:67.Silverlight下的Socket通讯
在Silverlight中进行通讯,只能使用4502-4534之间的端口进行数据传输,另外Silverlight客户端会自动向943端口的服务器端发送一个“<policy-file-request/>”的语句请求,然后服务器端943端口回发以下文件以许可Socket通讯。
<?xml version="1.0" encoding="utf-8" ?> <access-policy> <cross-domain-access> <policy> <allow-from> <domain uri="*"/> </allow-from> <grant-to> <socket-resource port="4502-4534" protocol="tcp"/> </grant-to> </policy> </cross-domain-access> </access-policy>
A.现在我们首先来看服务器端的代码,主要分为策略响应步骤和服务响应步骤。
策略步骤一:启动监听943端口是否有需要安全策略文件请求
策略步骤二:如果客户端请求是<policy-file-request/>,则将安全策略文件作为bytes发送给客户端
服务步骤一:启动服务器端,监听4525端口,是否有Socket对话请求
服务步骤二:如果有客户端请求的连接,则发送消息告知客户端
代码如下:
class Program { static void Main(string[] args) { //策略步骤一:启动监听943端口是否有需要安全策略文件请求 Thread access = new Thread(new ThreadStart(accessThread)); access.Start(); //服务步骤一:启动服务器端,监听4525端口,是否有Socket对话请求 Thread server = new Thread(new ThreadStart(ServerThread)); server.Start(); } //策略请求监听 static void accessThread() { //获取943端口监听的Socket服务端 Socket socket = GetSocketServer(943); while (true) { Socket new_access = socket.Accept(); string clientPolicyString = "<policy-file-request/>"; byte[] requestbytes = new byte[clientPolicyString.Length]; new_access.Receive(requestbytes); string requeststring = System.Text.Encoding.UTF8.GetString(requestbytes, 0, requestbytes.Length); if (requeststring == clientPolicyString) { //策略步骤二:如果客户端请求是<policy-file-request/>,则将安全策略文件作为bytes发送给客户端 byte[] accessbytes = GetPolicyToClient(); new_access.Send(accessbytes, accessbytes.Length, SocketFlags.None); new_access.Close(); } Thread.Sleep(100); } } static void ServerThread() { //获取4525端口监听的Socket服务端 Socket socket = GetSocketServer(4525); while (true) { Socket _socket = socket.Accept(); //服务步骤二:如果有客户端请求的连接,则发送消息告知客户端 byte[] b2 = new byte[1024]; _socket.Receive(b2); Console.WriteLine(Encoding.UTF8.GetString(b2).Replace("\0", "")); string recString = "我已经收到消息了"; _socket.Send(Encoding.UTF8.GetBytes(recString)); _socket.Close(); Thread.Sleep(100); } } //根据端口建立Socket服务器端 static Socket GetSocketServer(int serverPort) { Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); socket.Bind(new IPEndPoint(IPAddress.Any, serverPort)); socket.Listen(40); return socket; } //获取安全策略文件的byte[] static byte[] GetPolicyToClient() { string path = Environment.CurrentDirectory.Replace("\\bin\\Debug",""); FileStream fs = new FileStream(path+ @"\clientaccesspolicy.xml", FileMode.Open); int length = (int)fs.Length; byte[] bytes = new byte[length]; fs.Read(bytes, 0, length); fs.Close(); return bytes; } }
B.其次我们来看客户端操作,分为以下几个步骤:
客户端步骤一:发起服务器连接请求。
客户端步骤二:连接服务器成功,将需要发送的数据放入缓冲区中,然后异步向服务器发送消息请求
客户端步骤三:消息发送成功,此时设置一个新的缓冲区实例,并且发起异步接收服务器返回的消息
客户端步骤四:获取到服务器返回的消息,关闭Socket
客户端cs代码如下:
public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); } System.Net.Sockets.Socket socket; private void button1_Click(object sender, RoutedEventArgs e) { byte[] userbytes = Encoding.UTF8.GetBytes(this.tbInput.Text); socket = new System.Net.Sockets.Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); SocketAsyncEventArgs socketArgs = new SocketAsyncEventArgs(); socketArgs.RemoteEndPoint = new DnsEndPoint("127.0.0.1", 4525); //将需要发送的内容转为byte[],保存到UserToken属性中 socketArgs.UserToken = userbytes; socketArgs.Completed += new EventHandler<SocketAsyncEventArgs>(socketArgs_Completed); //客户端步骤一:发起服务器连接请求。 socket.ConnectAsync(socketArgs); } //每发生一个Socket操作都讲激活此方法,操作包括(Connect/Send/Receive/None) void socketArgs_Completed(object sender, SocketAsyncEventArgs e) { if (e.LastOperation == SocketAsyncOperation.Connect) { //客户端步骤二:连接服务器成功,将需要发送的数据放入缓冲区中,然后异步向服务器发送消息请求 byte[] userbytes = (byte[])e.UserToken; e.SetBuffer(userbytes, 0, userbytes.Length); socket.SendAsync(e); } else if (e.LastOperation == SocketAsyncOperation.Send) { //客户端步骤三:消息发送成功,此时设置一个新的缓冲区实例,并且发起异步接收服务器返回的消息 byte[] userbytes = new byte[1024]; e.SetBuffer(userbytes, 0, userbytes.Length); socket.ReceiveAsync(e); } else if (e.LastOperation == SocketAsyncOperation.Receive) { //客户端步骤四:获取到服务器返回的消息,关闭Socket string RecevieStr = Encoding.UTF8.GetString(e.Buffer, 0, e.Buffer.Length).Replace("\0", ""); //因为是异步Socket请求,所以需要使用UI线程更新lbShowMessage的显示效果 this.lbShowMessage.Dispatcher.BeginInvoke(new DoThingDele(DoThing), RecevieStr); socket.Close(); } } //更新UI public void DoThing(string arg) { this.lbShowMessage.Content = this.lbShowMessage.Content + "->" + arg; } //声明的一个DoThing方法委托 public delegate void DoThingDele(string arg); }
客户端Xaml前台代码如下:
<Grid x:Name="LayoutRoot" Background="White" ShowGridLines="True"> <TextBox Height="23" HorizontalAlignment="Left" Margin="20,20,0,0" Name="tbInput" VerticalAlignment="Top" Width="243" /> <Button Content="发 送" Height="23" HorizontalAlignment="Left" Margin="279,20,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" /> <sdk:Label Height="28" HorizontalAlignment="Left" Margin="20,57,0,0" Name="lbShowMessage" VerticalAlignment="Top" Width="358" /> </Grid>
最后效果如下,如需源码请点击 SLSocket.zip 下载,本文演示的是最简单通讯效果: