Question

我基本上尝试从这里重现Socket示例：http://www.silverlightshow.net/items/Sockets-and-their-implementation-in-SL2-Beta-1-including-a-chat-like-example.aspx 我只在客户端做了一点改动，即

 String safeHost = "127.0.0.1";
            int port = 4509;

然后我收到了这个权限错误？知道为什么吗？

Silverlight应用程序中的未处理错误尝试以其访问权限禁止的方式访问套接字。

Answer 1

我相信套接字安全检查的工作方式，您需要使用应用程序使用的相同url字符串。为了确保我使用正确的字符串我一直用它来构建我的DNSEndPoint：

int Port = 4509;
DnsEndPoint ep = new DnsEndPoint(Application.Current.Host.Source.DnsSafeHost, Port, AddressFamily.InterNetwork);
Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
sock.NoDelay = true;
SocketAsyncEventArgs ea = new SocketAsyncEventArgs{RemoteEndPoint  = ep};
//set up completed event handler et al.
sock.ConnectAsync(ea);

我在类似的聊天应用程序中使用了这个确切的代码。通过使用Application.Current.Host.Source.DnsSafeHost属性，您可以确保使用相同的Dns名称来访问具有浏览器用于HttpRequests的套接字的服务器。

您还在端口943上提供访问策略文件，这是Silverlight中套接字支持的另一个要求。

修改

要确认您正在为策略文件提供服务，您可以执行许多操作。

安装Fiddler，您可以使用它来调试命中服务器的所有http流量，您应该能够看到对策略文件的请求。
动态提供策略文件，然后在服务器应用程序中设置断点以确认它正在提供服务。这就是我所做的。

这是我用来提供策略文件的代码：

public abstract class Server
{
    protected Socket Listener { get; set; }
    protected int Port { get; private set; }
    protected int Backlog { get; private set; }
    protected bool isStopped { get; set; }
    protected SocketAsyncEventArgs AcceptArgs {get;set;}

    public Server(int port)
    {
        AcceptArgs = new SocketAsyncEventArgs();
        AcceptArgs.Completed += new EventHandler<SocketAsyncEventArgs>(Accept_Completed);
        isStopped = true;
        Port = port;
        Backlog = 100;
    }


    public Server(int port, int backlog)
    {
        isStopped = true;
        Port = port;
        Backlog = backlog;
    }

    public void Start()
    {
        isStopped = false;

        Listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        IPEndPoint ep = new IPEndPoint(IPAddress.Any, Port);
        Listener.ExclusiveAddressUse = true;
        Listener.Bind(ep);
        //Console.WriteLine("Listening on " + Port);
        Listener.Listen(Backlog);

        Listener.AcceptAsync(AcceptArgs);
    }

    void Accept_Completed(object sender, SocketAsyncEventArgs e)
    {
        if (isStopped) return;
        Socket client = e.AcceptSocket;
        //Console.WriteLine("Accepted Connection From: " + client.RemoteEndPoint.ToString());
        e.AcceptSocket = null;
        Listener.AcceptAsync(AcceptArgs);
        HandleClient(client);
    }

    public virtual void Stop()
    {
        if (isStopped) throw new InvalidOperationException("Server already Stopped!");
        isStopped = true;
        try
        {
            Listener.Shutdown(SocketShutdown.Both);
            Listener.Close();
        }
        catch (Exception)
        {
        }
    }

    protected abstract void HandleClient(Socket Client);
}
public class PolicyServer : Server
{
    public const String policyStr = @"<?xml version=""1.0"" encoding=""utf-8"" ?>
                                        <access-policy>
                                            <cross-domain-access>
                                                <policy>
                                                    <allow-from>
                                                        <domain uri=""*"" />
                                                    </allow-from>
                                                    <grant-to>
                                                        <socket-resource port=""4530"" protocol=""tcp"" />
                                                    </grant-to>
                                                </policy>
                                            </cross-domain-access>
                                        </access-policy>";
    private byte[] policy = Encoding.ASCII.GetBytes(policyStr);
    private static string policyRequestString = "<policy-file-request/>";

    public PolicyServer(): base(943)
    {
    }

    protected override void HandleClient(Socket socket)
    {
        TcpClient client = new TcpClient { Client = socket };
        Stream s = client.GetStream();
        byte[] buffer = new byte[policyRequestString.Length];
        client.ReceiveTimeout = 5000;
        s.Read(buffer, 0, buffer.Length);//read in the request string, but don't do anything with it
                                                     //you could confirm that it is equal to the policyRequestString
        s.Write(policy, 0, policy.Length);
        s.Flush();

        socket.Shutdown(SocketShutdown.Both);
        socket.Close(1);
        client.Close();
    }
}

然后使用它：

PolicyServer ps = new PolicyServer();
ps.Start();
//then when shutting down
ps.Stop();

我在运行Chat Server组件其余部分的同一进程中托管了这个“服务器”。在HandleClient中设置断点以确认它是否正在接收请求。

Silverlight套接字：Silverlight应用程序中的未处理错误尝试以其访问权限禁止的方式访问套接字

1 个答案: