Websocket成功握手，但无法正确发送和接收消息（C#服务器）

Question

Websocket成功握手，但无法正确发送和接收消息（C#服务器）

4

早上我花了很长时间才解决了握手问题，但现在我卡在了发送和接收消息的过程中。我已经搜索了很多答案，但都没有找到合适的解决方法，所以我想在这里寻求帮助 :/

目前我的客户端非常简单：

function testWebSocket() {
    if (!window.WebSocket) {
        alert('WebSockets are NOT supported by your browser.');
        return;
    }

    try {
        var ws = new WebSocket('ws://localhost:8181/websession');
        ws.onopen = function () {
            alert('Handshake successfully established. Ready for data...');
        };

        ws.onmessage = function (e) {
            alert('Got WebSockets message: ' + e.data);
        }

        ws.onclose = function () {
            alert('Connection closed.');
        };
    }
    catch (e) {
        alert(e);
    }
}

是的，我在这个项目中借鉴了很多代码......我只是想用一个简单的“聊天应用程序”来实现概念验证

我的服务器主要由两个类组成，即SocketServer.cs和SocketClient.cs

它们如下：

SocketServer.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.IO;

namespace WebSocketServer.Entities
{
    class SocketServer
    {
        public static Form1 parentForm;
        TcpListener socketServer;
        public static List<SocketClient> ClientList = new List<SocketClient>();


        public SocketServer(Form1 pForm)
        {

            parentForm = pForm;
            parentForm.ApplyText("Socket Class Initiated\r\n");
            socketServer = new TcpListener(IPAddress.Any, 8181);
            // tell the console that it's started
            parentForm.ApplyText("Socket Server Started\r\n");

            // create continuous loops to listen for new connections
            // start the listener
            socketServer.Start();
            while (true)
            {
                // check for any incoming pending connections
                // create new socket client for new connection
                TcpClient socketConnection = socketServer.AcceptTcpClient();
                DateTime now = DateTime.Now;
                //write message to console to indicate new connection
                parentForm.ApplyText("New Client Connected - " + now.ToString("MM/dd/yyyy h:mm:ss tt") + "\r\n");
                // create new client object for this connection
                SocketClient socketClient = new SocketClient(socketConnection, parentForm);
            }
        }

        public static void CloseClient(SocketClient whichClient)
        {
            ClientList.Remove(whichClient);
            whichClient.Client.Close();
            // dispose of the client object
            whichClient.Dispose();
            whichClient = null;
            parentForm.ApplyText("Client Disconnected\r\n");
        }



        public static void SendTextToClient(SocketClient sc, string text)
        {
            StreamWriter writer = new StreamWriter(sc.Client.GetStream());
            // check if client is still connected, then send the text string
            try
            {
                if (sc.Client.Connected)
                {
                    writer.WriteLine(text);
                    writer.Flush();
                    writer = null;
                }
            }
            catch
            {
                CloseClient(sc);
            }

        }


        public static void SendBroadcast(string text)
        {
            StreamWriter writer;
            // loop through the array and send text to all clients
            foreach (SocketClient client in ClientList)
            {
                if (client.Client.Connected)
                {
                    try
                    {
                        writer = new StreamWriter(client.Client.GetStream());
                        writer.WriteLine(text);
                        writer.Flush();
                        writer = null;

                    }
                    catch
                    {
                        CloseClient(client);
                    }
                }
            }
        }
    }
}

SocketClient.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.IO;
using System.Threading;
using System.Security.Cryptography;

namespace WebSocketServer.Entities
{
    class SocketClient
    {
        public TcpClient Client;
        StreamReader reader;
        StreamWriter writer;
        Form1 parentForm;


        public SocketClient(TcpClient client, Form1 pForm)
        {
            parentForm = pForm;
            Client = client;
            Thread clientThread = new Thread(new ThreadStart(StartClient));
            clientThread.Start();
        }


        private void StartClient()
        {
            SocketServer.ClientList.Add(this);
            // create a reader for this client
            reader = new StreamReader(Client.GetStream());
            // create a writer for this client
            writer = new StreamWriter(Client.GetStream());

            var headers = new Dictionary<string, string>();

            string line = "";
            while ((line = reader.ReadLine()) != string.Empty)
            {
                if (!string.IsNullOrEmpty(line))
                {
                    var tokens = line.Split(new char[] { ':' }, 2);
                    if (!string.IsNullOrWhiteSpace(line) && tokens.Length > 1)
                    {
                        headers[tokens[0]] = tokens[1].Trim();
                    }
                }
            }


            String secWebSocketAccept = ComputeWebSocketHandshakeSecurityHash09(headers["Sec-WebSocket-Key"]);

            // send handshake to this client only
            writer.WriteLine("HTTP/1.1 101 Web Socket Protocol Handshake");
            writer.WriteLine("Upgrade: WebSocket");
            writer.WriteLine("Connection: Upgrade");
            writer.WriteLine("WebSocket-Origin: http://localhost:63422/");
            writer.WriteLine("WebSocket-Location: ws://localhost:8181/websession");
            writer.WriteLine("Sec-WebSocket-Accept: " + secWebSocketAccept);
            writer.WriteLine("");
            writer.Flush();

            SocketServer.SendBroadcast("New Client Connected");

            Thread clientRun = new Thread(new ThreadStart(RunClient));
            clientRun.Start();
        }

        public static String ComputeWebSocketHandshakeSecurityHash09(String secWebSocketKey)
         {
             const String MagicKEY = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
             String secWebSocketAccept = String.Empty;

             // 1. Combine the request Sec-WebSocket-Key with magic key.
             String ret = secWebSocketKey + MagicKEY;

             // 2. Compute the SHA1 hash
             SHA1 sha = new SHA1CryptoServiceProvider(); 
             byte[] sha1Hash = sha.ComputeHash(Encoding.UTF8.GetBytes(ret));

             // 3. Base64 encode the hash
             secWebSocketAccept = Convert.ToBase64String(sha1Hash);

             return secWebSocketAccept;
         }


        private void RunClient()
        {
            try
            {
                string line = "";
                while (true)
                {
                    line = reader.ReadLine();
                    if (!string.IsNullOrEmpty(line))
                    {
                        parentForm.ApplyText(line + "\r\n");
                        SocketServer.SendBroadcast(line);
                    }
                }
            }
            catch
            {
                parentForm.ApplyText("Client Disconnected\r\n");
                SocketServer.CloseClient(this);
            }
        }

        public void Dispose()
        {
            System.GC.SuppressFinalize(this);
        }
    }

}

我可以在Chrome中连接多个实例，我的服务器显示所有连接的客户端，并且我看到握手成功的警报。但是当我尝试从客户端发送文本（上面未显示代码，但它是一种相当简单的ws.send(text)）时，它以乱码文本形式传送到服务器。当我尝试从服务器向客户端执行writer.WriteLine("whatever")时，onmessage事件从未触发。在我最终解决了握手问题之后，我进行了大量搜索，找不到任何解决此问题的好示例。

我应该不使用StreamWriter吗？我在握手中漏掉了其他内容吗（可能是协议）？

感谢您的帮助和查看。

编辑：

下面的代码是有效的，但我不知道如何修改它以允许动态大小的文本长度。目前，我可以发送127个字符或更少的文本，但似乎无法处理超过4个字符的情况。

public static void SendBroadcast(string text)
{
    StreamWriter writer;
    // loop through the array and send text to all clients
    foreach (SocketClient client in ClientList)
    {
        if (client.Client.Connected)
        {
            try
            {
                NetworkStream l_Stream = client.Client.GetStream();  
                List<byte> lb = new List<byte>();
                lb.Add(0x81);
                lb.Add(0x04);
                lb.AddRange(Encoding.UTF8.GetBytes("test"));
                l_Stream.Write(lb.ToArray(), 0, 6);
            }
            catch
            {
                CloseClient(client);
            }
        }
    }
}

我已经尝试将lb.Add（0x04）修改为lb.Add（0x07），并发送“testing”，但没有成功。我也不明白l_Stream.Write（）参数是什么。我知道这是字节数组，偏移量和大小，但大小是什么？

- Christopher Johnson

2个回答

2

我遇到了同样的问题，我找到了解决方法：

            lb = new List<byte>();
            lb.Add(0x81);
            size = message.Length;//get the message's size
            lb.Add((byte)size); //get the size in bytes
            lb.AddRange(Encoding.UTF8.GetBytes(message));
            stream.Write(lb.ToArray(), 0, size+2); //I do size+2 because we have 2 bytes plus 0x81 and (byte)size

使用此解决方案，您可以发送更大的消息，但只能 < 127 字符。

注意：抱歉，我的英语不太好。^^

- ralph

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- simonc · Accepted Answer

最新版本的规范中，消息不以纯文本形式发送。有关详细信息，请参见数据帧部分。

这篇维基文章也非常有用。

我还写了一个C++服务器；WsProtocol80类展示了如何读取/写入数据。

编辑：在您的示例发送代码中，0x04字节指定了4字节的消息。您可以设置不同的值并以此方式发送长达125字节的消息。当您更改消息长度时，还必须更新l_Stream.Write的最后一个参数（它指定要写入的字节数）。在所有情况下将其更改为lb.Count似乎更好。

如果您仍然对位运算感到困惑，并且稍后想要发送更长的消息或从客户端读取消息，则上面链接的维基帖子中包含的伪代码应该会很有帮助。