websocket与C# socket相互通信

松風水月 · 发表于 2023-4-23 13:54:04

web端代码就是js代码，C#有两种方式：使用第三方库，如Fleck，使用C#原生socket编程实现 web端：

<!doctype html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<title>下发网站上文件到学生机</title>
</head>
<body>
<table border="1" cellspacing="0">
<tr>
<th>试卷号</th>
<th>试卷名称</th>
<th>描述</th>
<th>操作</th>
</tr>
<tr>
<td>JCLX01</td>
<td>基础练习一</td>
<td>建账、会计期间设置、部门职员设置、银行账户设置、科目设置等</td>
<td><button id="btnDownload" onclick="callDesktopReceiveFile(this)">下发</button></td>
</tr>
<tr>
<td>JCLX02</td>
<td>基础练习二</td>
<td>建账、会计期间设置、部门职员设置、银行账户设置、科目设置等</td>
<td><button id="btnDownload" onclick="callDesktopReceiveFile(this)">下发</button></td>
</tr>
</table>
</body>
</html>

复制代码

C#端方式一：使用第三方库Fleck参考：http://chanpinxue.cn/archives/979.html 方式二：使用C#原生socket编程自行实现

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using U8FileTransfer.TcpHelper;
using System.Net.Sockets;
using System.Net;
using System.Security.Cryptography;
namespace CodeExperiment
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
Thread thread = new Thread(websocketListen);
thread.IsBackground = true;
thread.Start();
}
/// <summary>
/// 解析客户端数据包，防止乱码
/// </summary>
/// <param name="recBytes">服务器接收的数据包</param>
/// <param name="recByteLength">有效数据长度</param>
/// <returns></returns>
private static string AnalyticData(byte[] recBytes, int recByteLength)
{
if (recByteLength < 2) { return string.Empty; }
bool fin = (recBytes[0] & 0x80) == 0x80; // 1bit，1表示最后一帧
if (!fin)
{
return string.Empty;// 超过一帧暂不处理
}
bool mask_flag = (recBytes[1] & 0x80) == 0x80; // 是否包含掩码
if (!mask_flag)
{
return string.Empty;// 不包含掩码的暂不处理
}
int payload_len = recBytes[1] & 0x7F; // 数据长度
byte[] masks = new byte[4];
byte[] payload_data;
if (payload_len == 126)
{
Array.Copy(recBytes, 4, masks, 0, 4);
payload_len = (UInt16)(recBytes[2] << 8 | recBytes[3]);
payload_data = new byte[payload_len];
Array.Copy(recBytes, 8, payload_data, 0, payload_len);
}
else if (payload_len == 127)
{
Array.Copy(recBytes, 10, masks, 0, 4);
byte[] uInt64Bytes = new byte[8];
for (int i = 0; i < 8; i++)
{
uInt64Bytes[i] = recBytes[9 - i];
}
UInt64 len = BitConverter.ToUInt64(uInt64Bytes, 0);
payload_data = new byte[len];
for (UInt64 i = 0; i < len; i++)
{
payload_data[i] = recBytes[i + 14];
}
}
else
{
Array.Copy(recBytes, 2, masks, 0, 4);
payload_data = new byte[payload_len];
Array.Copy(recBytes, 6, payload_data, 0, payload_len);
}
for (var i = 0; i < payload_len; i++)
{
payload_data[i] = (byte)(payload_data[i] ^ masks[i % 4]);
}
return Encoding.UTF8.GetString(payload_data);
}
/// <summary>
/// 打包服务器数据，防止乱码
/// </summary>
/// <param name="message">数据</param>
/// <returns>数据包</returns>
private static byte[] PackData(string message)
{
byte[] contentBytes = null;
byte[] temp = Encoding.UTF8.GetBytes(message);
if (temp.Length < 126)
{
contentBytes = new byte[temp.Length + 2];
contentBytes[0] = 0x81;
contentBytes[1] = (byte)temp.Length;
Array.Copy(temp, 0, contentBytes, 2, temp.Length);
}
else if (temp.Length < 0xFFFF)
{
contentBytes = new byte[temp.Length + 4];
contentBytes[0] = 0x81;
contentBytes[1] = 126;
contentBytes[2] = (byte)(temp.Length & 0xFF);
contentBytes[3] = (byte)(temp.Length >> 8 & 0xFF);
Array.Copy(temp, 0, contentBytes, 4, temp.Length);
}
else
{
// 暂不处理超长内容
}
return contentBytes;
}
/// <summary>
/// 客户端消息结构化
/// message参数格式为多个key:value键值对通过分号拼接组成，示例：
/// content:download_and_send;file-url:https://www.a.com/a.zip;
///
/// </summary>
/// <param name="message"></param>
/// <returns></returns>
private Dictionary<string, string> ProcessRemoteMessage(string message)
{
Dictionary<string, string> dic = new Dictionary<string, string>();
if (message.Substring(message.Length - 1, 1) == ";")
{
message = message.Substring(0, message.Length - 1);
}
string[] strs = message.Split(';');
if (strs.Length > 0)
{
Console.WriteLine("- - - - - - - - - - - - - - - - - - -");
foreach (string s in strs)
{
Console.WriteLine(s);
string[] split = s.Split(new char[] { ':' }, 2);
Console.WriteLine("[" + split[0] + "][" + split[1] + "]");
dic.Add(split[0], split[1]);
}
Console.WriteLine("- - - - - - - - - - - - - - - - - - -");
}
return dic;
}
private void websocketListen()
{
Socket server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
EndPoint endPoint = new IPEndPoint(IPAddress.Any, 14567);//监听端口
server.Bind(endPoint);
server.Listen(10); // 排队等待连接最大数量10
// 监听多个客户端连接
while (true)
{
Socket client = server.Accept();
Console.WriteLine("有客户端连上来了");
//接收客户端发来的HTTP-Header消息
byte[] bytes = new byte[1024];
int len = client.Receive(bytes);
string strMessage = Encoding.UTF8.GetString(bytes, 0, len);
Console.WriteLine(strMessage);
//获取Sec-WebSocket-Key，为握手做准备
string[] strings = strMessage.Split('\n');
string strSecWebSocketKey = "";
foreach (var item in strings)
{
string[] strings1 = item.Split(':');
if (strings1[0] == "Sec-WebSocket-Key")
{
strSecWebSocketKey = strings1[1].Trim();
}
}
//生成服务端Sec-WebSocket-Accept，迎合客户端的握手请求
byte[] secKeyBytes = SHA1.Create().ComputeHash(Encoding.ASCII.GetBytes(strSecWebSocketKey + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));
string secKey = Convert.ToBase64String(secKeyBytes);
// 发送给客户端完成握手(会触发Websocket的open()回调函数)，针对websocket必须使用以下header
string strHeader = "";
strHeader += "HTTP/1.1 101 Switching Protocols" + Environment.NewLine;
strHeader += "Upgrade: websocket" + Environment.NewLine;
strHeader += "Connection: Upgrade" + Environment.NewLine;
strHeader += "Sec-WebSocket-Accept: " + secKey + Environment.NewLine + Environment.NewLine;
client.Send(Encoding.UTF8.GetBytes(strHeader));
string remoteFileUrl = null;
bool clientClose = false;
// 循环接收websocket发来的消息实现双方交流
while (!clientClose)
{
//接收客户端发来的消息
byte[] bytes2 = new byte[1024];
int len2 = client.Receive(bytes2);
string strMessage2 = AnalyticData(bytes2, len2);
if (strMessage2.Length > 0)
{
Console.WriteLine("客户端发来消息：{0}", strMessage2);
Dictionary<string, string> messageDic = ProcessRemoteMessage(strMessage2);
string content = null;
messageDic.TryGetValue("content", out content);
Console.WriteLine("message content：" + content);
if (content == "receiveFile")
{
messageDic.TryGetValue("url", out remoteFileUrl);
client.Send(PackData("roger"));
Console.WriteLine("remoteFileUrl: " + remoteFileUrl);
Console.WriteLine("to do invoke download.");
// 关闭连接
client.Shutdown(SocketShutdown.Both);
client.Close();
clientClose = true;
}
}
else
{
Console.WriteLine("客户端关闭了连接");
client.Shutdown(SocketShutdown.Both);
client.Close();
}
}
}
}
}
}

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websocket关闭机制通信双方都可以主动关闭连接，不管谁关闭连接，对方都能收到消息。client端关闭连接，server端能收到内容长度为0的消息。server端关闭连接，client端会触发onclose事件。
来源:https://www.cnblogs.com/jsper/archive/2023/04/23/17346323.html
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