WebSocket ， C#实现服务端

最近测试了一下WebSocket ， 服务端WebSocket使用C#的原生ssocket实现。前端使用js的WebSocket
值得提醒的是本次测试的重点：
①：前端和后端额外的握手
②：后端取得前端数据后如何解析
③：后端往前端发数据的打包流程

后端Socket核心

using System;
using System.ComponentModel;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Linq;
using SWebSocketLib.com;
namespace SWebSocketLib
{
/// <summary>
/// WebSocket
/// </summary>
public sealed class WebSocket_Service
{

byte[] buffer = new byte[1024];
private Socket _listener = null;//服务端Socket
private readonly IPEndPoint _ip_port = null;
private readonly int _listen_count = 0;
private Action<Socket_CallBack_Type, Object, Socket> _callback = null;
public WebSocket_Service( IPEndPoint ip_port , Action<Socket_CallBack_Type , Object , Socket> callback ,int listen_count = 100 )
{
this._ip_port = ip_port;
this._callback = callback;
this._listen_count = listen_count;
}
/// <summary>
/// 启动监听
/// </summary>
public void Start()
{
if (this._listener == null)
this._listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
this._listener.Bind(this._ip_port);
this._listener.Listen(this._listen_count);
this.accept();
}
/// <summary>
/// 等待连接
/// </summary>
private void accept()
{
Console.WriteLine("等待客户端连接....");
Socket sc = _listener.Accept();//接受一个连接
Console.WriteLine("接受到了客户端：" + sc.RemoteEndPoint.ToString() + "连接....");
this.Receive2HandShake(sc);
}
#region 正式接收客户端信息
private void Receive2Msg(Socket client)
{
Console.WriteLine("等待客户端数据....");
int length = client.Receive(buffer);//接受客户端信息
if (length > 0)
{
string clientMsg = AnalyticData(buffer, length);
Console.WriteLine("接受到客户端数据：" + clientMsg);
if (clientMsg == @"Hello , I am Egret Test By Aonaufly")
{
this._callback(Socket_CallBack_Type.connect_succ, null, client);//发送连接成功信息
}
//this.Receive2Msg(client);
}
else
{
client.Disconnect(true);
}
}
#endregion
#region 向服务端发送信息
public void Send2Msg(Socket client, string clientMsg)
{
Console.WriteLine("==发送数据：" + clientMsg + " 至客户端....");
byte[] body = Encoding.UTF8.GetBytes(clientMsg);
byte[] c = this.PackData(body);
Console.WriteLine("数据的大小 ： {0} / 包的大小 ： {1}", body.Length , c.Length);
client.Send(c);
}
#endregion
#region 接收客户端发来的握手信息并返回握手信息
/// <summary>
/// 第四次握手信息处理
/// </summary>
/// <param name="client"></param>
private void Receive2HandShake(Socket client)
{
int length = client.Receive(buffer);
if (length > 0)
{
client.Send(PackHandShakeData(GetSecKeyAccetp(buffer, length)));
Console.WriteLine("已经发送握手协议了....");
this.Receive2Msg(client);
}
else
{
client.Disconnect(true);
}
}
#endregion
#region WebSocket的的四次额外握手信息
/// <summary>
/// 打包握手信息
/// </summary>
/// <param name="secKeyAccept"></param>
/// <returns></returns>
private static byte[] PackHandShakeData(string secKeyAccept)
{
var responseBuilder = new StringBuilder();
responseBuilder.Append("HTTP/1.1 101 Switching Protocols" + Environment.NewLine);
responseBuilder.Append("Upgrade: websocket" + Environment.NewLine);
responseBuilder.Append("Connection: Upgrade" + Environment.NewLine);
responseBuilder.Append("Sec-WebSocket-Accept: " + secKeyAccept + Environment.NewLine + Environment.NewLine);
return Encoding.UTF8.GetBytes(responseBuilder.ToString());
}
/// <summary>
/// 生成Sec-WebSocket-Accept
/// </summary>
/// <param name="handShakeText">客户端握手信息</param>
/// <returns>Sec-WebSocket-Accept</returns>
private static string GetSecKeyAccetp(byte[] handShakeBytes, int bytesLength)
{
string handShakeText = Encoding.UTF8.GetString(handShakeBytes, 0, bytesLength);
string key = string.Empty;
Regex r = new Regex(@"Sec\-WebSocket\-Key:(.*?)\r\n");
Match m = r.Match(handShakeText);
if (m.Groups.Count != 0)
{
key = Regex.Replace(m.Value, @"Sec\-WebSocket\-Key:(.*?)\r\n", "$1").Trim();
}
byte[] encryptionString = SHA1.Create().ComputeHash(Encoding.ASCII.GetBytes(key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));
return Convert.ToBase64String(encryptionString);
}
#endregion
#region 解析客户端数据
/// <summary>
/// 解析客户端数据包
/// </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 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);
}
#endregion
#region 打包要发送的数据
/// <summary>
/// 打包服务器数据
/// </summary>
/// <param name="message">需要打包的数据（通讯用）</param>
/// <returns>数据包</returns>
private byte[] PackData(byte[] message)
{
byte[] contentBytes = null;
if (message.Length < 126)
{
contentBytes = new byte[message.Length + 2];
contentBytes[0] = 0x81;
contentBytes[1] = (byte)message.Length;
Array.Copy(message, 0, contentBytes, 2, message.Length);
}
else if (message.Length < 0xFFFF)
{
contentBytes = new byte[message.Length + 4];
contentBytes[0] = 0x81;
contentBytes[1] = 126;

contentBytes[2] = (byte)(message.Length & 0xFF);
contentBytes[3] = (byte)(message.Length >> 8 & 0xFF);
Array.Copy(message, 0, contentBytes, 4, message.Length);
}
else
{
contentBytes = new byte[message.Length + 10];
contentBytes[0] = 0x81;
contentBytes[1] = 127;
byte[] ulonglen = BitConverter.GetBytes((long)message.Length);
contentBytes[2] = ulonglen[7];
contentBytes[3] = ulonglen[6];
contentBytes[4] = ulonglen[5];
contentBytes[5] = ulonglen[4];
contentBytes[6] = ulonglen[3];
contentBytes[7] = ulonglen[2];
contentBytes[8] = ulonglen[1];
contentBytes[9] = ulonglen[0];
Array.Copy(message, 0, contentBytes, 10, message.Length);
}
return contentBytes;
}
#endregion

}
/// <summary>
/// Socket回调类型
/// </summary>
public enum Socket_CallBack_Type : uint
{
[Description("连接成功")]
connect_succ = 0,
[Description("连接失败")]
connect_fail = 1,
[Description("接收返回")]
receive = 2,
[Description("发送返回")]
send = 3,
[Description("客户端被迫断开")]
client_passive_off = 4,
[Description("客户端主动断开")]
client_active_off = 5
}
}

讲解 ：
①：关于握手（websocket存在第四次额外的握手），客户端请求连接服务器后，服务器会根据客户端发来的信息，生成一个握手信息发给客户端完成最后一次额外的握手。
以下是服务端生成握手信息的核心代码 ：

/// <summary>
/// 打包握手信息
/// </summary>
/// <param name="secKeyAccept"></param>
/// <returns></returns>
private static byte[] PackHandShakeData(string secKeyAccept)
{
var responseBuilder = new StringBuilder();
responseBuilder.Append("HTTP/1.1 101 Switching Protocols" + Environment.NewLine);
responseBuilder.Append("Upgrade: websocket" + Environment.NewLine);
responseBuilder.Append("Connection: Upgrade" + Environment.NewLine);
responseBuilder.Append("Sec-WebSocket-Accept: " + secKeyAccept + Environment.NewLine + Environment.NewLine);
return Encoding.UTF8.GetBytes(responseBuilder.ToString());
}
/// <summary>
/// 生成Sec-WebSocket-Accept
/// </summary>
/// <param name="handShakeText">客户端握手信息</param>
/// <returns>Sec-WebSocket-Accept</returns>
private static string GetSecKeyAccetp(byte[] handShakeBytes, int bytesLength)
{
string handShakeText = Encoding.UTF8.GetString(handShakeBytes, 0, bytesLength);
string key = string.Empty;
Regex r = new Regex(@"Sec\-WebSocket\-Key:(.*?)\r\n");
Match m = r.Match(handShakeText);
if (m.Groups.Count != 0)
{
key = Regex.Replace(m.Value, @"Sec\-WebSocket\-Key:(.*?)\r\n", "$1").Trim();
}
byte[] encryptionString = SHA1.Create().ComputeHash(Encoding.ASCII.GetBytes(key + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"));
return Convert.ToBase64String(encryptionString);
}

②：关于解析客户端发来的信息（目前只解析成String ， 可以在此方法上扩展的）

/// <summary>
/// 解析客户端数据包
/// </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 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);
}

③：发送到客户端的信息也是需要打包的

/// <summary>
/// 打包服务器数据
/// </summary>
/// <param name="message">需要打包的数据（通讯用）</param>
/// <returns>数据包</returns>
private byte[] PackData(byte[] message)
{
byte[] contentBytes = null;
if (message.Length < 126)
{
contentBytes = new byte[message.Length + 2];
contentBytes[0] = 0x81;
contentBytes[1] = (byte)message.Length;
Array.Copy(message, 0, contentBytes, 2, message.Length);
}
else if (message.Length < 0xFFFF)
{
contentBytes = new byte[message.Length + 4];
contentBytes[0] = 0x81;
contentBytes[1] = 126;

contentBytes[2] = (byte)(message.Length & 0xFF);
contentBytes[3] = (byte)(message.Length >> 8 & 0xFF);
Array.Copy(message, 0, contentBytes, 4, message.Length);
}
else
{
contentBytes = new byte[message.Length + 10];
contentBytes[0] = 0x81;
contentBytes[1] = 127;
byte[] ulonglen = BitConverter.GetBytes((long)message.Length);
contentBytes[2] = ulonglen[7];
contentBytes[3] = ulonglen[6];
contentBytes[4] = ulonglen[5];
contentBytes[5] = ulonglen[4];
contentBytes[6] = ulonglen[3];
contentBytes[7] = ulonglen[2];
contentBytes[8] = ulonglen[1];
contentBytes[9] = ulonglen[0];
Array.Copy(message, 0, contentBytes, 10, message.Length);
}
return contentBytes;
}

客户端 （index.html）

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
<title>Testing websockets</title>
</head>
<body>
<button id="start">click to start</button>
<div id="messages"></div>

<script type="text/javascript">
var button = document.getElementById("start");
button.onclick = function () {
var websocketAddr = "ws://192.168.1.104:6065/";
var webSocket = new WebSocket(websocketAddr);
webSocket.onopen = function (event) {
document.getElementById('messages').innerHTML
= '消息通道开启，可以发送消息了';
webSocket.send('Hello , I am Egret Test By Aonaufly');
};
webSocket.onmessage = function (event) {
document.getElementById('messages').innerHTML
+= '<br />来自服务器的消息' + event.data;
};
webSocket.onerror = function (event) {
alert(event.data);
};
}
</script>
</body>
</html>

测试结果:

服务端




客户端



实现了一次完美的通讯。