WebSocket使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据。在WebSocket API中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输。

WebSocket与http

其实从历史上来讲，websocket是为了克服http无法双向通信而引入的，在通常的使用中，可以复用http的端口与功能，除此外，他们没有其他的联系，而是完全是独立的协议，通常情况下，http是单向的web 服务，而websocket是全双工的，服务器和客户端可以实时的传输信息，在引用时他们可以在http服务器上同时部署，特别是在NodeJs中。

WebSocket与Socket 

那么websocket和socket是什么关系呢？ 其实可以理解为websocket是在socket的基础上实现的，其基于消息帧和TCP协议，而socket更通用，在编程中，可以选在tcp，udp，也需要自己控制数据流格式，每次的数据的长度都需要自己控制与读取。

下边记录两种Unity客户端使用WebSocket的方法。

1.不使用插件的客户端

引入System.Net.WebSockets;命名空间。

在使用过程中发现这种方法打包WebGl的的时候是存在问题的。

具体使用方法如下：

WebSocket 类 (System.Net.WebSockets) | Microsoft Learn

 Unity客户端代码：

using System;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using UnityEngine;
using UnityEngine.UI;

public class test4 : MonoBehaviour
{
    private void Start()
    {
        WebSocket();
    }

    public async void WebSocket()
    {
        try
        {
            ClientWebSocket ws = new ClientWebSocket();
            CancellationToken ct = new CancellationToken();
            //添加header
            //ws.Options.SetRequestHeader("X-Token", "eyJhbGciOiJIUzI1N");
            Uri url = new Uri("ws://xxx.xxx.xxx.xx:18x/xxx/xxx");
            await ws.ConnectAsync(url, ct);
            await ws.SendAsync(new ArraySegment<byte>(Encoding.UTF8.GetBytes("hello")), WebSocketMessageType.Binary, true, ct); //发送数据

            while (true)
            {
                var result = new byte[1024];
                await ws.ReceiveAsync(new ArraySegment<byte>(result), new CancellationToken());//接受数据
                var str = Encoding.UTF8.GetString(result, 0, result.Length);
                Debug.Log(str);
            }
          
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }

}

2.使用Best HTTP插件

这款插件不但支持WebSockets，还支持HTTP，Sockets等通信方式是一款不错的插件。也支持打包Webgl

插件地址：

https://download.csdn.net/download/f402455894/87597949?spm=1001.2014.3001.5501

客户端代码：

using UnityEngine;
using System;
using BestHTTP.WebSocket;
using Newtonsoft.Json;

public class GaoYaGuHuaLu : MonoBehaviour
{

     string address = "ws://10.xxx.xx.193:1880/xxx";

    WebSocket webSocket;

    public GaoYaGuHuaLuEntity gaoYaGuHuaLu = new GaoYaGuHuaLuEntity();

    private void Awake()
    {
       
    }
    private void Start()
    {
        Init();
    }
    public void Init()
    {
        if (webSocket == null)
        {
            webSocket = new WebSocket(new Uri(address));

#if !UNITY_WEBGL
            webSocket.StartPingThread = true;
#endif

            // Subscribe to the WS events
            webSocket.OnOpen += OnOpen;
            webSocket.OnMessage += OnMessageRecv;
            webSocket.OnBinary += OnBinaryRecv;
            webSocket.OnClosed += OnClosed;
            webSocket.OnError += OnError;

            // Start connecting to the server
            webSocket.Open();
        }
    }


    public void Destroy()
    {
        if (webSocket != null)
        {
            webSocket.Close();
            webSocket = null;
        }
    }

    void OnOpen(WebSocket ws)
    {
        Debug.Log("OnOpen: ");
      //  webSocket.Send("我来啦");
    }


    void OnMessageRecv(WebSocket ws, string message)
    {
        Debug.LogFormat("OnMessageRecv: msg={0}", message);

    }

    void OnBinaryRecv(WebSocket ws, byte[] data)
    {
        Debug.LogFormat("OnBinaryRecv: len={0}", data.Length);
    }

    void OnClosed(WebSocket ws, UInt16 code, string message)
    {
        Debug.LogFormat("OnClosed: code={0}, msg={1}", code, message);
        webSocket = null;
    }

    void OnError(WebSocket ws, string ex)
    {
        string errorMsg = string.Empty;
#if !UNITY_WEBGL || UNITY_EDITOR
        if (ws.InternalRequest.Response != null)
        {
            errorMsg = string.Format("Status Code from Server: {0} and Message: {1}", ws.InternalRequest.Response.StatusCode, ws.InternalRequest.Response.Message);
        }
#endif
        Debug.LogFormat("OnError: error occured: {0}\n", (ex != null ? ex : "Unknown Error " + errorMsg));
        webSocket = null;
    }

    public void OnClose()
    {
        // 关闭连接
        webSocket.Close(1000, "Bye!");
    }
}

加上心跳检测和断线重连

using UnityEngine;
using System;
using System.Collections;
using System.Collections.Generic;
using BestHTTP;
using BestHTTP.WebSocket;
using BestHTTP.Examples;


public class ZGAndroidcCient : MonoBehaviour
{
    // w ws://XXXX:7799
    public string address = "ws://XXXX:7799";


    WebSocket webSocket;
    private bool lockReconnect = false;
    private Coroutine _pingCor, _clientPing, _serverPing;

    private void Start()
    {
        CreateWebSocket();
    }

    void CreateWebSocket()
    {
        try
        {
            webSocket = new WebSocket(new Uri(address));
#if !UNITY_WEBGL
            webSocket.StartPingThread = true;
#endif
            InitHandle();
            webSocket.Open();
        }
        catch (Exception e)
        {
            Debug.Log("websocket连接异常:" + e.Message);
            ReConnect();
        }

    }

    private void Update()
    {
        Debug.Log(lockReconnect);
    }

    void InitHandle()
    {
        RemoveHandle();
        webSocket.OnOpen += OnOpen;
        webSocket.OnMessage += OnMessageReceived;
        webSocket.OnClosed += OnClosed;
        webSocket.OnError += OnError;
    }

    void RemoveHandle()
    {
        webSocket.OnOpen -= OnOpen;
        webSocket.OnMessage -= OnMessageReceived;
        webSocket.OnClosed -= OnClosed;
        webSocket.OnError -= OnError;
    }

    void OnOpen(WebSocket ws)
    {
        Debug.Log("websocket连接成功");
        webSocket.Send("一个客户端连过来了");
        if (_pingCor != null)
        {
            StopCoroutine(_pingCor);
            _pingCor = null;
        }
        _pingCor = StartCoroutine(HeartPing());
        // 心跳检测重置
        HeartCheck();
    }

    void OnMessageReceived(WebSocket ws, string message)
    {
        // 如果获取到消息，心跳检测重置
        // 拿到任何消息都说明当前连接是正常的
        HeartCheck();
        Debug.Log(message);
    }

    void OnClosed(WebSocket ws, UInt16 code, string message)
    {
        Debug.LogFormat("OnClosed: code={0}, msg={1}", code, message);
        webSocket = null;
        ReConnect();
    }

    void OnError(WebSocket ws, string ex)
    {
        string errorMsg = string.Empty;
#if !UNITY_WEBGL || UNITY_EDITOR
        if (ws.InternalRequest.Response != null)
        {
            errorMsg = string.Format("Status Code from Server: {0} and Message: {1}", ws.InternalRequest.Response.StatusCode, ws.InternalRequest.Response.Message);
        }
#endif
        Debug.LogFormat("OnError: error occured: {0}\n", (ex != null ? ex : "Unknown Error " + errorMsg));
        webSocket = null;
        ReConnect();

    }

    void ReConnect()
    {
        if (this.lockReconnect)
            return;
        this.lockReconnect = true;
        StartCoroutine(SetReConnect());
    }

    private IEnumerator SetReConnect()
    {
        Debug.Log("正在重连websocket");
        yield return new WaitForSeconds(5);
        CreateWebSocket();
        lockReconnect = false;
    }

    //心跳检测
    private void HeartCheck()
    {
        if (_clientPing != null)
        {
            StopCoroutine(_clientPing);
            _clientPing = null;
        }
        if (_serverPing != null)
        {
            StopCoroutine(_serverPing);
            _serverPing = null;
        }
        _clientPing = StartCoroutine(ClientPing());
    }

    // 这里发送一个心跳，后端收到后，返回一个心跳消息
    // onmessage拿到返回的心跳就说明连接正常
    private IEnumerator ClientPing()
    {
        yield return new WaitForSeconds(5);
        WebSend("heartbeat");
        _serverPing = StartCoroutine(ServerPing());
    }
    // 如果超过一定时间还没重置，说明后端主动断开了
    // 如果onclose会执行reconnect，我们执行ws.close()就行了.如果直接执行reconnect 会触发onclose导致重连两次
    private IEnumerator ServerPing()
    {
        yield return new WaitForSeconds(5);
        if (webSocket != null)
        {
            webSocket.Close();
        }
      
    }

    //发送心跳
    private IEnumerator HeartPing()
    {
        while (true)
        {
            yield return new WaitForSeconds(5);
            this.WebSend("Heartbeat");
        }
    }
    //向服务端发送信息
    public void WebSend(string msg)
    {
        if (webSocket == null || string.IsNullOrEmpty(msg)) return;
        if (webSocket.IsOpen)
        {
            webSocket.Send(msg);
        }
    }

    public void OnClose()
    {
        // 关闭连接
        webSocket.Close(1000, "Bye!");
    }


}