AJAX在C#中處理WebSocket消息隊列的方法

在C#中，使用AJAX處理WebSocket消息隊列需要以下幾個步驟：

1. 首先，創建一個ASP.NET Core Web應用程序，并添加WebSocket支持。在Startup.cs文件中，配置WebSocket中間件：

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    // ...
    app.UseWebSockets();
    // ...
}

2. 創建一個WebSocket處理器類，用于處理客戶端連接和消息：

public class WebSocketHandler : IWebSocketHandler
{
    private List<WebSocket> _clients = new List<WebSocket>();

    public async Task OnConnected(WebSocket socket)
    {
        _clients.Add(socket);
        await SendMessageToAllAsync("New client connected");
    }

    public async Task OnDisconnected(WebSocket socket)
    {
        _clients.Remove(socket);
        await SendMessageToAllAsync("Client disconnected");
    }

    public async Task OnMessageReceived(WebSocket socket, string message)
    {
        await SendMessageToAllAsync($"Received message: {message}");
    }

    private async Task SendMessageToAllAsync(string message)
    {
        foreach (var client in _clients)
        {
            if (client.State == WebSocketState.Open)
            {
                await client.SendAsync(Encoding.UTF8.GetBytes(message), WebSocketMessageType.Text, true, CancellationToken.None);
            }
        }
    }
}

3. 在Startup.cs文件中，將WebSocket處理器注冊為服務：

public void ConfigureServices(IServiceCollection services)
{
    // ...
    services.AddSingleton<IWebSocketHandler, WebSocketHandler>();
    // ...
}

4. 創建一個API控制器，用于處理客戶端的WebSocket連接請求：

[Route("api/websocket")]
public class WebSocketController : ControllerBase
{
    private readonly IWebSocketHandler _webSocketHandler;

    public WebSocketController(IWebSocketHandler webSocketHandler)
    {
        _webSocketHandler = webSocketHandler;
    }

    [HttpGet]
    public async Task Get()
    {
        if (HttpContext.WebSockets.IsWebSocketRequest)
        {
            var webSocket = await HttpContext.WebSockets.AcceptWebSocketAsync();
            await _webSocketHandler.OnConnected(webSocket);

            await ReceiveLoop(webSocket);
        }
        else
        {
            HttpContext.Response.StatusCode = (int)HttpStatusCode.BadRequest;
        }
    }

    private async Task ReceiveLoop(WebSocket webSocket)
    {
        var buffer = new byte[1024 * 4];
        var result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);

        while (!result.CloseStatus.HasValue)
        {
            var message = Encoding.UTF8.GetString(buffer, 0, result.Count);
            await _webSocketHandler.OnMessageReceived(webSocket, message);

            result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
        }

        await _webSocketHandler.OnDisconnected(webSocket);
        await webSocket.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
    }
}

5. 在客戶端（例如JavaScript）中，使用AJAX發送請求到WebSocket API，并處理收到的消息：

// 創建WebSocket連接
const socket = new WebSocket('ws://localhost:5000/api/websocket');

// 連接打開時觸發
socket.onopen = (event) => {
    console.log('WebSocket connection opened:', event);
};

// 收到消息時觸發
socket.onmessage = (event) => {
    console.log('WebSocket message received:', event.data);
};

// 連接關閉時觸發
socket.onclose = (event) => {
    console.log('WebSocket connection closed:', event);
};

// 發送消息
function sendMessage(message) {
    socket.send(message);
}

現在，當客戶端通過AJAX發送消息時，服務器會將消息廣播給所有連接的客戶端。這樣，你就可以使用AJAX處理WebSocket消息隊列了。