576 lines
19 KiB
C#
576 lines
19 KiB
C#
using System.Net;
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using System.Text;
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using SixLabors.ImageSharp;
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using SixLabors.ImageSharp.Formats.Jpeg;
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using SixLabors.ImageSharp.PixelFormats;
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namespace server.Services;
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/// <summary>
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/// HTTP 视频流服务，用于从 FPGA 获取图像数据并推送到前端网页
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/// 简化版本实现，先建立基础框架
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/// </summary>
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public class HttpVideoStreamService : BackgroundService
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{
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private static readonly NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();
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private HttpListener? _httpListener;
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private readonly int _serverPort = 8080;
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private readonly int _frameRate = 30; // 30 FPS
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private readonly int _frameWidth = 640;
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private readonly int _frameHeight = 480;
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// 模拟 FPGA 图像数据
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private int _frameCounter = 0;
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private readonly List<HttpListenerResponse> _activeClients = new List<HttpListenerResponse>();
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private readonly object _clientsLock = new object();
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/// <summary>
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/// 获取当前连接的客户端数量
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/// </summary>
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public int ConnectedClientsCount
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{
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get
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{
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lock (_clientsLock)
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{
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return _activeClients.Count;
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}
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}
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}
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/// <summary>
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/// 获取服务端口
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/// </summary>
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public int ServerPort => _serverPort;
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/// <summary>
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/// 获取帧宽度
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/// </summary>
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public int FrameWidth => _frameWidth;
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/// <summary>
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/// 获取帧高度
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/// </summary>
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public int FrameHeight => _frameHeight;
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/// <summary>
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/// 获取帧率
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/// </summary>
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public int FrameRate => _frameRate;
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/// <summary>
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/// 初始化 HttpVideoStreamService
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/// </summary>
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public HttpVideoStreamService()
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{
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}
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/// <summary>
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/// 执行 HTTP 视频流服务
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/// </summary>
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/// <param name="stoppingToken">取消令牌</param>
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/// <returns>任务</returns>
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protected override async Task ExecuteAsync(CancellationToken stoppingToken)
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{
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try
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{
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logger.Info("启动 HTTP 视频流服务，端口: {Port}", _serverPort);
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// 创建 HTTP 监听器
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_httpListener = new HttpListener();
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_httpListener.Prefixes.Add($"http://localhost:{_serverPort}/");
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_httpListener.Start();
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logger.Info("HTTP 视频流服务已启动，监听端口: {Port}", _serverPort);
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// 开始接受客户端连接
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_ = Task.Run(() => AcceptClientsAsync(stoppingToken), stoppingToken);
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// 开始生成视频帧
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await GenerateVideoFrames(stoppingToken);
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}
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catch (HttpListenerException ex)
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{
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logger.Error(ex, "HTTP 视频流服务启动失败，请确保您有管理员权限或使用netsh配置URL前缀权限");
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}
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catch (Exception ex)
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{
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logger.Error(ex, "HTTP 视频流服务启动失败");
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}
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}
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private async Task AcceptClientsAsync(CancellationToken cancellationToken)
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{
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while (!cancellationToken.IsCancellationRequested && _httpListener != null && _httpListener.IsListening)
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{
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try
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{
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// 等待客户端连接
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var context = await _httpListener.GetContextAsync();
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var request = context.Request;
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var response = context.Response;
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logger.Info("新HTTP客户端连接: {RemoteEndPoint}", request.RemoteEndPoint);
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// 处理不同的请求路径
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var requestPath = request.Url?.AbsolutePath ?? "/";
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if (requestPath == "/video-stream")
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{
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// MJPEG 流请求
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_ = Task.Run(() => HandleMjpegStreamAsync(response, cancellationToken), cancellationToken);
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}
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else if (requestPath == "/snapshot")
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{
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// 单帧图像请求
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await HandleSnapshotRequestAsync(response, cancellationToken);
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}
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else if (requestPath == "/video-feed.html")
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{
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// HTML页面请求
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await SendVideoHtmlPageAsync(response);
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}
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else
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{
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// 默认返回简单的HTML页面，提供链接到视频页面
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await SendIndexHtmlPageAsync(response);
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}
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}
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catch (HttpListenerException)
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{
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// HTTP监听器可能已停止
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break;
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}
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catch (ObjectDisposedException)
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{
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// 对象可能已被释放
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break;
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}
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catch (Exception ex)
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{
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logger.Error(ex, "接受HTTP客户端连接时发生错误");
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}
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}
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}
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private async Task HandleMjpegStreamAsync(HttpListenerResponse response, CancellationToken cancellationToken)
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{
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try
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{
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// 设置MJPEG流的响应头
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response.ContentType = "multipart/x-mixed-replace; boundary=--boundary";
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response.Headers.Add("Cache-Control", "no-cache, no-store, must-revalidate");
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response.Headers.Add("Pragma", "no-cache");
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response.Headers.Add("Expires", "0");
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// 跟踪活跃的客户端
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lock (_clientsLock)
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{
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_activeClients.Add(response);
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}
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logger.Debug("已启动MJPEG流，客户端: {RemoteEndPoint}", response.OutputStream?.GetHashCode() ?? 0);
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// 保持连接直到取消或出错
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try
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{
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while (!cancellationToken.IsCancellationRequested)
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{
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await Task.Delay(100, cancellationToken); // 简单的保活循环
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}
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}
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catch (TaskCanceledException)
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{
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// 预期的取消
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}
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logger.Debug("MJPEG流已结束，客户端: {ClientId}", response.OutputStream?.GetHashCode() ?? 0);
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}
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catch (Exception ex)
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{
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logger.Error(ex, "处理MJPEG流时出错");
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}
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finally
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{
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lock (_clientsLock)
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{
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_activeClients.Remove(response);
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}
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try
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{
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response.Close();
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}
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catch
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{
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// 忽略关闭时的错误
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}
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}
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}
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private async Task HandleSnapshotRequestAsync(HttpListenerResponse response, CancellationToken cancellationToken)
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{
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try
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{
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// 获取当前帧
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var imageData = await GetFPGAImageData();
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var jpegData = ConvertToJpeg(imageData);
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// 设置响应头
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response.ContentType = "image/jpeg";
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response.ContentLength64 = jpegData.Length;
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response.Headers.Add("Cache-Control", "no-cache, no-store, must-revalidate");
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// 发送JPEG数据
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await response.OutputStream.WriteAsync(jpegData, 0, jpegData.Length, cancellationToken);
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await response.OutputStream.FlushAsync(cancellationToken);
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logger.Debug("已发送快照图像，大小：{Size} 字节", jpegData.Length);
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}
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catch (Exception ex)
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{
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logger.Error(ex, "处理快照请求时出错");
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}
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finally
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{
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response.Close();
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}
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}
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private async Task SendVideoHtmlPageAsync(HttpListenerResponse response)
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{
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string html = $@"
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<!DOCTYPE html>
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<html>
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<head>
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<title>FPGA 视频流</title>
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<meta charset=""utf-8"">
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<style>
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body {{ font-family: Arial, sans-serif; text-align: center; margin: 20px; }}
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h1 {{ color: #333; }}
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.video-container {{ margin: 20px auto; max-width: 800px; }}
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.controls {{ margin: 10px 0; }}
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img {{ max-width: 100%; border: 1px solid #ddd; }}
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button {{ padding: 8px 16px; margin: 0 5px; cursor: pointer; }}
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</style>
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</head>
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<body>
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<h1>FPGA 实时视频流</h1>
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<div class=""video-container"">
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<img id=""videoStream"" src=""/video-stream"" alt=""FPGA视频流"" />
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</div>
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<div class=""controls"">
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<button onclick=""document.getElementById('videoStream').src='/snapshot?t=' + new Date().getTime()"">刷新快照</button>
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<button onclick=""document.getElementById('videoStream').src='/video-stream'"">开始流媒体</button>
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<span id=""status"">状态: 连接中...</span>
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</div>
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<script>
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document.getElementById('videoStream').onload = function() {{
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document.getElementById('status').textContent = '状态: 已连接';
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}};
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document.getElementById('videoStream').onerror = function() {{
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document.getElementById('status').textContent = '状态: 连接错误';
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}};
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</script>
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</body>
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</html>
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";
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response.ContentType = "text/html";
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response.ContentEncoding = Encoding.UTF8;
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byte[] buffer = Encoding.UTF8.GetBytes(html);
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response.ContentLength64 = buffer.Length;
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await response.OutputStream.WriteAsync(buffer, 0, buffer.Length);
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response.Close();
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}
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private async Task SendIndexHtmlPageAsync(HttpListenerResponse response)
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{
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string html = $@"
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<!DOCTYPE html>
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<html>
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<head>
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<title>FPGA WebLab 视频服务</title>
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<meta charset=""utf-8"">
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<style>
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body {{ font-family: Arial, sans-serif; text-align: center; margin: 20px; }}
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h1 {{ color: #333; }}
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.links {{ margin: 20px; }}
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a {{ padding: 10px 15px; background-color: #4CAF50; color: white; text-decoration: none; border-radius: 4px; margin: 5px; display: inline-block; }}
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a:hover {{ background-color: #45a049; }}
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</style>
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</head>
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<body>
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<h1>FPGA WebLab 视频服务</h1>
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<div class=""links"">
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<a href=""/video-feed.html"">观看实时视频</a>
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<a href=""/snapshot"" target=""_blank"">获取当前快照</a>
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</div>
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<p>HTTP流媒体服务端口: {_serverPort}</p>
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</body>
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</html>
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";
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response.ContentType = "text/html";
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response.ContentEncoding = Encoding.UTF8;
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byte[] buffer = Encoding.UTF8.GetBytes(html);
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response.ContentLength64 = buffer.Length;
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await response.OutputStream.WriteAsync(buffer, 0, buffer.Length);
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response.Close();
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}
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private async Task GenerateVideoFrames(CancellationToken cancellationToken)
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{
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var frameInterval = TimeSpan.FromMilliseconds(1000.0 / _frameRate);
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while (!cancellationToken.IsCancellationRequested)
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{
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try
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{
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// 从 FPGA 获取图像数据（模拟）
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var imageData = await GetFPGAImageData();
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// 将图像数据转换为 JPEG
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var jpegData = ConvertToJpeg(imageData);
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// 向所有连接的客户端发送帧
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await BroadcastFrameAsync(jpegData, cancellationToken);
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_frameCounter++;
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// 等待下一帧
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await Task.Delay(frameInterval, cancellationToken);
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}
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catch (OperationCanceledException)
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{
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break;
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}
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catch (Exception ex)
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{
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logger.Error(ex, "生成视频帧时发生错误");
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await Task.Delay(1000, cancellationToken); // 错误恢复延迟
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}
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}
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}
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/// <summary>
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/// 模拟从 FPGA 获取图像数据的函数
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/// 实际实现时，这里应该通过 UDP 连接读取 FPGA 特定地址范围的数据
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/// </summary>
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private async Task<byte[]> GetFPGAImageData()
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{
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// 模拟异步 FPGA 数据读取
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await Task.Delay(1);
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// 简化的模拟图像数据生成
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var random = new Random(_frameCounter);
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var imageData = new byte[_frameWidth * _frameHeight * 3]; // RGB24 格式
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// 生成简单的彩色噪声图案
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for (int i = 0; i < imageData.Length; i += 3)
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{
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// 基于帧计数器和位置生成颜色
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var baseColor = (_frameCounter + i / 3) % 256;
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imageData[i] = (byte)((baseColor + random.Next(0, 50)) % 256); // R
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imageData[i + 1] = (byte)((baseColor * 2 + random.Next(0, 50)) % 256); // G
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imageData[i + 2] = (byte)((baseColor * 3 + random.Next(0, 50)) % 256); // B
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}
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if (_frameCounter % 30 == 0) // 每秒更新一次日志
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{
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logger.Debug("生成第 {FrameNumber} 帧", _frameCounter);
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}
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return imageData;
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}
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/// <summary>
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/// 将 RGB 图像数据转换为 JPEG 格式
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/// </summary>
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private byte[] ConvertToJpeg(byte[] rgbData)
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{
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using var image = new Image<Rgb24>(_frameWidth, _frameHeight);
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// 将 RGB 数据复制到 ImageSharp 图像
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for (int y = 0; y < _frameHeight; y++)
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{
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for (int x = 0; x < _frameWidth; x++)
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{
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int index = (y * _frameWidth + x) * 3;
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var pixel = new Rgb24(rgbData[index], rgbData[index + 1], rgbData[index + 2]);
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image[x, y] = pixel;
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}
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}
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using var stream = new MemoryStream();
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image.SaveAsJpeg(stream, new JpegEncoder { Quality = 80 });
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return stream.ToArray();
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}
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/// <summary>
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/// 向所有连接的客户端广播帧数据
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/// </summary>
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private async Task BroadcastFrameAsync(byte[] frameData, CancellationToken cancellationToken)
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{
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if (frameData == null || frameData.Length == 0)
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{
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logger.Warn("尝试广播空帧数据");
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return;
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}
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// 准备MJPEG帧数据
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var mjpegFrameHeader = $"--boundary\r\nContent-Type: image/jpeg\r\nContent-Length: {frameData.Length}\r\n\r\n";
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var headerBytes = Encoding.ASCII.GetBytes(mjpegFrameHeader);
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var clientsToRemove = new List<HttpListenerResponse>();
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var clientsToProcess = new List<HttpListenerResponse>();
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// 获取当前连接的客户端列表
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lock (_clientsLock)
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{
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clientsToProcess.AddRange(_activeClients);
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}
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if (clientsToProcess.Count == 0)
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{
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return; // 没有活跃客户端
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}
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// 向每个活跃的客户端发送帧
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foreach (var client in clientsToProcess)
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{
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try
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{
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// 发送帧头部
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await client.OutputStream.WriteAsync(headerBytes, 0, headerBytes.Length, cancellationToken);
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// 发送JPEG数据
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await client.OutputStream.WriteAsync(frameData, 0, frameData.Length, cancellationToken);
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// 发送结尾换行符
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await client.OutputStream.WriteAsync(Encoding.ASCII.GetBytes("\r\n"), 0, 2, cancellationToken);
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// 确保数据立即发送
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await client.OutputStream.FlushAsync(cancellationToken);
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if (_frameCounter % 30 == 0) // 每秒记录一次日志
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{
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logger.Debug("已向客户端 {ClientId} 发送第 {FrameNumber} 帧，大小：{Size} 字节",
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client.OutputStream.GetHashCode(), _frameCounter, frameData.Length);
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}
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}
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catch (Exception ex)
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{
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logger.Debug("发送帧数据时出错: {Error}", ex.Message);
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clientsToRemove.Add(client);
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}
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}
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// 移除断开连接的客户端
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if (clientsToRemove.Count > 0)
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{
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lock (_clientsLock)
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{
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foreach (var client in clientsToRemove)
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{
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_activeClients.Remove(client);
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try { client.Close(); }
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catch { /* 忽略关闭错误 */ }
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}
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}
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logger.Info("已移除 {Count} 个断开连接的客户端，当前连接数: {ActiveCount}",
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clientsToRemove.Count, _activeClients.Count);
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}
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}
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/// <summary>
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/// 获取连接的客户端端点列表
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/// </summary>
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public List<string> GetConnectedClientEndpoints()
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{
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List<string> endpoints = new List<string>();
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lock (_clientsLock)
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{
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foreach (var client in _activeClients)
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{
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endpoints.Add($"Client-{client.OutputStream?.GetHashCode() ?? 0}");
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}
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}
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return endpoints;
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}
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/// <summary>
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/// 获取服务状态信息
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/// </summary>
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public object GetServiceStatus()
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{
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return new
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{
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IsRunning = _httpListener?.IsListening ?? false,
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ServerPort = _serverPort,
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FrameRate = _frameRate,
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Resolution = $"{_frameWidth}x{_frameHeight}",
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ConnectedClients = ConnectedClientsCount,
|
||
ClientEndpoints = GetConnectedClientEndpoints()
|
||
};
|
||
}
|
||
|
||
/// <summary>
|
||
/// 停止 HTTP 视频流服务
|
||
/// </summary>
|
||
public override async Task StopAsync(CancellationToken cancellationToken)
|
||
{
|
||
logger.Info("正在停止 HTTP 视频流服务...");
|
||
|
||
if (_httpListener != null && _httpListener.IsListening)
|
||
{
|
||
_httpListener.Stop();
|
||
_httpListener.Close();
|
||
}
|
||
|
||
// 关闭所有客户端连接
|
||
lock (_clientsLock)
|
||
{
|
||
foreach (var client in _activeClients)
|
||
{
|
||
try { client.Close(); }
|
||
catch { /* 忽略关闭错误 */ }
|
||
}
|
||
_activeClients.Clear();
|
||
}
|
||
|
||
await base.StopAsync(cancellationToken);
|
||
|
||
logger.Info("HTTP 视频流服务已停止");
|
||
}
|
||
|
||
/// <summary>
|
||
/// 释放资源
|
||
/// </summary>
|
||
public override void Dispose()
|
||
{
|
||
if (_httpListener != null)
|
||
{
|
||
if (_httpListener.IsListening)
|
||
{
|
||
_httpListener.Stop();
|
||
}
|
||
_httpListener.Close();
|
||
}
|
||
|
||
lock (_clientsLock)
|
||
{
|
||
foreach (var client in _activeClients)
|
||
{
|
||
try { client.Close(); }
|
||
catch { /* 忽略关闭错误 */ }
|
||
}
|
||
_activeClients.Clear();
|
||
}
|
||
|
||
base.Dispose();
|
||
}
|
||
}
|