YD_YiLu.Api/YD_YiLu/WebSockets/ICameraDeviceSocketRegistry.cs

using System.Collections.Concurrent;
using System.Net.WebSockets;

namespace YD_YiLu.Api.WebSockets
{
    public class DeviceConnection
    {
        public WebSocket Socket { get; set; } = default!;
        public DateTime LastHeartbeat { get; set; } = DateTime.Now;
    }

    public interface ICameraDeviceSocketRegistry
    {
        void Register(string serialNumber, WebSocket socket);
        void Unregister(string serialNumber);
        bool TryGet(string serialNumber, out WebSocket socket);

        void UpdateHeartbeat(string serialNumber);
        List<string> GetTimeoutDevices(TimeSpan timeout);
    }

    public class CameraDeviceSocketRegistry : ICameraDeviceSocketRegistry
    {
        private readonly ConcurrentDictionary<string, DeviceConnection> _connections
            = new(StringComparer.OrdinalIgnoreCase);

        public void Register(string serialNumber, WebSocket socket)
        {
            _connections[serialNumber] = new DeviceConnection
            {
                Socket = socket,
                LastHeartbeat = DateTime.Now
            };
        }

        public void Unregister(string serialNumber)
        {
            _connections.TryRemove(serialNumber, out _);
        }

        public bool TryGet(string serialNumber, out WebSocket socket)
        {
            if (_connections.TryGetValue(serialNumber, out var conn))
            {
                socket = conn.Socket;
                return true;
            }
            socket = null!;
            return false;
        }

        public void UpdateHeartbeat(string serialNumber)
        {
            if (_connections.TryGetValue(serialNumber, out var conn))
            {
                conn.LastHeartbeat = DateTime.Now;
            }
        }

        public List<string> GetTimeoutDevices(TimeSpan timeout)
        {
            var now = DateTime.Now;

            return _connections
                .Where(x => now - x.Value.LastHeartbeat > timeout)
                .Select(x => x.Key)
                .ToList();
        }
    }
}