390 lines
15 KiB
C#
390 lines
15 KiB
C#
using System;
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using System.Collections.Concurrent;
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using System.Diagnostics;
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using System.Threading.Tasks;
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using NetMQ;
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using NetMQ.Sockets;
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using Newtonsoft.Json;
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using SHH.Contracts;
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namespace SHH.CameraDashboard.Services
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{
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/// <summary>
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/// 客户端指令总线 (企业增强版)
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/// <para>核心职责：作为指挥中心监听 7000 端口，管理所有网关连接。</para>
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/// <para>通讯模式：Router (Bind) <--- Dealer (Connect)</para>
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/// <para>高级特性：</para>
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/// <para>1. 智能路由：根据 InstanceId 自动查找 NetMQ Identity。</para>
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/// <para>2. QoS 分级：支持 "强一致性等待" 和 "射后不理" 两种模式。</para>
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/// <para>3. 自动重试：网络超时自动重发，失败多次自动熔断。</para>
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/// <para>4. 性能监控：精确统计全链路耗时 (RTT)。</para>
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/// </summary>
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public class CommandBusClient : IDisposable
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{
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#region --- 1. 字段与配置 ---
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private RouterSocket? _routerSocket;
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private NetMQPoller? _poller;
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private volatile bool _isRunning;
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private readonly object _disposeLock = new object();
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// 默认超时设置
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private const int DEFAULT_TIMEOUT_MS = 2000;
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private const int DEFAULT_MAX_RETRIES = 2;
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// ★★★ 核心：线程安全的任务字典 <RequestId, TCS> ★★★
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// Key: 请求ID (身份证号)
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// Value: 异步任务凭证 (用于 await 唤醒)
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private readonly ConcurrentDictionary<string, TaskCompletionSource<CommandResult>> _pendingRequests
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= new ConcurrentDictionary<string, TaskCompletionSource<CommandResult>>();
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// ★★★ 核心：路由表 ★★★
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// Key: 实例ID (例如 "Gateway_01")
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// Value: NetMQ 路由 Identity (二进制地址，这是 Router 发消息必须的“信封地址”)
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private readonly ConcurrentDictionary<string, byte[]> _sessions
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= new ConcurrentDictionary<string, byte[]>();
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/// <summary>
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/// 当有服务端连上来并完成注册时触发
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/// </summary>
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public event Action<ServerRegistrationDto>? OnServerRegistered;
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#endregion
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#region --- 2. 启动与停止 ---
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/// <summary>
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/// 启动指令中心监听
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/// </summary>
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/// <param name="port">监听端口 (建议 7000)</param>
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public void Start(int port)
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{
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if (_isRunning) return;
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try
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{
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lock (_disposeLock)
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{
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_routerSocket = new RouterSocket();
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// 绑定端口，等待服务端(Active Mode)主动来连接
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// 使用 tcp://*:{port} 绑定本机所有网卡
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_routerSocket.Bind($"tcp://*:{port}");
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// 注册接收事件 (基于 NetMQPoller 的异步非阻塞模式)
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_routerSocket.ReceiveReady += OnReceiveReady;
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_poller = new NetMQPoller { _routerSocket };
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_poller.RunAsync(); // 在后台线程启动轮询
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_isRunning = true;
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Debug.WriteLine($"[ClientBus] 指令中心已启动，监听端口: {port}");
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}
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}
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catch (Exception ex)
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{
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// 启动失败属于致命错误，记录日志
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Debug.WriteLine($"[ClientBus-Error] 启动失败: {ex.Message}");
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throw; // 向上抛出，让 UI 层感知并报错
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}
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}
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public void Stop()
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{
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if (!_isRunning) return;
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lock (_disposeLock)
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{
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_isRunning = false;
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try
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{
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_poller?.Stop();
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_poller?.Dispose();
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_routerSocket?.Dispose();
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}
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catch (Exception ex)
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{
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Debug.WriteLine($"[ClientBus-Error] 停止时异常: {ex.Message}");
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}
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finally
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{
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// 彻底清理状态
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CleanupPendingTasks();
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_sessions.Clear();
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}
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}
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}
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public void Dispose()
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{
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Stop();
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}
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private void CleanupPendingTasks()
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{
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// 取消所有挂起的请求，避免 SendAsync 里的 await 永久卡死
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foreach (var kvp in _pendingRequests)
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{
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kvp.Value.TrySetCanceled();
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}
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_pendingRequests.Clear();
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}
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#endregion
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#region --- 3. 核心发送逻辑 (策略层) ---
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/// <summary>
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/// 发送指令（包含 QoS判断 + 重试循环 + 熔断 + RTT统计）
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/// </summary>
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/// <param name="instanceId">目标网关ID (如 "Gateway_01")</param>
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/// <param name="payload">指令包</param>
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/// <param name="timeoutMs">单次超时时间 (毫秒)</param>
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/// <param name="maxRetries">最大重试次数 (0表示不重试)</param>
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/// <returns>执行结果</returns>
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public async Task<CommandResult> SendAsync(string instanceId, CommandPayload payload, int timeoutMs = DEFAULT_TIMEOUT_MS, int maxRetries = DEFAULT_MAX_RETRIES)
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{
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if (!_isRunning) return CommandResult.Fail("服务未启动");
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// 1. 检查目标是否在线 (快速失败)
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if (!_sessions.ContainsKey(instanceId))
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{
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return CommandResult.Fail($"服务端 {instanceId} 离线或未连接");
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}
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// 2. 确保有 RequestId
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if (string.IsNullOrEmpty(payload.RequestId))
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payload.RequestId = Guid.NewGuid().ToString("N");
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// =========================================================
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// 策略 A: 射后不理 (Fire-and-Forget) - QoS 0
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// =========================================================
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// 适用于：心跳包、非关键日志、高频状态查询
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// 优势：不占用 await 线程资源，不产生网络拥堵
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if (!payload.RequireAck)
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{
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try
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{
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SendInternal(instanceId, payload);
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return CommandResult.Ok("已投递 (NoAck Mode)");
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}
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catch (Exception ex)
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{
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return CommandResult.Fail($"投递失败: {ex.Message}");
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}
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}
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// =========================================================
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// 策略 B: 强一致性重试 (Reliable Retry) - QoS 1
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// =========================================================
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// 适用于：PTZ控制、录像启停、参数设置
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int currentRetry = 0;
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// 启动高精度计时器 (统计包含重试在内的总耗时)
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Stopwatch totalStopwatch = Stopwatch.StartNew();
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// 重试循环 (Retry Loop)
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while (currentRetry <= maxRetries)
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{
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// 更新重试计数，服务端可据此判断是否需要打印 "Retry Warning"
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payload.RetryCount = currentRetry;
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try
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{
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// ★ 核心原子操作：发送并等待单次结果 ★
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var result = await SendRequestCore(instanceId, payload, timeoutMs);
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// --- 成功路径 ---
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totalStopwatch.Stop();
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result.ElapsedMilliseconds = totalStopwatch.Elapsed.TotalMilliseconds;
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// 如果重试过，打印一条恢复日志
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if (currentRetry > 0)
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Debug.WriteLine($"[ClientBus] {payload.CmdCode} 在第 {currentRetry} 次重试后成功恢复。");
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return result;
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}
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catch (TimeoutException)
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{
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// --- 超时路径 ---
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Debug.WriteLine($"[ClientBus-Warn] Req {payload.RequestId} 超时 ({currentRetry + 1}/{maxRetries + 1})...");
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currentRetry++;
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// 可选：在重试前稍微等待一下 (指数退避)，避免瞬间拥塞
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// await Task.Delay(50 * currentRetry);
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}
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catch (Exception ex)
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{
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// --- 致命错误路径 (如序列化失败、Socket已释放) ---
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// 这种错误重试也没用，直接报错
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return CommandResult.Fail($"发送过程发生不可恢复错误: {ex.Message}");
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}
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}
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// =========================================================
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// 熔断 (Meltdown)
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// =========================================================
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totalStopwatch.Stop();
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var failRes = CommandResult.Fail($"请求熔断: 目标无响应 (已重试 {maxRetries} 次)");
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failRes.ElapsedMilliseconds = totalStopwatch.Elapsed.TotalMilliseconds;
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return failRes;
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}
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#endregion
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#region --- 4. 底层发送实现 (原子操作层) ---
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/// <summary>
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/// 执行单次 "请求-响应" 周期
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/// </summary>
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private async Task<CommandResult> SendRequestCore(string instanceId, CommandPayload payload, int timeoutMs)
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{
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// 1. 创建异步凭证 (TCS)
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// RunContinuationsAsynchronously 是必须的，防止 NetMQ 接收线程直接执行 await 后的 UI 代码导致死锁
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var tcs = new TaskCompletionSource<CommandResult>(TaskCreationOptions.RunContinuationsAsynchronously);
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// 2. 注册到字典，等待回信
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// 如果 ID 冲突 (极低概率)，说明上一个还没处理完，强行覆盖或报错
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_pendingRequests[payload.RequestId] = tcs;
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try
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{
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// 3. 发送网络包
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SendInternal(instanceId, payload);
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// 4. 异步等待 (Wait for TCS or Timeout)
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// Task.WhenAny 是实现超时的经典模式
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var completedTask = await Task.WhenAny(tcs.Task, Task.Delay(timeoutMs));
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if (completedTask == tcs.Task)
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{
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// 任务完成 (OnReceiveReady 设置了结果)
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return await tcs.Task;
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}
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else
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{
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// 时间到，任务还没完成 -> 抛出超时异常，触发外层重试
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throw new TimeoutException();
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}
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}
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finally
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{
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// 5. 清理现场 (无论成功失败，必须移除字典，防止内存泄漏)
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_pendingRequests.TryRemove(payload.RequestId, out _);
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}
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}
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/// <summary>
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/// 纯粹的 NetMQ 数据发送 (不处理逻辑)
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/// </summary>
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private void SendInternal(string instanceId, CommandPayload payload)
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{
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// 查路由表获取 Identity
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if (_sessions.TryGetValue(instanceId, out byte[]? identity))
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{
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var msg = new NetMQMessage();
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// Frame 1: 目标地址 (Identity)
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msg.Append(identity);
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// Frame 2: 数据 (JSON)
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msg.Append(JsonConvert.SerializeObject(payload));
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// 线程安全检查
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if (_routerSocket != null)
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{
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_routerSocket.SendMultipartMessage(msg);
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}
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}
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else
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{
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throw new InvalidOperationException($"无法找到目标 {instanceId} 的路由信息");
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}
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}
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#endregion
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#region --- 5. 核心接收逻辑 (Router) ---
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/// <summary>
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/// 处理所有入站消息
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/// </summary>
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private void OnReceiveReady(object? sender, NetMQSocketEventArgs e)
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{
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// 防止处理过程中崩溃导致监听停止
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try
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{
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NetMQMessage msg = new NetMQMessage();
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// Router 模式：至少包含 [Identity, Data] 两帧，有时中间会有空帧
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if (!e.Socket.TryReceiveMultipartMessage(ref msg) || msg.FrameCount < 2) return;
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// 第一帧永远是发送方的 Identity
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byte[] identity = msg[0].Buffer;
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// 最后一帧通常是 JSON 数据
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string json = msg.Last.ConvertToString();
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// 简单的协议识别
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// 优化建议：正式项目中可以用更严谨的 Header 区分，这里用 JSON 嗅探即可
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if (json.Contains("\"CmdCode\""))
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{
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// ---> 收到注册包 (CmdCode 字段存在)
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HandleRegistration(identity, json);
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}
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else if (json.Contains("\"Success\""))
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{
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// ---> 收到回执包 (Success 字段存在)
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HandleResponse(json);
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}
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}
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catch (Exception ex)
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{
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Debug.WriteLine($"[ClientBus-RecvError] 接收处理异常: {ex.Message}");
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}
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}
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private void HandleRegistration(byte[] identity, string json)
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{
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try
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{
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var payload = JsonConvert.DeserializeObject<CommandPayload>(json);
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if (payload?.CmdCode == "SERVER_REGISTER")
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{
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var regInfo = JsonConvert.DeserializeObject<ServerRegistrationDto>(payload.JsonParams);
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if (regInfo != null)
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{
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// 更新路由表：[实例名] -> [二进制地址]
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_sessions[regInfo.InstanceId] = identity;
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Debug.WriteLine($"[ClientBus] 网关上线: {regInfo.InstanceId} IP: {regInfo.ServerIp}");
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// 通知 UI 刷新列表
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OnServerRegistered?.Invoke(regInfo);
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}
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}
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}
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catch (Exception ex)
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{
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Debug.WriteLine($"[ClientBus-Warn] 注册包解析失败: {ex.Message}");
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}
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}
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private void HandleResponse(string json)
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{
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try
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{
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var result = JsonConvert.DeserializeObject<CommandResult>(json);
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// 闭环匹配：根据 RequestId 找到挂起的 TCS
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if (!string.IsNullOrEmpty(result?.RequestId) &&
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_pendingRequests.TryGetValue(result.RequestId, out var tcs))
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{
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// 设置结果 -> 唤醒 SendRequestCore -> 唤醒 SendAsync
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tcs.TrySetResult(result);
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}
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}
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catch (Exception ex)
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{
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Debug.WriteLine($"[ClientBus-Warn] 回执包解析失败: {ex.Message}");
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}
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}
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#endregion
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}
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} |