using System.Net.Sockets;
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using System.Text;
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using System.Text.Json;
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using System.IO;
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namespace WIDESEAWCS_Tasks.SocketServer
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{
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public partial class TcpSocketServer
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{
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/// <summary>
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/// 处理客户端连接的消息循环
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/// </summary>
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/// <remarks>
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/// 持续接收客户端消息，直到连接断开或取消。
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/// 处理流程：
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/// 1. 接收消息（帧解析）
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/// 2. 更新客户端状态（活跃时间、编码）
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/// 3. 处理设备注册
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/// 4. 触发 MessageReceived 事件
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/// 连接断开时清理资源并触发 RobotReceived 事件。
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/// </remarks>
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/// <param name="client">TCP 客户端连接</param>
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/// <param name="clientId">客户端唯一标识</param>
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/// <param name="cancellationToken">取消令牌</param>
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/// <param name="robotCrane">机器人状态</param>
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public async Task HandleClientAsync(TcpClient client, string clientId, CancellationToken cancellationToken, RobotSocketState robotCrane)
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{
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using (client)
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using (NetworkStream networkStream = client.GetStream())
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using (StreamReader reader = new(networkStream, _textEncoding, false, 1024, true))
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using (StreamWriter writer = new(networkStream, _textEncoding, 1024, true) { AutoFlush = true })
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{
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CancellationTokenSource? localCts = null;
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if (_options.EnableHeartbeat || _options.IdleTimeoutSeconds > 0)
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{
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// 创建链接的取消令牌源
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localCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
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}
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try
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{
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// 消息接收循环
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while (!cancellationToken.IsCancellationRequested && client.Connected)
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{
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string? message;
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try
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{
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var ct = localCts?.Token ?? cancellationToken;
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// 接收完整消息（帧解析）
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message = await ReceiveFullMessageAsync(networkStream, _textEncoding, ct);
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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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if (message == null)
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{
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break;
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}
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// 更新客户端状态
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UpdateClientStatus(clientId, message);
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string messageLower = message.ToLowerInvariant();
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// 处理注册消息
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if (TryHandleRegister(messageLower, message, clientId, networkStream, cancellationToken))
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{
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continue;
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}
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// 触发消息接收事件
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if (MessageReceived != null)
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{
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try
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{
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// 判断是否为 JSON 格式
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bool isJsonFormat = TryParseJsonSilent(message);
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_ = MessageReceived.Invoke(message, isJsonFormat, client, robotCrane);
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}
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catch { }
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}
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}
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}
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finally
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{
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// 清理资源
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try { localCts?.Cancel(); localCts?.Dispose(); } catch { }
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RemoveClient(clientId);
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try { _ = RobotReceived.Invoke(clientId); } catch { }
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}
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}
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}
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/// <summary>
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/// 处理设备注册消息
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/// </summary>
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/// <remarks>
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/// 注册消息格式：register,{deviceId}
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/// 将设备 ID 绑定到当前客户端 ID。
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/// </remarks>
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/// <param name="messageLower">消息小写版本</param>
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/// <param name="message">原始消息</param>
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/// <param name="clientId">客户端 ID</param>
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/// <param name="networkStream">网络流</param>
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/// <param name="cancellationToken">取消令牌</param>
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/// <returns>是否处理了注册消息</returns>
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private bool TryHandleRegister(string messageLower, string message, string clientId, NetworkStream networkStream, CancellationToken cancellationToken)
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{
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if (!messageLower.StartsWith("register,"))
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{
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return false;
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}
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// 提取设备 ID
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string deviceId = message.Substring("register,".Length).Trim();
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if (!string.IsNullOrEmpty(deviceId))
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{
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lock (_syncRoot)
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{
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// 绑定设备到客户端
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_deviceBindings[deviceId] = clientId;
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}
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// 回复注册成功
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_ = WriteToClientAsync(clientId, networkStream, $"Registered,{deviceId}", cancellationToken);
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}
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return true;
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}
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/// <summary>
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/// 更新客户端状态
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/// </summary>
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/// <remarks>
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/// 更新最后活跃时间和字符编码。
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/// 如果开启了自动编码检测，根据消息内容判断是 UTF-8 还是 GBK。
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/// </remarks>
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/// <param name="clientId">客户端 ID</param>
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/// <param name="message">最新接收的消息</param>
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private void UpdateClientStatus(string clientId, string message)
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{
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lock (_syncRoot)
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{
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// 更新最后活跃时间
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_clientLastActive[clientId] = DateTime.Now;
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// 如果还没有记录编码
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if (!_clientEncodings.ContainsKey(clientId))
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{
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if (_options.AutoDetectEncoding && _autoDetectedGb2312 != null)
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{
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// 自动检测编码：JSON 或 UTF-8 字节特征则用 UTF-8，否则用 GBK
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bool isUtf8 = TryParseJsonSilent(message) || IsLikelyUtf8(_textEncoding.GetBytes(message));
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_clientEncodings[clientId] = isUtf8 ? _textEncoding : _autoDetectedGb2312;
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}
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else
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{
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_clientEncodings[clientId] = _textEncoding;
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}
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}
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}
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}
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/// <summary>
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/// 异步发送消息到客户端
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/// </summary>
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/// <remarks>
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/// 内部方法，不使用帧格式，直接发送原始消息。
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/// </remarks>
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private async Task WriteToClientAsync(string clientId, NetworkStream networkStream, string message, CancellationToken cancellationToken)
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{
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SemaphoreSlim? sem = null;
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Encoding? enc = null;
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lock (_syncRoot)
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{
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_clientLocks.TryGetValue(clientId, out sem);
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_clientEncodings.TryGetValue(clientId, out enc);
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}
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enc ??= _textEncoding;
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if (sem != null) await sem.WaitAsync(cancellationToken);
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try
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{
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var framedMessage = BuildFramedMessage(message);
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var data = enc.GetBytes(framedMessage);
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await networkStream.WriteAsync(data, 0, data.Length, cancellationToken);
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}
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finally
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{
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if (sem != null) sem.Release();
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}
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}
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/// <summary>
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/// 构建帧消息
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/// </summary>
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/// <remarks>
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/// 在消息前后添加头尾标识。
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/// </remarks>
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/// <param name="message">原始消息</param>
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/// <returns>带帧标识的消息</returns>
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private string BuildFramedMessage(string message)
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{
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var header = _options.MessageHeader ?? string.Empty;
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var footer = _options.MessageFooter ?? string.Empty;
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return header + (message ?? string.Empty) + footer;
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}
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/// <summary>
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/// 静默尝试解析 JSON
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/// </summary>
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/// <remarks>
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/// 判断消息是否以 { 或 [ 开头，如果是则尝试解析。
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/// 解析失败不抛异常。
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/// </remarks>
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/// <param name="message">消息内容</param>
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/// <returns>是否是有效的 JSON 格式</returns>
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private static bool TryParseJsonSilent(string message)
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{
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if (string.IsNullOrWhiteSpace(message)) return false;
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char c = message.TrimStart()[0];
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if (c != '{' && c != '[') return false;
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try { JsonDocument.Parse(message); return true; } catch { return false; }
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}
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/// <summary>
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/// 判断字节数组是否为 UTF-8 编码
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/// </summary>
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/// <remarks>
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/// 通过检查字节序列是否符合 UTF-8 多字节字符的编码规则。
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/// </remarks>
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/// <param name="data">字节数组</param>
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/// <returns>是否可能是 UTF-8 编码</returns>
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private static bool IsLikelyUtf8(byte[] data)
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{
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int i = 0;
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while (i < data.Length)
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{
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byte b = data[i];
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if (b <= 0x7F) { i++; continue; } // ASCII 字符
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// 检查多字节字符
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if (b >= 0xC2 && b <= 0xDF) // 2字节字符
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{
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if (i + 1 >= data.Length) return false;
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if ((data[i + 1] & 0xC0) != 0x80) return false;
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i += 2; continue;
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}
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if (b >= 0xE0 && b <= 0xEF) // 3字节字符
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{
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if (i + 2 >= data.Length) return false;
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if ((data[i + 1] & 0xC0) != 0x80 || (data[i + 2] & 0xC0) != 0x80) return false;
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i += 3; continue;
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}
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if (b >= 0xF0 && b <= 0xF4) // 4字节字符
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{
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if (i + 3 >= data.Length) return false;
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if ((data[i + 1] & 0xC0) != 0x80 || (data[i + 2] & 0xC0) != 0x80 || (data[i + 3] & 0xC0) != 0x80) return false;
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i += 4; continue;
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}
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return false;
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}
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return true;
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}
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/// <summary>
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/// 接收完整消息（帧解析）
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/// </summary>
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/// <remarks>
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/// 根据配置的头尾标识解析消息。
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/// 如果未配置头尾，则一直读到数据不可用。
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/// </remarks>
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/// <param name="networkStream">网络流</param>
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/// <param name="encoding">字符编码</param>
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/// <param name="cancellationToken">取消令牌</param>
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/// <returns>接收到的消息</returns>
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private async Task<string?> ReceiveFullMessageAsync(NetworkStream networkStream, Encoding encoding, CancellationToken cancellationToken)
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{
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var header = _options.MessageHeader ?? string.Empty;
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var footer = _options.MessageFooter ?? string.Empty;
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var buffer = new byte[1024];
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var builder = new StringBuilder();
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while (true)
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{
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// 读取数据
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int bytesRead = await networkStream.ReadAsync(buffer.AsMemory(0, buffer.Length), cancellationToken);
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if (bytesRead <= 0)
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{
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if (builder.Length == 0) return null;
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// 无头尾配置时，返回已有数据
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return string.IsNullOrEmpty(header) && string.IsNullOrEmpty(footer) ? builder.ToString() : null;
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}
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builder.Append(encoding.GetString(buffer, 0, bytesRead));
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// 如果没有配置头尾，且数据不可用，返回已有数据
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if (string.IsNullOrEmpty(header) && string.IsNullOrEmpty(footer))
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{
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if (!networkStream.DataAvailable)
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{
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break;
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}
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continue;
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}
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// 查找帧头
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var data = builder.ToString();
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var headerIndex = string.IsNullOrEmpty(header) ? 0 : data.IndexOf(header, StringComparison.Ordinal);
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if (headerIndex < 0)
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{
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continue;
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}
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// 提取帧内容
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var startIndex = headerIndex + header.Length;
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var footerIndex = string.IsNullOrEmpty(footer) ? data.Length : data.IndexOf(footer, startIndex, StringComparison.Ordinal);
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if (footerIndex >= 0)
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{
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return data.Substring(startIndex, footerIndex - startIndex);
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}
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}
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return builder.ToString();
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}
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}
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}
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