ASP.NETCore+SignalR实现基础实时通讯系统（完整实战）

从零实现一个 ASP.NET Core SignalR 实时聊天系统

声明，这是一篇关于 SignalR 的基础文章，仅涉及 SignalR 的基础功能，例如 JWT 、 及 webscoket 的限流，这部分则另外开一篇文章（项目已经完成了，但还没想好怎么写）。

在传统 Web 应用中，客户端与服务器之间通常通过 HTTP 请求进行通信。这种通信模式是 请求-响应（Request-Response） 的，即客户端必须先发送请求，服务器才能返回数据。

然而，在很多现代应用场景中，这种模式并不够用，例如：

  • 实时聊天

  • 在线协作编辑

  • 实时通知系统

  • 在线游戏

  • 实时数据监控

这些应用都需要 服务器能够主动向客户端推送消息。

在 ASP.NET Core 生态中，微软提供了一个官方解决方案 —— SignalR。

本文将介绍 如何使用 ASP.NET Core + SignalR 构建一个实时聊天系统，并介绍 SignalR 的核心概念与基本使用方式。

因为我这个实验我做的是前后端分离，所以就涉及到跨域。

为了方便，我就在后端跨域设置允许所有源

拓展类（允许所有源）

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using Microsoft.OpenApi.Models;
namespace SignalRAspNetCoreTest01x02.Extensions
{
    public static class AllowAllCoreExtensions
    {
        public static IServiceCollection AddAllowAllCors(this IServiceCollection services) 
        {
            services.AddCors(options =>
            {
                options.AddPolicy("AllowAll", builder =>
                {
                    //builder.AllowAnyOrigin()
                    //       .AllowAnyMethod()
                    //       .AllowAnyHeader()
                    //       .AllowCredentials();
                    builder.SetIsOriginAllowed(_ => true) // 允许任何来源
                          .AllowAnyMethod()
                          .AllowAnyHeader()
                          //.WithOrigins("*")
                          //.WithOrigins("http://localhost:xxxx")
                          .AllowCredentials();
                });
            });
            return services;
        }
    }
}

再添加一个关于Swagger-JWT的拓展类,现在暂时不需要，但为后面的升级留下空间。

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using Microsoft.Extensions.DependencyInjection;
using Microsoft.OpenApi.Models;

namespace SignalRAspNetCoreTest01x02.Extensions
{
    public static class SwaggerExtensions
    {
        public static IServiceCollection AddSwaggerWithJwt(
            this IServiceCollection services)
        {
            services.AddSwaggerGen(options =>
            {
                // 添加 JWT Bearer 定义
                options.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme
                {
                    Name = "Authorization",
                    Type = SecuritySchemeType.Http,
                    Scheme = "bearer",
                    BearerFormat = "JWT",
                    In = ParameterLocation.Header,
                    Description = "输入：token"
                });

                // 添加全局安全要求
                options.AddSecurityRequirement(new OpenApiSecurityRequirement
                {
                    {
                        new OpenApiSecurityScheme
                        {
                            Reference = new OpenApiReference
                            {
                                Type = ReferenceType.SecurityScheme,
                                Id = "Bearer"
                            }
                        },
                        new string[] {}
                    }
                });
            });

            return services;
        }
    }
}

在 program.cs 中使用拓展类

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builder.Services.AddSwaggerWithJwt();

//允许跨域（拓展）
builder.Services.AddAllowAllCors();

app.MapControllers();

app.UseCors("AllowAll");

小要点 AddSwaggerWithJwt 来自拓展类的

public static IServiceCollection AddSwaggerWithJwt(this IServiceCollection services)

在开始正式内容之前先安装相关的包：Microsoft.AspNetCore.SignalR

一、什么是 SignalR

ASP.NET Core SignalR 是微软提供的一个实时通信库，用于简化服务器与客户端之间的实时通信。

SignalR 的核心特点包括：

  • 支持服务器主动推送消息

  • 自动选择最佳传输协议

  • 简化 WebSocket 开发

  • 与 ASP.NET Core 深度集成

SignalR 在底层会自动选择最佳通信方式：

    1. WebSocket（优先）
    1. Server-Sent Events
    1. Long Polling

开发者无需关心具体实现，SignalR 会自动处理协议降级问题。

二、SignalR 的核心概念

在使用 SignalR 之前，需要理解几个核心概念。

1 Hub

Hub 是 SignalR 的核心组件。

Hub 类似于一个 通信中心，负责处理客户端与服务器之间的消息交互。

客户端可以调用 Hub 中的方法，而服务器也可以通过 Hub 向客户端发送消息。

创建一个 Hub：

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using Microsoft.AspNetCore.SignalR;
using SignalRAspNetCoreTest01x02.Contracts;
using SignalRAspNetCoreTest01x02.Services;

namespace SignalRAspNetCoreTest01x02.Hubs
{
    public class ChatHub : Hub
    {
        private readonly ConnectionManager _registry;
        public ChatHub(ConnectionManager registry) => _registry = registry;

        //确保每条消息都有 Timestamp
        private void EnsureTimestamp(MessageDto msg)
        {
            if (string.IsNullOrEmpty(msg.Timestamp))
                msg.Timestamp = DateTime.UtcNow.ToString("O"); // ISO 8601
        }

        public override Task OnConnectedAsync()
        {
            var userId = Context.GetHttpContext()?.Request.Query["userId"];
            if (!string.IsNullOrEmpty(userId))
                _registry.AddConnection(userId!, Context.ConnectionId);

            // 告诉客户端当前 ConnectionId
            Clients.Caller.SendAsync("ConnectionAck", Context.ConnectionId);
            return base.OnConnectedAsync();
        }

        public override Task OnDisconnectedAsync(Exception? ex)
        {
            _registry.RemoveConnection(Context.ConnectionId);
            return base.OnDisconnectedAsync(ex);
        }

        // 广播消息
        public Task BroadcastMessage(MessageDto msg)
        {
            EnsureTimestamp(msg);
            return Clients.All.SendAsync("ReceiveMessage", msg);
        }

        // 单发消息
        public Task SendMessageToUser(string targetConnectionId, MessageDto msg)
        {
            EnsureTimestamp(msg);
            return Clients.Client(targetConnectionId).SendAsync("ReceiveMessage", msg);
        }

        // 加入组
        public Task JoinGroup(string groupName) => Groups.AddToGroupAsync(Context.ConnectionId, groupName);
        
        // 退出组
        public Task LeaveGroup(string groupName)
        {
            return Groups.RemoveFromGroupAsync(Context.ConnectionId, groupName);
        }
        // 向组发送消息
        public Task SendMessageToGroup(string groupName, MessageDto msg)
        {
            EnsureTimestamp(msg);
            return Clients.Group(groupName).SendAsync("ReceiveMessage", msg);
        }
    }
}

在这个 Hub 中，客户端可以调用 BroadcastMessage 方法，而服务器会将消息广播给所有客户端。

创建一个消息体，统一传输消息的结构

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namespace SignalRAspNetCoreTest01x02.Contracts
{
    /// <summary>
    /// SignalR 消息数据传输对象
    /// </summary>
    public class MessageDto
    {
        /// <summary>
        /// 消息发送人
        /// </summary>
        public string Sender { get; set; } = string.Empty;

        /// <summary>
        /// 私聊接收人ID（私聊时使用）
        /// </summary>
        public string? Receiver { get; set; } = string.Empty;

        /// <summary>
        /// 消息内容
        /// </summary>
        public string Content { get; set; } = string.Empty;

        /// <summary>
        /// 消息时间戳（UTC 字符串）
        /// </summary>
        public string Timestamp { get; set; } = DateTime.UtcNow.ToString("O"); // ISO 8601 字符串

        /// <summary>
        /// 可选：消息类型，比如 "chat" / "system" / "notification"
        /// </summary>
        public string? MessageType { get; set; } = string.Empty;

        /// <summary>
        /// 可选：分组或房间
        /// </summary>
        public string? Group { get; set; } = string.Empty;
    }
}

添加一个管理类,为升级留出空间

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using System.Collections.Concurrent;
namespace SignalRAspNetCoreTest01x02.Services
{
    public class ConnectionManager
    {
        // userId -> connectionId
        private readonly ConcurrentDictionary<string, string> _userConnections = new();

        public void AddConnection(string userId, string connectionId)
        {
            _userConnections[userId] = connectionId;
        }

        public void RemoveConnection(string connectionId)
        {
            var user = _userConnections.FirstOrDefault(x => x.Value == connectionId);
            if (!string.IsNullOrEmpty(user.Key))
            {
                _userConnections.TryRemove(user.Key, out _);
            }
        }

        public string? GetConnection(string userId)
        {
            return _userConnections.TryGetValue(userId, out var connId)
                ? connId
                : null;
        }
    }
}

在 program.cs 中注册 SignalR 、 及管理类（注意生命周期）

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//添加SignalR
builder.Services.AddSignalR();

// 连接管理单例
builder.Services.AddSingleton<ConnectionManager>();

//添加映射
app.MapHub<ChatHub>("/chatHub");

结束。GitHub 地址：https://github.com/lxy1234cn/SignalRAspNetCoreTest01x02

完整 program.cs

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using SignalRAspNetCoreTest01x02.Extensions;
using SignalRAspNetCoreTest01x02.Hubs;
using SignalRAspNetCoreTest01x02.Services;
var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();

//builder.Services.AddSwaggerGen();
//添加Swagger并配置JWT（拓展）
builder.Services.AddSwaggerWithJwt();

//允许跨域（拓展）
builder.Services.AddAllowAllCors();

//添加SignalR
builder.Services.AddSignalR();

// 连接管理单例
builder.Services.AddSingleton<ConnectionManager>();

var app = builder.Build();

// Configure the HTTP request pipeline.
//if (app.Environment.IsDevelopment())
//{
    app.UseSwagger();
    app.UseSwaggerUI();
//}

app.UseHttpsRedirection();

app.UseAuthorization();

app.MapGet("/", () => "Hello! " + DateTime.Now.ToString("HH:mm:ss.fff"));

app.MapControllers();

app.UseCors("AllowAll");

app.MapHub<ChatHub>("/chatHub");

app.Run();

前端html

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<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>SignalR 多分区聊天</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/microsoft-signalr/8.0.0/signalr.min.js"></script>
<style>
  *,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
  :root{
    --bg-primary:#0a0a0b;
    --bg-secondary:#111113;
    --bg-tertiary:#1a1a1d;
    --bg-hover:#222226;
    --bg-active:#2a2a2f;
    --border:#2a2a2e;
    --border-light:#333338;
    --text-primary:#ededef;
    --text-secondary:#a0a0a8;
    --text-muted:#6b6b74;
    --accent:#3b82f6;
    --accent-hover:#2563eb;
    --accent-soft:rgba(59,130,246,0.12);
    --green:#22c55e;
    --green-soft:rgba(34,197,94,0.12);
    --orange:#f59e0b;
    --orange-soft:rgba(245,158,11,0.12);
    --red:#ef4444;
    --red-soft:rgba(239,68,68,0.12);
    --bubble-self:#1d4ed8;
    --bubble-other:#1f1f23;
    --radius:10px;
    --radius-sm:6px;
    --radius-lg:14px;
    --shadow:0 2px 8px rgba(0,0,0,0.3);
    --transition:all 0.2s ease;
  }
  html,body{
    height:100%;
    font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
    background:var(--bg-primary);
    color:var(--text-primary);
    overflow:hidden;
  }

  /* ===== Layout ===== */
  .app{display:flex;height:100vh;width:100%;}

  /* ===== Sidebar ===== */
  .sidebar{
    width:280px;
    min-width:280px;
    background:var(--bg-secondary);
    border-right:1px solid var(--border);
    display:flex;
    flex-direction:column;
    overflow:hidden;
  }
  .sidebar-header{
    padding:20px;
    border-bottom:1px solid var(--border);
  }
  .sidebar-header h2{
    font-size:16px;
    font-weight:600;
    letter-spacing:-0.3px;
    color:var(--text-primary);
    margin-bottom:12px;
  }
  .status-bar{
    display:flex;
    align-items:center;
    gap:8px;
    padding:8px 12px;
    background:var(--bg-tertiary);
    border-radius:var(--radius-sm);
    font-size:12px;
  }
  .status-dot{
    width:8px;height:8px;border-radius:50%;
    background:var(--red);
    flex-shrink:0;
    transition:var(--transition);
  }
  .status-dot.connected{background:var(--green);}
  .status-text{color:var(--text-secondary);overflow:hidden;text-overflow:ellipsis;white-space:nowrap;}
  .conn-id{
    display:block;
    margin-top:8px;
    padding:6px 10px;
    background:var(--bg-primary);
    border-radius:var(--radius-sm);
    font-size:11px;
    color:var(--text-muted);
    font-family:monospace;
    word-break:break-all;
    line-height:1.4;
    min-height:30px;
  }
  .btn-connect{
    margin-top:10px;
    width:100%;
    padding:8px 0;
    border:none;
    border-radius:var(--radius-sm);
    background:var(--accent);
    color:#fff;
    font-size:13px;
    font-weight:500;
    cursor:pointer;
    transition:var(--transition);
  }
  .btn-connect:hover{background:var(--accent-hover);}
  .btn-connect:disabled{opacity:0.5;cursor:not-allowed;}
  .conn-btns{display:flex;gap:8px;margin-top:10px;}
  .conn-btns .btn-connect{margin-top:0;flex:1;}
  .btn-disconnect{
    flex:1;
    padding:8px 0;
    border:none;
    border-radius:var(--radius-sm);
    background:var(--red);
    color:#fff;
    font-size:13px;
    font-weight:500;
    cursor:pointer;
    transition:var(--transition);
  }
  .btn-disconnect:hover{opacity:0.85;}
  .btn-disconnect:disabled{opacity:0.4;cursor:not-allowed;}

  .sidebar-sections{
    flex:1;
    overflow-y:auto;
    padding:12px;
  }
  .sidebar-sections::-webkit-scrollbar{width:4px;}
  .sidebar-sections::-webkit-scrollbar-thumb{background:var(--border);border-radius:2px;}

  .section-label{
    font-size:11px;
    font-weight:600;
    text-transform:uppercase;
    letter-spacing:0.5px;
    color:var(--text-muted);
    padding:8px 8px 6px;
  }
  .session{
    display:flex;
    align-items:center;
    gap:10px;
    padding:10px 12px;
    border-radius:var(--radius);
    cursor:pointer;
    transition:var(--transition);
    margin-bottom:2px;
    position:relative;
  }
  .session:hover{background:var(--bg-hover);}
  .session.active{background:var(--bg-active);}
  .session-icon{
    width:36px;height:36px;
    border-radius:50%;
    display:flex;align-items:center;justify-content:center;
    font-size:14px;
    font-weight:600;
    flex-shrink:0;
  }
  .session-icon.public{background:var(--accent-soft);color:var(--accent);}
  .session-icon.group{background:var(--green-soft);color:var(--green);}
  .session-icon.private{background:var(--orange-soft);color:var(--orange);}
  .session-name{
    font-size:13px;
    font-weight:500;
    color:var(--text-primary);
    overflow:hidden;text-overflow:ellipsis;white-space:nowrap;
  }
  .session-badge{
    position:absolute;
    right:10px;
    top:50%;transform:translateY(-50%);
    min-width:18px;height:18px;
    border-radius:9px;
    background:var(--accent);
    color:#fff;
    font-size:11px;
    font-weight:600;
    display:flex;align-items:center;justify-content:center;
    padding:0 5px;
    display:none;
  }
  .session-badge.show{display:flex;}

  /* ===== Main ===== */
  .main{
    flex:1;
    display:flex;
    flex-direction:column;
    background:var(--bg-primary);
    overflow:hidden;
  }

  /* ===== Chat Header ===== */
  .chat-header{
    padding:16px 24px;
    border-bottom:1px solid var(--border);
    display:flex;
    align-items:center;
    gap:12px;
    background:var(--bg-secondary);
  }
  .chat-header-icon{
    width:32px;height:32px;
    border-radius:50%;
    display:flex;align-items:center;justify-content:center;
    font-size:13px;font-weight:600;
  }
  .chat-header-title{font-size:15px;font-weight:600;word-break:break-all;line-height:1.4;min-width:0;}
  .chat-header-sub{font-size:12px;color:var(--text-muted);margin-left:auto;flex-shrink:0;}

  /* ===== Chat Messages ===== */
  .chat-container{
    flex:1;
    overflow-y:auto;
    padding:20px 24px;
    display:flex;
    flex-direction:column;
    gap:4px;
  }
  .chat-container::-webkit-scrollbar{width:6px;}
  .chat-container::-webkit-scrollbar-thumb{background:var(--border);border-radius:3px;}

  .message-row{display:flex;max-width:70%;animation:fadeIn 0.2s ease;}
  .message-row.self{align-self:flex-end;flex-direction:column;align-items:flex-end;}
  .message-row.other{align-self:flex-start;flex-direction:row;align-items:flex-start;gap:8px;}
  .msg-avatar{
    width:32px;height:32px;
    border-radius:50%;
    background:var(--bg-active);
    color:var(--text-secondary);
    display:flex;align-items:center;justify-content:center;
    font-size:13px;font-weight:600;font-family:monospace;
    flex-shrink:0;
    cursor:pointer;
    transition:var(--transition);
    border:2px solid transparent;
    margin-top:2px;
  }
  .msg-avatar:hover{
    border-color:var(--orange);
    background:var(--orange-soft);
    color:var(--orange);
  }
  .msg-avatar[title]:hover::after{
    content:"";
  }
  .msg-bubble-col{display:flex;flex-direction:column;align-items:flex-start;min-width:0;}

  @keyframes fadeIn{from{opacity:0;transform:translateY(6px);}to{opacity:1;transform:translateY(0);}}

  .bubble{
    padding:10px 14px;
    border-radius:var(--radius-lg);
    font-size:14px;
    line-height:1.5;
    word-break:break-word;
    position:relative;
  }
  .message-row.self .bubble{
    background:var(--bubble-self);
    color:#fff;
    border-bottom-right-radius:4px;
  }
  .message-row.other .bubble{
    background:var(--bubble-other);
    color:var(--text-primary);
    border-bottom-left-radius:4px;
  }
  .bubble .meta{
    margin-top:6px;
    font-size:11px;
    opacity:0.6;
    line-height:1.3;
    word-break:break-all;
    cursor:text;
    user-select:text;
  }
  .message-row.self .bubble .meta{text-align:right;}
  .meta-sender{
    user-select:all;
    cursor:text;
    font-family:monospace;
    font-size:10px;
    display:inline;
  }

  .system-msg{
    align-self:center;
    padding:6px 16px;
    background:var(--bg-tertiary);
    border-radius:20px;
    font-size:12px;
    color:var(--text-muted);
    margin:8px 0;
  }

  .empty-state{
    flex:1;
    display:flex;
    flex-direction:column;
    align-items:center;
    justify-content:center;
    color:var(--text-muted);
    gap:12px;
  }
  .empty-state svg{width:48px;height:48px;opacity:0.3;}
  .empty-state p{font-size:14px;}

  /* ===== Input Area ===== */
  .input-area{
    padding:16px 24px;
    border-top:1px solid var(--border);
    background:var(--bg-secondary);
  }
  .input-controls{
    display:flex;
    gap:8px;
    margin-bottom:10px;
    flex-wrap:wrap;
  }
  .input-controls input[type="text"]{
    flex:1;
    min-width:120px;
    padding:8px 12px;
    background:var(--bg-tertiary);
    border:1px solid var(--border);
    border-radius:var(--radius-sm);
    color:var(--text-primary);
    font-size:13px;
    outline:none;
    transition:var(--transition);
  }
  .input-controls input[type="text"]:focus{border-color:var(--accent);}
  .input-controls input[type="text"]::placeholder{color:var(--text-muted);}

  .btn{
    padding:8px 14px;
    border:none;
    border-radius:var(--radius-sm);
    font-size:12px;
    font-weight:500;
    cursor:pointer;
    transition:var(--transition);
    white-space:nowrap;
  }
  .btn-primary{background:var(--accent);color:#fff;}
  .btn-primary:hover{background:var(--accent-hover);}
  .btn-success{background:var(--green);color:#fff;}
  .btn-success:hover{opacity:0.85;}
  .btn-warning{background:var(--orange);color:#000;}
  .btn-warning:hover{opacity:0.85;}
  .btn-danger{background:var(--red);color:#fff;}
  .btn-danger:hover{opacity:0.85;}
  .btn:disabled{opacity:0.4;cursor:not-allowed;}

  .msg-input-row{display:flex;gap:8px;}
  .msg-input-row input[type="text"]{
    flex:1;
    padding:10px 16px;
    background:var(--bg-tertiary);
    border:1px solid var(--border);
    border-radius:var(--radius-lg);
    color:var(--text-primary);
    font-size:14px;
    outline:none;
    transition:var(--transition);
  }
  .msg-input-row input[type="text"]:focus{border-color:var(--accent);}
  .msg-input-row input[type="text"]::placeholder{color:var(--text-muted);}
  .btn-send{
    width:40px;height:40px;
    border:none;
    border-radius:50%;
    background:var(--accent);
    color:#fff;
    cursor:pointer;
    display:flex;align-items:center;justify-content:center;
    transition:var(--transition);
    flex-shrink:0;
  }
  .btn-send:hover{background:var(--accent-hover);}
  .btn-send:disabled{opacity:0.4;cursor:not-allowed;}
  .btn-send svg{width:18px;height:18px;}

  /* ===== Toast ===== */
  .toast-container{
    position:fixed;top:20px;right:20px;
    display:flex;flex-direction:column;gap:8px;z-index:1000;
  }
  .toast{
    padding:10px 16px;
    border-radius:var(--radius);
    font-size:13px;
    color:#fff;
    box-shadow:var(--shadow);
    animation:slideIn 0.3s ease,fadeOut 0.3s ease 2.7s forwards;
  }
  .toast.info{background:var(--accent);}
  .toast.success{background:var(--green);}
  .toast.error{background:var(--red);}

  @keyframes slideIn{from{transform:translateX(100%);opacity:0;}to{transform:translateX(0);opacity:1;}}
  @keyframes fadeOut{to{opacity:0;transform:translateY(-10px);}}

  /* ===== Responsive ===== */
  @media(max-width:768px){
    .sidebar{width:220px;min-width:220px;}
    .message-row{max-width:85%;}
  }
  @media(max-width:560px){
    .app{flex-direction:column;}
    .sidebar{
      width:100%;min-width:100%;
      max-height:180px;
      border-right:none;
      border-bottom:1px solid var(--border);
    }
    .sidebar-header{padding:12px;}
    .sidebar-sections{padding:8px;display:flex;gap:6px;overflow-x:auto;overflow-y:hidden;}
    .session{flex-shrink:0;}
    .section-label{display:none;}
  }
</style>
</head>
<body>

<div class="app">
  <!-- Sidebar -->
  <aside class="sidebar">
    <div class="sidebar-header">
      <h2>SignalR Chat</h2>
      <div class="status-bar">
        <span class="status-dot" id="statusDot"></span>
        <span class="status-text" id="status">未连接</span>
      </div>
      <div class="conn-id" id="connectionId">--</div>
      <div class="conn-btns">
        <button class="btn-connect" id="btnConnect" onclick="initConnection()">连接 SignalR 服务器</button>
        <button class="btn-disconnect" id="btnDisconnect" onclick="disconnect()" disabled>断开连接</button>
      </div>
    </div>
    <div class="sidebar-sections" id="sessionList">
      <div class="section-label">会话列表</div>
    </div>
  </aside>

  <!-- Main Area -->
  <div class="main">
    <div class="chat-header" id="chatHeader">
      <div class="chat-header-icon public" id="chatHeaderIcon">P</div>
      <span class="chat-header-title" id="chatHeaderTitle">公共频道</span>
      <span class="chat-header-sub" id="chatHeaderSub">广播消息</span>
    </div>

    <div class="chat-container" id="chatContainer">
      <div class="empty-state" id="emptyState">
        <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5">
          <path d="M21 15a2 2 0 01-2 2H7l-4 4V5a2 2 0 012-2h14a2 2 0 012 2z"/>
        </svg>
        <p>请先连接服务器，然后开始聊天</p>
      </div>
    </div>

    <div class="input-area">
      <div class="input-controls">
        <input type="text" id="targetUser" placeholder="私聊目标 ConnectionId" />
        <button class="btn btn-warning" onclick="openPrivateChat()" disabled id="btnSendUser">开始私聊</button>
        <input type="text" id="groupName" placeholder="组名" />
        <button class="btn btn-success" onclick="joinGroup()" disabled id="btnJoinGroup">加入组</button>
        <button class="btn btn-danger" onclick="leaveGroup()" disabled id="btnLeaveGroup">退出组</button>
        <button class="btn btn-primary" onclick="sendGroup()" disabled id="btnSendGroup">发送到组</button>
      </div>
      <div class="msg-input-row">
        <input type="text" id="message" placeholder="输入消息内容，Enter 发送..." onkeydown="handleKeyDown(event)" />
        <button class="btn-send" onclick="smartSend()" disabled id="btnSend">
          <svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
            <line x1="22" y1="2" x2="11" y2="13"/><polygon points="22 2 15 22 11 13 2 9 22 2"/>
          </svg>
        </button>
      </div>
    </div>
  </div>
</div>

<div class="toast-container" id="toastContainer"></div>

<script>
  /* ================= State ================= */
  let connection = null;
  let chatSections = {};
  let currentSection = "public";
  let connectionId = null;

  /* ================= Toast ================= */
  function showToast(msg, type) {
    type = type || "info";
    var container = document.getElementById("toastContainer");
    var toast = document.createElement("div");
    toast.className = "toast " + type;
    toast.textContent = msg;
    container.appendChild(toast);
    setTimeout(function() { toast.remove(); }, 3000);
  }

  /* ================= 初始化连接 ================= */
  function initConnection() {
    var btn = document.getElementById("btnConnect");
    btn.disabled = true;
    btn.textContent = "连接中...";
    document.getElementById("status").textContent = "连接中...";

    connection = new signalR.HubConnectionBuilder()
      .withUrl("http://localhost:5097/chatHub")
      .withAutomaticReconnect()
      .build();

    /* 接收服务器确认 connectionId */
    connection.on("ConnectionAck", function(id) {
      connectionId = id;
      document.getElementById("connectionId").textContent = id;
      document.getElementById("status").textContent = "已连接";
      document.getElementById("statusDot").classList.add("connected");
      btn.textContent = "已连接";
      btn.disabled = true;
      document.getElementById("btnDisconnect").disabled = false;
      enableButtons(true);
      createSection("public");
      showToast("连接成功! ID: " + id, "success");

      /* 重���后重新加入所有已有的组 */
      Object.keys(chatSections).forEach(function(key) {
        if (key !== "public" && !key.startsWith("pm_")) {
          connection.invoke("JoinGroup", key).catch(function() {});
        }
      });
    });

    /* 接收消息（广播 / 组 / 私聊） */
    connection.on("ReceiveMessage", function(msg) {
      appendMessage(msg, true);
    });

    /* 断线事件 */
    connection.onclose(function() {
      document.getElementById("status").textContent = "已断开";
      document.getElementById("statusDot").classList.remove("connected");
      enableButtons(false);
      document.getElementById("btnDisconnect").disabled = true;
      btn.disabled = false;
      btn.textContent = "重新连接";
      showToast("连接已断开", "error");
    });

    /* 重连中 */
    connection.onreconnecting(function() {
      document.getElementById("status").textContent = "重连中...";
      document.getElementById("statusDot").classList.remove("connected");
      showToast("正在重新连接...", "info");
    });

    /* 重连成功 */
    connection.onreconnected(function(newId) {
      document.getElementById("status").textContent = "已重连";
      document.getElementById("statusDot").classList.add("connected");
      showToast("重连成功!", "success");
    });

    connection.start()
      .then(function() {
        console.log("SignalR ���连接");
      })
      .catch(function(err) {
        console.error("SignalR 连接失败:", err);
        document.getElementById("status").textContent = "连接失败";
        btn.disabled = false;
        btn.textContent = "重新连接";
        showToast("连接失败: " + err.message, "error");
      });
  }

  /* ================= 手动断开连接 ================= */
  async function disconnect() {
    if (!connection) {
      showToast("当前未创建连接", "error");
      return;
    }
    if (connection.state === signalR.HubConnectionState.Disconnected) {
      showToast("已经是断开状态", "error");
      return;
    }
    var disconnectBtn = document.getElementById("btnDisconnect");
    disconnectBtn.disabled = true;
    disconnectBtn.textContent = "断开中...";
    try {
      await connection.stop();
      connectionId = null;
      document.getElementById("connectionId").textContent = "--";
      showToast("已手动断开连接", "success");
    } catch (err) {
      showToast("断开失败: " + err.message, "error");
    }
    disconnectBtn.textContent = "断开连接";
  }

  /* ================= 按钮启用/禁用 ================= */
  function enableButtons(enable) {
    document.getElementById("btnSendUser").disabled = !enable;
    document.getElementById("btnJoinGroup").disabled = !enable;
    document.getElementById("btnLeaveGroup").disabled = !enable;
    document.getElementById("btnSendGroup").disabled = !enable;
    document.getElementById("btnSend").disabled = !enable;
  }

  /* ================= 创建消息对象 ================= */
  function createMessage(group, target, receiver) {
    return {
      Sender: connectionId,
      Receiver: receiver || null,
      Content: document.getElementById("message").value,
      SendTime: new Date().toISOString(),
      Group: group || null,
      Target: target || null
    };
  }

  /* ================= 智能发送 ================= */
  function smartSend() {
    if (!connectionId) return;
    var msgVal = document.getElementById("message").value.trim();
    if (!msgVal) return;

    if (currentSection === "public") {
      sendAll();
    } else if (currentSection.startsWith("pm_")) {
      var target = currentSection.substring(3);
      sendUser(target);
    } else {
      document.getElementById("groupName").value = currentSection;
      sendGroup();
    }
  }

  /* ================= 广播消息 ================= */
  function sendAll() {
    if (!connectionId) return;
    var msgVal = document.getElementById("message").value.trim();
    if (!msgVal) return;
    var msg = createMessage();
    connection.invoke("BroadcastMessage", msg)
      .catch(function(err) { showToast("发送失败: " + err.message, "error"); });
    document.getElementById("message").value = "";
  }

  /* ================= 开始私聊（创建分区并切换） ================= */
  function openPrivateChat() {
    if (!connectionId) { showToast("请先连接 SignalR 服务器", "error"); return; }
    var target = document.getElementById("targetUser").value.trim();
    if (!target) { showToast("请输入私聊目标 ConnectionId", "error"); return; }
    if (target === connectionId) { showToast("不能和自己私聊", "error"); return; }

    var sectionKey = "pm_" + target;
    if (!chatSections[sectionKey]) createSection(sectionKey);
    switchSection(sectionKey);
    showToast("已打开与 " + target + " 的私聊", "success");
  }

  /* ================= 私聊消息（在分区内发送） ================= */
  function sendUser(targetOverride) {
    if (!connectionId) return;
    var target = targetOverride || document.getElementById("targetUser").value.trim();
    if (!target) { showToast("请输入私聊目标 ID", "error"); return; }
    var msgVal = document.getElementById("message").value.trim();
    if (!msgVal) return;

    var msg = createMessage(null, target, target);
    var sectionKey = "pm_" + target;

    /* 发送方本地存储并渲染 */
    if (!chatSections[sectionKey]) createSection(sectionKey);
    chatSections[sectionKey].push(msg);

    if (currentSection === sectionKey) {
      renderSingleMessage(msg, false);
    }

    connection.invoke("SendMessageToUser", target, msg)
      .catch(function(err) { showToast("私聊发送失败: " + err.message, "error"); });
    document.getElementById("message").value = "";
  }

  /* ================= 加入组 ================= */
  function joinGroup() {
    if (!connectionId) return;
    var group = document.getElementById("groupName").value.trim();
    if (!group) { showToast("请输入组名", "error"); return; }

    connection.invoke("JoinGroup", group)
      .then(function() {
        createSection(group);
        switchSection(group);
        showToast("已加入组: " + group, "success");
      })
      .catch(function(err) { showToast("加入组失败: " + err.message, "error"); });
  }

  /* ================= 退出组 ================= */
  function leaveGroup() {
    if (!connection || !connectionId) { showToast("请先连接 SignalR 服务器", "error"); return; }
    var group = document.getElementById("groupName").value.trim();
    if (!group) { showToast("请输入组名", "error"); return; }

    if (!chatSections[group]) {
      showToast("你不在组 " + group + " 中", "error");
      return;
    }

    connection.invoke("LeaveGroup", group)
      .then(function() {
        showToast("已退出组: " + group, "success");

        /* 删除该分区数据 */
        delete chatSections[group];

        /* 从侧边栏中移除该会话 */
        var sessionEl = document.querySelector('.session[data-section="' + group + '"]');
        if (sessionEl) sessionEl.remove();

        /* 如果当前正在查看该组，切换到其他分区 */
        if (currentSection === group) {
          var keys = Object.keys(chatSections);
          if (keys.length > 0) {
            switchSection(keys[0]);
          } else {
            currentSection = "public";
            createSection("public");
            switchSection("public");
          }
        }
      })
      .catch(function(err) { showToast("退出组失败: " + err.message, "error"); });
  }

  /* ================= 组消息 ================= */
  function sendGroup() {
    if (!connectionId) return;
    var group = document.getElementById("groupName").value.trim();
    if (!group) { showToast("请输入组名", "error"); return; }
    var msgVal = document.getElementById("message").value.trim();
    if (!msgVal) return;

    var msg = createMessage(group);
    connection.invoke("SendMessageToGroup", group, msg)
      .catch(function(err) { showToast("组消息发送失败: " + err.message, "error"); });
    document.getElementById("message").value = "";
  }

  /* ================= 回车发送 ================= */
  function handleKeyDown(e) {
    if (e.key === "Enter" && !e.shiftKey) {
      e.preventDefault();
      smartSend();
    }
  }

  /* ================= 消息渲染 ================= */
  function appendMessage(msg, store) {
    var sender = msg.sender || msg.Sender;
    var content = msg.content || msg.Content;
    var time = new Date(msg.sendTime || msg.SendTime || new Date());
    var group = msg.group || msg.Group || null;
    var target = msg.target || msg.Target || null;
    var receiver = msg.receiver || msg.Receiver || null;

    var section;
    if (group) {
      /* 组消息 */
      section = group;
    } else if (receiver) {
      /*
       * 有 Receiver 字段 → 一定是私聊消息
       * - Receiver 等于自己 → 别人发给自己的，归入 pm_sender
       * - Receiver 不等于自己 → 自己发的（不应走到这里，发送方本地已处理），
       *   但作为 fallback 归入 pm_receiver
       */
      if (receiver === connectionId) {
        section = "pm_" + sender;
      } else {
        section = "pm_" + receiver;
      }
    } else if (target) {
      /*
       * 兼容旧逻辑：有 Target 但无 Receiver
       */
      if (sender === connectionId) {
        section = "pm_" + target;
      } else {
        section = "pm_" + sender;
      }
    } else {
      /* 无 Group、无 Receiver、无 Target → 广播消息 */
      section = "public";
    }

    if (store) {
      if (!chatSections[section]) createSection(section);
      chatSections[section].push(msg);

      /* 如果不是当前分区，显示未读标记 */
      if (section !== currentSection) {
        showBadge(section);
      }
    }

    /* 只渲染当前分区 */
    if (section !== currentSection) return;

    renderSingleMessage(msg, store);
  }

  function renderSingleMessage(msg, animate) {
    var sender = msg.sender || msg.Sender;
    var content = msg.content || msg.Content;
    var time = new Date(msg.sendTime || msg.SendTime || new Date());
    var isSelf = sender === connectionId;

    var emptyState = document.getElementById("emptyState");
    if (emptyState) emptyState.remove();

    var container = document.getElementById("chatContainer");
    var row = document.createElement("div");
    row.className = "message-row " + (isSelf ? "self" : "other");

    /* 非自己的消息：添加可点击头像（仅在公共和组频道中可跳转私聊） */
    if (!isSelf && sender) {
      var avatar = document.createElement("div");
      avatar.className = "msg-avatar";
      avatar.textContent = sender.charAt(0).toUpperCase();
      avatar.title = "点击私聊 " + sender;
      avatar.onclick = (function(sid) {
        return function(e) {
          e.stopPropagation();
          openPmFromAvatar(sid);
        };
      })(sender);
      row.appendChild(avatar);
    }

    var bubbleCol = document.createElement("div");
    bubbleCol.className = "msg-bubble-col";
    if (isSelf) {
      bubbleCol.style.alignItems = "flex-end";
    }

    var bubble = document.createElement("div");
    bubble.className = "bubble";

    var contentDiv = document.createElement("div");
    contentDiv.textContent = content;

    var metaDiv = document.createElement("div");
    metaDiv.className = "meta";
    var senderDisplay = sender || "unknown";
    var timeStr = time.toLocaleTimeString("zh-CN", { hour: "2-digit", minute: "2-digit", second: "2-digit" });
    metaDiv.innerHTML = '<span class="meta-sender" title="' + senderDisplay + '">' + senderDisplay + '</span> &middot; ' + timeStr;

    bubble.appendChild(contentDiv);
    bubble.appendChild(metaDiv);
    bubbleCol.appendChild(bubble);
    row.appendChild(bubbleCol);
    container.appendChild(row);

    /* 自动滚动到底部 */
    container.scrollTop = container.scrollHeight;
  }

  /* ================= 通过头像跳转私聊 ================= */
  function openPmFromAvatar(senderId) {
    if (!connectionId) { showToast("请先连接 SignalR 服务器", "error"); return; }
    if (senderId === connectionId) return;

    var sectionKey = "pm_" + senderId;
    if (!chatSections[sectionKey]) createSection(sectionKey);
    switchSection(sectionKey);
    showToast("已打开与 " + senderId + " 的私聊", "success");
  }

  /* ================= 创建分区 / 会话 ================= */
  function createSection(name) {
    if (chatSections[name]) return;
    chatSections[name] = [];

    var list = document.getElementById("sessionList");
    var div = document.createElement("div");
    div.className = "session";
    div.setAttribute("data-section", name);

    var icon = document.createElement("div");
    icon.className = "session-icon";

    var nameSpan = document.createElement("span");
    nameSpan.className = "session-name";

    var badge = document.createElement("span");
    badge.className = "session-badge";
    badge.id = "badge_" + name;

    if (name === "public") {
      icon.classList.add("public");
      icon.textContent = "P";
      nameSpan.textContent = "公共频道";
    } else if (name.startsWith("pm_")) {
      icon.classList.add("private");
      var uid = name.substring(3);
      icon.textContent = uid.charAt(0).toUpperCase();
      nameSpan.textContent = uid;
      nameSpan.title = uid;
      nameSpan.style.fontSize = "11px";
      nameSpan.style.wordBreak = "break-all";
      nameSpan.style.whiteSpace = "normal";
      nameSpan.style.lineHeight = "1.3";
    } else {
      icon.classList.add("group");
      icon.textContent = "G";
      nameSpan.textContent = name;
    }

    div.appendChild(icon);
    div.appendChild(nameSpan);
    div.appendChild(badge);

    div.onclick = function() { switchSection(name); };
    list.appendChild(div);

    if (Object.keys(chatSections).length === 1) {
      switchSection(name);
    }
  }

  function switchSection(name) {
    currentSection = name;

    /* 更新侧边栏高亮 */
    var sessions = document.querySelectorAll(".session");
    sessions.forEach(function(s) {
      s.classList.remove("active");
      if (s.getAttribute("data-section") === name) {
        s.classList.add("active");
      }
    });

    /* 隐藏未读标记 */
    hideBadge(name);

    /* 更新头部 */
    updateChatHeader(name);

    /* 渲染消息 */
    renderMessages();
  }

  function updateChatHeader(name) {
    var iconEl = document.getElementById("chatHeaderIcon");
    var titleEl = document.getElementById("chatHeaderTitle");
    var subEl = document.getElementById("chatHeaderSub");

    iconEl.className = "chat-header-icon";

    if (name === "public") {
      iconEl.classList.add("public");
      iconEl.textContent = "P";
      titleEl.textContent = "公共频道";
      subEl.textContent = "广播消息";
    } else if (name.startsWith("pm_")) {
      var pmUid = name.substring(3);
      iconEl.classList.add("private");
      iconEl.textContent = pmUid.charAt(0).toUpperCase();
      titleEl.textContent = "私聊: " + pmUid;
      subEl.textContent = "私密消息";
    } else {
      iconEl.classList.add("group");
      iconEl.textContent = "G";
      titleEl.textContent = "组: " + name;
      subEl.textContent = "组消息";
    }
  }

  function renderMessages() {
    var container = document.getElementById("chatContainer");
    container.innerHTML = "";
    var msgs = chatSections[currentSection] || [];
    if (msgs.length === 0) {
      var empty = document.createElement("div");
      empty.className = "empty-state";
      empty.id = "emptyState";
      empty.innerHTML = '<svg viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5"><path d="M21 15a2 2 0 01-2 2H7l-4 4V5a2 2 0 012-2h14a2 2 0 012 2z"/></svg><p>暂无消息，开始聊天吧</p>';
      container.appendChild(empty);
      return;
    }
    msgs.forEach(function(msg) {
      renderSingleMessage(msg, false);
    });
  }

  /* ================= 未读标记 ================= */
  function showBadge(section) {
    var badge = document.getElementById("badge_" + section);
    if (badge) {
      var count = parseInt(badge.textContent || "0") + 1;
      badge.textContent = count;
      badge.classList.add("show");
    }
  }

  function hideBadge(section) {
    var badge = document.getElementById("badge_" + section);
    if (badge) {
      badge.textContent = "";
      badge.classList.remove("show");
    }
  }
</script>

</body>
</html>