前端：

1、完善创建群聊逻辑
后端：
1、完善群聊相关接口

backend/IM_API/Hubs/ChatHub.cs

@@ -7,6 +7,7 @@ using IM_API.Models;
 using IM_API.Tools;
 using IM_API.VOs.Message;
 using Microsoft.AspNetCore.SignalR;
+using StackExchange.Redis;
 using System.Security.Claims;
 
 namespace IM_API.Hubs
@@ -15,14 +16,13 @@ namespace IM_API.Hubs
     {
         private IMessageSevice _messageService;
         private readonly IConversationService _conversationService;
-        private readonly IEventBus _eventBus;
-        private readonly IMapper _mapper;
-        public ChatHub(IMessageSevice messageService, IConversationService conversationService, IEventBus eventBus, IMapper mapper)
+        private readonly IDatabase _redis;
+        public ChatHub(IMessageSevice messageService, IConversationService conversationService, 
+            IConnectionMultiplexer connectionMultiplexer)
         {
             _messageService = messageService;
             _conversationService = conversationService;
-            _eventBus = eventBus;
-            _mapper = mapper;
+            _redis = connectionMultiplexer.GetDatabase();
         }
 
         public async override Task OnConnectedAsync()
@@ -32,6 +32,7 @@ namespace IM_API.Hubs
                 Context.Abort();
                 return;
             }
+
             //将用户加入已加入聊天的会话组
             string userIdStr = Context.User.FindFirstValue(ClaimTypes.NameIdentifier);
             var keys = await _conversationService.GetUserAllStreamKeyAsync(int.Parse(userIdStr));
@@ -39,8 +40,20 @@ namespace IM_API.Hubs
             {
                 await Groups.AddToGroupAsync(Context.ConnectionId, key);
             }
+            //储存用户对应的连接id
+            await _redis.SetAddAsync(RedisKeys.GetConnectionIdKey(userIdStr), Context.ConnectionId);
             await base.OnConnectedAsync();
         }
+
+        public override async Task OnDisconnectedAsync(Exception? exception)
+        {
+            if (!Context.User.Identity.IsAuthenticated)
+            {
+                string useridStr = Context.User.FindFirstValue(ClaimTypes.NameIdentifier);
+                await _redis.SetRemoveAsync(RedisKeys.GetConnectionIdKey(useridStr), Context.ConnectionId);
+            }
+            await base.OnDisconnectedAsync(exception);
+        }
         public async Task<HubResponse<MessageBaseVo?>> SendMessage(MessageBaseDto dto)
         {
             if (!Context.User.Identity.IsAuthenticated)