前端：

1、优化消息排序逻辑
2、新增加载历史消息
3、修复已知问题
后端：
1、优化消息排序逻辑
2、增加用户信息缓存机制
3、修改日期类型为DateTimeOffset改善时区信息丢失问题
3、修复了已知问题
数据库：
1、新增SequenceId字段用于消息排序
2、新增ClientMsgId字段用于客户端消息回执

backend/IM_API/Application/EventHandlers/FriendAddHandler/FriendAddSignalRHandler.cs

@@ -26,10 +26,10 @@ namespace IM_API.Application.EventHandlers.FriendAddHandler
             {
                 ChatType = ChatType.PRIVATE,
                 Content = "您有新的好友关系已添加",
-                MsgId = @event.EventId.ToString(),
+                //MsgId = @event.EventId.ToString(),
                 ReceiverId = @event.ResponseUserId,
                 SenderId = @event.RequestUserId,
-                TimeStamp = DateTime.UtcNow
+                TimeStamp = DateTime.Now
             });
             await _chathub.Clients.Users(usersList).SendAsync("ReceiveMessage", res);
         }

backend/IM_API/Application/EventHandlers/MessageCreatedHandler/ConversationEventHandler.cs

@@ -35,28 +35,15 @@ namespace IM_API.Application.EventHandlers.MessageCreatedHandler
         public async Task Consume(ConsumeContext<MessageCreatedEvent> context)
         {
             var @event = context.Message;
-
-            if (@event.ChatType == ChatType.PRIVATE)
+            await _conversationService.UpdateConversationAfterSentAsync(new Dtos.Conversation.UpdateConversationDto
             {
-                Conversation? userAConversation = await _context.Conversations.FirstOrDefaultAsync(
-                    x => x.UserId == @event.MsgSenderId && x.TargetId == @event.MsgRecipientId
-                    );
-                Conversation? userBConversation = await _context.Conversations.FirstOrDefaultAsync(
-                    x => x.UserId == @event.MsgRecipientId && x.TargetId == @event.MsgSenderId
-                    );
-                if (userAConversation is null || userBConversation is null)
-                {
-                    _logger.LogError("消息事件更新会话信息失败：{@event}", @event);
-                }
-                userAConversation.LastMessage = @event.MessageContent;
-                userAConversation.LastReadMessageId = @event.MessageId;
-                userAConversation.LastMessageTime = @event.MessageCreated;
-                userBConversation.LastMessage = @event.MessageContent;
-                userBConversation.UnreadCount += 1;
-                userBConversation.LastMessageTime = @event.MessageCreated;
-                _context.UpdateRange(userAConversation, userBConversation);
-                await _context.SaveChangesAsync();
-            }
+                LastMessage = @event.MessageContent,
+                LastSequenceId = @event.SequenceId,
+                ReceiptId = @event.MsgRecipientId,
+                SenderId = @event.MsgSenderId,
+                StreamKey = @event.StreamKey,
+                DateTime = @event.MessageCreated
+            });
         }
 
     }

backend/IM_API/Application/EventHandlers/MessageCreatedHandler/MessageCreatedDbHandler.cs

@@ -0,0 +1,26 @@
+using IM_API.Domain.Events;
+using MassTransit;
+using IM_API.Interface.Services;
+using AutoMapper;
+using IM_API.Models;
+
+namespace IM_API.Application.EventHandlers.MessageCreatedHandler
+{
+    public class MessageCreatedDbHandler : IConsumer<MessageCreatedEvent>
+    {
+        private readonly IMessageSevice _messageService;
+        public readonly IMapper _mapper;
+        public MessageCreatedDbHandler(IMessageSevice messageSevice, IMapper mapper)
+        {
+            _messageService = messageSevice;
+            _mapper = mapper;
+        }
+
+        public async Task Consume(ConsumeContext<MessageCreatedEvent> context)
+        {
+            var @event = context.Message;
+            var msg = _mapper.Map<Message>(@event);
+            await _messageService.MakeMessageAsync(msg);
+        }
+    }
+}

backend/IM_API/Application/EventHandlers/MessageCreatedHandler/SignalREventHandler.cs

@@ -5,6 +5,7 @@ using IM_API.Dtos;
 using IM_API.Hubs;
 using IM_API.Models;
 using IM_API.Tools;
+using IM_API.VOs.Message;
 using MassTransit;
 using Microsoft.AspNetCore.SignalR;
 
@@ -22,21 +23,31 @@ namespace IM_API.Application.EventHandlers.MessageCreatedHandler
 
         public async Task Consume(ConsumeContext<MessageCreatedEvent> context)
         {
+            Console.ForegroundColor = ConsoleColor.Red;
             var @event = context.Message;
-            if (@event.ChatType == Models.ChatType.PRIVATE)
+            Console.WriteLine($"[SignalR]handlerCreated!");
+            try
             {
-                MessageBaseDto messageBaseDto = new MessageBaseDto
-                {
-                    MsgId = @event.MessageId.ToString(),
-                    ChatType = @event.ChatType,
-                    Content = @event.MessageContent,
-                    GroupMemberId = null,
-                    ReceiverId = @event.MsgRecipientId,
-                    SenderId = @event.MsgSenderId,
-                    TimeStamp = @event.MessageCreated,
-                    Type = @event.MessageMsgType
-                };
-                await _hub.Clients.Users(@event.MsgRecipientId.ToString()).SendAsync("ReceiveMessage", messageBaseDto);
+                // 先转成实体，如果这一步都报错，说明之前的 sbyte -> enum 还没改好
+                var entity = _mapper.Map<Message>(@event);
+
+                // 再从实体转 VO，这是最稳妥的路径，因为这两者的映射你肯定配过了
+                var messageBaseVo = _mapper.Map<MessageBaseVo>(entity);
+
+                // 2. 打印日志确认逻辑执行到这里了
+                Console.WriteLine($"[SignalR] 准备向所有人广播消息: {messageBaseVo.Content}");
+
+                // 3. 执行广播
+                await _hub.Clients.User(@event.MsgRecipientId.ToString()).SendAsync("ReceiveMessage", new HubResponse<MessageBaseVo>("Event", messageBaseVo));
+
+                Console.WriteLine("[SignalR] 广播指令已发出");
+                Console.ResetColor();
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine($"[SignalR] 发送失败: {ex.Message}");
+                Console.ResetColor();
+                throw; // 抛出异常触发 MassTransit 重试
             }
         }
     }