后端：

1、事件订阅增加rabbitmq中间件
移动端：
1、完善移动端目录结构和代码框架

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

@@ -0,0 +1,63 @@
+using AutoMapper;
+using IM_API.Application.Interfaces;
+using IM_API.Domain.Events;
+using IM_API.Dtos;
+using IM_API.Exceptions;
+using IM_API.Interface.Services;
+using IM_API.Models;
+using IM_API.Services;
+using IM_API.Tools;
+using MassTransit;
+using Microsoft.EntityFrameworkCore;
+using Newtonsoft.Json;
+
+namespace IM_API.Application.EventHandlers.MessageCreatedHandler
+{
+    public class ConversationEventHandler : IConsumer<MessageCreatedEvent>
+    {
+        private readonly IConversationService _conversationService;
+        private readonly ILogger<ConversationEventHandler> _logger;
+        private readonly ImContext _context;
+        private readonly IMapper _mapper;
+        public ConversationEventHandler(
+            IConversationService conversationService,
+            ILogger<ConversationEventHandler> logger,
+            ImContext imContext,
+            IMapper mapper
+            )
+        {
+            _conversationService = conversationService;
+            _logger = logger;
+            _context = imContext;
+            _mapper = mapper;
+        }
+
+        public async Task Consume(ConsumeContext<MessageCreatedEvent> context)
+        {
+            var @event = context.Message;
+
+            if (@event.ChatType == ChatType.PRIVATE)
+            {
+                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();
+            }
+        }
+
+    }
+}

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

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+using AutoMapper;
+using IM_API.Application.Interfaces;
+using IM_API.Domain.Events;
+using IM_API.Dtos;
+using IM_API.Hubs;
+using IM_API.Models;
+using IM_API.Tools;
+using MassTransit;
+using Microsoft.AspNetCore.SignalR;
+
+namespace IM_API.Application.EventHandlers.MessageCreatedHandler
+{
+    public class SignalREventHandler : IConsumer<MessageCreatedEvent>
+    {
+        private readonly IHubContext<ChatHub> _hub;
+        private readonly IMapper _mapper;
+        public SignalREventHandler(IHubContext<ChatHub> hub, IMapper mapper)
+        {
+            _hub = hub;
+            _mapper = mapper;
+        }
+
+        public async Task Consume(ConsumeContext<MessageCreatedEvent> context)
+        {
+            var @event = context.Message;
+            if (@event.ChatType == Models.ChatType.PRIVATE)
+            {
+                MessageBaseDto messageBaseDto = new MessageBaseDto
+                {
+                    MsgId = @event.MessageId.ToString(),
+                    ChatType = @event.ChatType.ToString(),
+                    Content = @event.MessageContent,
+                    GroupMemberId = null,
+                    ReceiverId = @event.MsgRecipientId,
+                    SenderId = @event.MsgSenderId,
+                    TimeStamp = @event.MessageCreated,
+                    Type = @event.MessageMsgType.ToString()
+                };
+                await _hub.Clients.Users(@event.MsgRecipientId.ToString()).SendAsync("ReceiveMessage", messageBaseDto);
+            }
+        }
+    }
+}