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

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 IM_API.VOs.Message;
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)
        {
            Console.ForegroundColor = ConsoleColor.Red;
            var @event = context.Message;
            Console.WriteLine($"[SignalR]handlerCreated!");
            try
            {
                // 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
            }
        }
    }
}