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/Services/UserService.cs

@@ -5,6 +5,7 @@ using IM_API.Interface.Services;
 using IM_API.Models;
 using IM_API.Tools;
 using Microsoft.EntityFrameworkCore;
+using StackExchange.Redis;
 
 namespace IM_API.Services
 {
@@ -13,31 +14,43 @@ namespace IM_API.Services
         private readonly ImContext _context;
         private readonly ILogger<UserService> _logger;
         private readonly IMapper _mapper;
-        public UserService(ImContext imContext,ILogger<UserService> logger,IMapper mapper)
+        private readonly ICacheService _cacheService;
+        public UserService(ImContext imContext,ILogger<UserService> logger,IMapper mapper, ICacheService cacheService)
         {
             this._context = imContext;
             this._logger = logger;
             this._mapper = mapper;
+            _cacheService = cacheService;
         }
         #region 获取用户信息
         public async Task<UserInfoDto> GetUserInfoAsync(int userId)
         {
-            var user = await _context.Users.FirstOrDefaultAsync(x => x.Id == userId);
+            //查询redis缓存，如果存在直接返回不走查库逻辑
+            var key = RedisKeys.GetUserinfoKey(userId.ToString());
+            var userinfoCache = await _cacheService.GetAsync<User>(key);
+            if (userinfoCache != null) return _mapper.Map<UserInfoDto>(userinfoCache);
+            //无缓存查库
+            var user = await _context.Users
+                .FirstOrDefaultAsync(x => x.Id == userId);
             if (user == null)
             {
                 throw new BaseException(CodeDefine.USER_NOT_FOUND);
             }
+            await _cacheService.SetUserCacheAsync(user);
             return _mapper.Map<UserInfoDto>(user);
         }
         #endregion
         #region 通过用户名获取用户信息
         public async Task<UserInfoDto> GetUserInfoByUsernameAsync(string username)
         {
+            var userinfo = await _cacheService.GetUserCacheAsync(username);
+            if (userinfo != null) return _mapper.Map<UserInfoDto>(userinfo);
             var user = await _context.Users.FirstOrDefaultAsync(x => x.Username == username);
             if (user == null)
             {
                 throw new BaseException(CodeDefine.USER_NOT_FOUND);
             }
+            await _cacheService.SetUserCacheAsync(user);
             return _mapper.Map<UserInfoDto>(user);
         }
         #endregion
@@ -70,6 +83,7 @@ namespace IM_API.Services
             if (user is null) throw new BaseException(CodeDefine.USER_NOT_FOUND);
             _mapper.Map(dto,user);
             await _context.SaveChangesAsync();
+            await _cacheService.SetUserCacheAsync(user);
             return _mapper.Map<UserInfoDto>(user);
         }
         #endregion