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/Dtos/Auth/LoginDto.cs

@@ -1,18 +0,0 @@
-using IM_API.Dtos.User;
-
-namespace IM_API.Dtos.Auth
-{
-    public class LoginDto
-    {
-        public UserInfoDto userInfo { get; set; }
-        public string Token { get; set; }
-        public string RefreshToken { get; set; }
-        public DateTime ExpireAt { get; set; }
-        public LoginDto(UserInfoDto userInfo,string token, string refreshToken, DateTime expireAt) { 
-            this.userInfo = userInfo;
-            Token = token;
-            RefreshToken = refreshToken;
-            ExpireAt = expireAt;
-        }
-    }
-}

backend/IM_API/Dtos/Conversation/ConversationDto.cs

@@ -1,51 +0,0 @@
-using IM_API.Models;
-
-namespace IM_API.Dtos.Conversation
-{
-    public class ConversationDto
-    {
-        public int Id { get; set; }
-
-        /// <summary>
-        /// 用户
-        /// </summary>
-        public int UserId { get; set; }
-
-        /// <summary>
-        /// 对方ID（群聊为群聊ID，单聊为单聊ID）	
-        /// </summary>
-        public int TargetId { get; set; }
-
-        /// <summary>
-        /// 最后一条未读消息ID	
-        /// </summary>
-        public int? LastReadMessageId { get; set; }
-
-        /// <summary>
-        /// 未读消息数	
-        /// </summary>
-        public int UnreadCount { get; set; }
-
-        public int ChatType { get; set; }
-
-
-        /// <summary>
-        /// 最后一条最新消息
-        /// </summary>
-        public string LastMessage { get; set; } = null!;
-        /// <summary>
-        /// 最后一条消息时间
-        /// </summary>
-        public DateTime? DateTime { get; set; } = null;
-
-        /// <summary>
-        /// 对方昵称
-        /// </summary>
-        public string TargetName { get; set; }
-        /// <summary>
-        /// 对方头像
-        /// </summary>
-        public string? TargetAvatar { get; set; }
-        public MessageBaseDto? LastReadMessage { get; set; }
-    }
-}

backend/IM_API/Dtos/Conversation/UpdateConversationDto.cs

@@ -0,0 +1,12 @@
+namespace IM_API.Dtos.Conversation
+{
+    public class UpdateConversationDto
+    {
+        public string StreamKey { get; set; }
+        public int SenderId { get; set; }
+        public int ReceiptId { get; set; }
+        public string LastMessage { get; set; }
+        public long LastSequenceId { get; set; }
+        public DateTimeOffset DateTime { get; set; }
+    }
+}

backend/IM_API/Dtos/Friend/FriendDto.cs

@@ -14,7 +14,7 @@ namespace IM_API.Dtos.Friend
 
         public FriendStatus StatusEnum { get; init; }
 
-        public DateTime Created { get; init; }
+        public DateTimeOffset Created { get; init; }
 
         public string RemarkName { get; init; } = string.Empty;
 

backend/IM_API/Dtos/Friend/FriendRequestResDto.cs

@@ -21,7 +21,7 @@ namespace IM_API.Dtos.Friend
         /// <summary>
         /// 申请时间	
         /// </summary>
-        public DateTime Created { get; set; }
+        public DateTimeOffset Created { get; set; }
 
         /// <summary>
         /// 申请附言	

backend/IM_API/Dtos/Group/GroupCreateDto.cs

@@ -1,4 +1,5 @@
 using IM_API.Models;
+using System.ComponentModel.DataAnnotations;
 
 namespace IM_API.Dtos.Group
 {
@@ -7,11 +8,15 @@ namespace IM_API.Dtos.Group
         /// <summary>
         /// 群聊名称
         /// </summary>
+        [Required(ErrorMessage = "群名称必填")]
+        [MaxLength(20, ErrorMessage = "群名称不能大于20字符")]
         public string Name { get; set; } = null!;
 
         /// <summary>
         /// 群头像
         /// </summary>
+        [Required(ErrorMessage = "群头像必填")]
         public string Avatar { get; set; } = null!;
+        public List<int>? UserIDs { get; set; }
     }
 }

backend/IM_API/Dtos/Group/GroupInfoDto.cs

@@ -41,7 +41,7 @@ namespace IM_API.Dtos.Group
         /// <summary>
         /// 群聊创建时间
         /// </summary>
-        public DateTime Created { get; set; }
+        public DateTimeOffset Created { get; set; }
 
         /// <summary>
         /// 群头像

backend/IM_API/Dtos/HubResponse.cs

@@ -14,6 +14,7 @@ namespace IM_API.Dtos
             Code = CodeDefine.SUCCESS.Code;
             Message = CodeDefine.SUCCESS.Message;
             Type = HubResponseType.ActionStatus;
+            Method = method;
         }
         public HubResponse(string method,T data)
         {
@@ -21,6 +22,7 @@ namespace IM_API.Dtos
             Message = CodeDefine.SUCCESS.Message;
             Type = HubResponseType.ActionStatus;
             Data = data;
+            Method = method;
         }
         public HubResponse(CodeDefine codedefine,string method)
         {

backend/IM_API/Dtos/Message/MessageQueryDto.cs

@@ -0,0 +1,18 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace IM_API.Dtos.Message
+{
+    public class MessageQueryDto
+    {
+        [Required(ErrorMessage = "会话ID必填")]
+        public int ConversationId { get; set; }
+
+        // 锚点序号（如果为空，说明是第一次进聊天框，拉最新的）
+        public long? Cursor { get; set; }
+
+        // 查询方向：0 - 查旧(Before), 1 - 查新(After)
+        public int Direction { get; set; } = 0;
+
+        public int Limit { get; set; } = 20;
+    }
+}

backend/IM_API/Dtos/MessageDto.cs

@@ -7,12 +7,11 @@ namespace IM_API.Dtos
         // 使用 { get; init; } 确保对象创建后不可修改，且支持无参构造
         public MessageMsgType Type { get; init; } = default!;
         public ChatType ChatType { get; init; } = default!;
-        public string? MsgId { get; init; }
+        public Guid MsgId { get; init; }
         public int SenderId { get; init; }
         public int ReceiverId { get; init; }
-        public int? GroupMemberId { get; init; }
         public string Content { get; init; } = default!;
-        public DateTime TimeStamp { get; init; }
+        public DateTimeOffset TimeStamp { get; init; }
         public MessageBaseDto() { }
     }
 }

backend/IM_API/Dtos/User/UserInfoDto.cs

@@ -32,7 +32,7 @@ namespace IM_API.Dtos.User
         /// <summary>
         /// 创建时间
         /// </summary>
-        public DateTime Created { get; set; }
+        public DateTimeOffset Created { get; set; }
 
         /// <summary>
         /// 账户状态