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/Models/Admin.cs

@@ -30,12 +30,12 @@ public partial class Admin
     /// <summary>
     /// 创建时间	
     /// </summary>
-    public DateTime Created { get; set; }
+    public DateTimeOffset Created { get; set; }
 
     /// <summary>
     /// 更新时间	
     /// </summary>
-    public DateTime Updated { get; set; }
+    public DateTimeOffset Updated { get; set; }
 
     public virtual Role Role { get; set; } = null!;
 }

backend/IM_API/Models/Conversation.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -20,14 +21,14 @@ public partial class Conversation
     /// <summary>
     /// 最后一条未读消息ID	
     /// </summary>
-    public int? LastReadMessageId { get; set; }
+    public long? LastReadSequenceId { get; set; }
 
     /// <summary>
     /// 未读消息数	
     /// </summary>
     public int UnreadCount { get; set; }
 
-    public int ChatType { get; set; }
+    public ChatType ChatType { get; set; }
 
     /// <summary>
     /// 消息推送唯一标识符
@@ -42,9 +43,9 @@ public partial class Conversation
     /// <summary>
     /// 最后一条消息发送时间
     /// </summary>
-    public DateTime LastMessageTime { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset LastMessageTime { get; set; }
 
-    public virtual Message? LastReadMessage { get; set; }
 
     public virtual User User { get; set; } = null!;
 }

backend/IM_API/Models/ConversationExt.cs

@@ -0,0 +1,18 @@
+using IM_API.Dtos.Conversation;
+
+namespace IM_API.Models
+{
+    public partial class Conversation
+    {
+        public ChatType ChatTypeEnum {
+            get
+            {
+                return ChatType;
+            }
+            set
+            {
+                ChatType = value;
+            }
+        }
+    }
+}

backend/IM_API/Models/Device.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -21,7 +22,8 @@ public partial class Device
     /// <summary>
     /// 最后一次登录	
     /// </summary>
-    public DateTime LastLogin { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset LastLogin { get; set; }
 
     public virtual User User { get; set; } = null!;
 }

backend/IM_API/Models/File.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -25,7 +26,7 @@ public partial class File
     /// <summary>
     /// 文件类型	
     /// </summary>
-    public string Type { get; set; } = null!;
+    public string FileType { get; set; } = null!;
 
     /// <summary>
     /// 关联消息ID	
@@ -35,7 +36,8 @@ public partial class File
     /// <summary>
     /// 创建时间	
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     public virtual Message Message { get; set; } = null!;
 }

backend/IM_API/Models/Friend.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -26,7 +27,8 @@ public partial class Friend
     /// <summary>
     /// 好友关系创建时间
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     /// <summary>
     /// 好友备注名

backend/IM_API/Models/Friendrequest.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -20,7 +21,8 @@ public partial class FriendRequest
     /// <summary>
     /// 申请时间	
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     /// <summary>
     /// 申请附言	

backend/IM_API/Models/Group.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -42,7 +43,8 @@ public partial class Group
     /// <summary>
     /// 群聊创建时间
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     /// <summary>
     /// 群头像

backend/IM_API/Models/Groupinvite.cs

@@ -31,7 +31,7 @@ public partial class GroupInvite
     /// <summary>
     /// 创建时间
     /// </summary>
-    public DateTime? Created { get; set; }
+    public DateTimeOffset? Created { get; set; }
 
     public virtual Group Group { get; set; } = null!;
 

backend/IM_API/Models/Groupmember.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -25,7 +26,8 @@ public partial class GroupMember
     /// <summary>
     /// 加入群聊时间
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     public virtual Group Group { get; set; } = null!;
 

backend/IM_API/Models/Grouprequest.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -31,7 +32,8 @@ public partial class GroupRequest
     /// <summary>
     /// 创建时间
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     public virtual Group Group { get; set; } = null!;
 

backend/IM_API/Models/ImContext.Custom.cs

@@ -19,7 +19,7 @@ namespace IM_API.Models
             });
             modelBuilder.Entity<Conversation>(entity =>
             {
-
+                entity.Ignore(e => e.ChatTypeEnum);
             });
 
             modelBuilder.Entity<Device>(entity =>

backend/IM_API/Models/ImContext.cs

@@ -101,7 +101,8 @@ public partial class ImContext : DbContext
 
             entity.HasIndex(e => e.UserId, "Userid");
 
-            entity.HasIndex(e => e.LastReadMessageId, "lastMessageId");
+            entity.HasIndex(e => e.LastReadSequenceId, "LastReadSequenceId");
+
 
             entity.Property(e => e.Id)
                 .HasColumnType("int(11)")
@@ -113,7 +114,7 @@ public partial class ImContext : DbContext
             entity.Property(e => e.LastMessageTime)
                 .HasComment("最后一条消息发送时间")
                 .HasColumnType("datetime");
-            entity.Property(e => e.LastReadMessageId)
+            entity.Property(e => e.LastReadSequenceId)
                 .HasComment("最后一条未读消息ID	")
                 .HasColumnType("int(11)")
                 .HasColumnName("lastReadMessageId");
@@ -130,10 +131,6 @@ public partial class ImContext : DbContext
                 .HasComment("用户")
                 .HasColumnType("int(11)");
 
-            entity.HasOne(d => d.LastReadMessage).WithMany(p => p.Conversations)
-                .HasForeignKey(d => d.LastReadMessageId)
-                .HasConstraintName("conversations_ibfk_2");
-
             entity.HasOne(d => d.User).WithMany(p => p.Conversations)
                 .HasForeignKey(d => d.UserId)
                 .OnDelete(DeleteBehavior.ClientSetNull)
@@ -197,7 +194,7 @@ public partial class ImContext : DbContext
             entity.Property(e => e.Size)
                 .HasComment("文件大小（单位：KB）	")
                 .HasColumnType("int(11)");
-            entity.Property(e => e.Type)
+            entity.Property(e => e.FileType)
                 .HasMaxLength(10)
                 .HasComment("文件类型	");
             entity.Property(e => e.Url)
@@ -529,6 +526,11 @@ public partial class ImContext : DbContext
 
             entity.HasIndex(e => e.Sender, "Sender");
 
+            
+            //设置联合唯一索引
+            entity.HasIndex(e => new { e.SequenceId, e.StreamKey })
+            .IsUnique();
+
             entity.Property(e => e.Id)
                 .HasColumnType("int(11)")
                 .HasColumnName("ID");
@@ -541,9 +543,6 @@ public partial class ImContext : DbContext
             entity.Property(e => e.Created)
                 .HasComment("发送时间	")
                 .HasColumnType("datetime");
-            entity.Property(e => e.GroupMemberId)
-                .HasComment("若为群消息则表示具体的成员id")
-                .HasColumnType("int(11)");
             entity.Property(e => e.MsgType)
                 .HasComment("消息类型\r\n(0:文本,1：图片,2：语音,3：视频,4：文件，5：语音聊天,6：视频聊天)")
                 .HasColumnType("tinyint(4)");

backend/IM_API/Models/LoginLog.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -15,7 +16,8 @@ public partial class LoginLog
     /// <summary>
     /// 登录时间	
     /// </summary>
-    public DateTime Logined { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Logined { get; set; }
 
     /// <summary>
     /// 登录用户	

backend/IM_API/Models/Message.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -18,6 +19,7 @@ public partial class Message
     /// (0:文本,1：图片,2：语音,3：视频,4：文件，5：语音聊天,6：视频聊天)
     /// </summary>
     public sbyte MsgType { get; set; }
+    public Guid ClientMsgId { get; set; }
 
     /// <summary>
     /// 消息内容	
@@ -42,7 +44,8 @@ public partial class Message
     /// <summary>
     /// 发送时间	
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     /// <summary>
     /// 消息推送唯一标识符
@@ -50,9 +53,10 @@ public partial class Message
     public string StreamKey { get; set; } = null!;
 
     /// <summary>
-    /// 若为群消息则表示具体的成员id
+    /// 消息排序标识
     /// </summary>
-    public int? GroupMemberId { get; set; }
+
+    public long SequenceId { get; set; }
 
     public virtual ICollection<Conversation> Conversations { get; set; } = new List<Conversation>();
 

backend/IM_API/Models/Notification.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -30,7 +31,8 @@ public partial class Notification
     /// <summary>
     /// 创建时间
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     public virtual User User { get; set; } = null!;
 }

backend/IM_API/Models/Permission.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -25,7 +26,8 @@ public partial class Permission
     /// <summary>
     /// 创建时间	
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     public virtual ICollection<Permissionarole> Permissionaroles { get; set; } = new List<Permissionarole>();
 }

backend/IM_API/Models/Role.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -20,7 +21,8 @@ public partial class Role
     /// <summary>
     /// 创建时间	
     /// </summary>
-    public DateTime Created { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset Created { get; set; }
 
     public virtual ICollection<Admin> Admins { get; set; } = new List<Admin>();
 

backend/IM_API/Models/User.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations.Schema;
 
 namespace IM_API.Models;
 
@@ -32,12 +33,13 @@ public partial class User
     /// <summary>
     /// 创建时间
     /// </summary>
-    public DateTime Created { get; set; }
+    public DateTimeOffset Created { get; set; }
 
     /// <summary>
     /// 修改时间
     /// </summary>
-    public DateTime? Updated { get; set; }
+    [Column(TypeName = "datetimeoffset")]
+    public DateTimeOffset? Updated { get; set; }
 
     /// <summary>
     /// 账户状态