通知中心游标分页

src/Jiaowu.Api/Controllers/NotificationsController.cs

@@ -213,7 +213,7 @@ public sealed class NotificationsController(
         Guid? administrativeClassId,
         Guid? teachingTaskId,
         string? keyword,
-        int page = 1,
+        string? cursor = null,
         int pageSize = 30,
         CancellationToken cancellationToken = default)
     {
@@ -241,17 +241,22 @@ public sealed class NotificationsController(
         if (filter.Role is not null && !SystemRoles.All.Contains(filter.Role))
             return ValidationProblem("所选身份类型无效。");
 
-        page = Math.Max(1, page);
         pageSize = Math.Clamp(pageSize, 10, 100);
+        if (!CursorToken.TryDecode<RecipientCursor>(cursor, out var after))
+            return BadRequest("收件人游标无效。");
         var source = ApplyRecipientFilter(
             ScopedRecipientQuery(scope, resolvedCollegeId),
             filter);
         var total = await source.CountAsync(cancellationToken);
+        if (after is not null)
+        {
+            source = source.Where(x => x.DisplayName.CompareTo(after.DisplayName) > 0 ||
+                x.DisplayName == after.DisplayName && x.Id.CompareTo(after.Id) > 0);
+        }
         var users = await source
             .OrderBy(x => x.DisplayName)
-            .ThenBy(x => x.UserName)
-            .Skip((page - 1) * pageSize)
-            .Take(pageSize)
+            .ThenBy(x => x.Id)
+            .Take(pageSize + 1)
             .Select(user => new
             {
                 user.Id,
@@ -276,6 +281,8 @@ public sealed class NotificationsController(
                     .FirstOrDefault()
             })
             .ToListAsync(cancellationToken);
+        var hasMore = users.Count > pageSize;
+        users = users.Take(pageSize).ToList();
         var userIds = users.Select(x => x.Id).ToArray();
         var roleRows = await db.UserRoles.AsNoTracking()
             .Where(x => userIds.Contains(x.UserId))
@@ -295,6 +302,7 @@ public sealed class NotificationsController(
                 group => group.Key,
                 group => group.Select(x => x.RoleName).Distinct().ToArray());
 
+        var last = users.LastOrDefault();
         return Ok(new
         {
             Items = users.Select(user => new
@@ -308,11 +316,16 @@ public sealed class NotificationsController(
                 Roles = rolesByUser.GetValueOrDefault(user.Id, [])
             }),
             Total = total,
-            Page = page,
+            HasMore = hasMore,
+            NextCursor = hasMore && last is not null
+                ? CursorToken.Encode(new RecipientCursor(last.DisplayName, last.Id))
+                : null,
             PageSize = pageSize
         });
     }
 
+    private sealed record RecipientCursor(string DisplayName, Guid Id);
+
     [HttpPost("send")]
     [Authorize(Roles = Senders)]
     public async Task<ActionResult> Send(
@@ -485,20 +498,24 @@ public sealed class NotificationsController(
     [HttpGet("sent")]
     [Authorize(Roles = Senders)]
     public async Task<ActionResult> GetSent(
-        int page = 1,
+        string? cursor = null,
         int pageSize = 20,
         CancellationToken cancellationToken = default)
     {
-        page = Math.Max(1, page);
         pageSize = Math.Clamp(pageSize, 1, 100);
+        if (!CursorToken.TryDecode<NotificationCursor>(cursor, out var after))
+            return BadRequest("已发送消息游标无效。");
         var userId = currentUserDataScope.Current.UserId;
         var source = db.MessageDispatches.AsNoTracking()
             .Where(x => x.SenderUserId == userId);
-        var total = await source.CountAsync(cancellationToken);
-        var items = await source
-            .OrderByDescending(x => x.CreatedAt)
-            .Skip((page - 1) * pageSize)
-            .Take(pageSize)
+        if (after is not null)
+        {
+            source = source.Where(x => x.CreatedAt < after.CreatedAt ||
+                x.CreatedAt == after.CreatedAt && x.Id.CompareTo(after.Id) < 0);
+        }
+        var rows = await source
+            .OrderByDescending(x => x.CreatedAt).ThenByDescending(x => x.Id)
+            .Take(pageSize + 1)
             .Select(x => new
             {
                 x.Id,
@@ -511,7 +528,18 @@ public sealed class NotificationsController(
                 x.CreatedAt
             })
             .ToListAsync(cancellationToken);
-        return Ok(new { Items = items, Total = total });
+        var hasMore = rows.Count > pageSize;
+        var items = rows.Take(pageSize).ToArray();
+        var last = items.LastOrDefault();
+        return Ok(new
+        {
+            Items = items,
+            HasMore = hasMore,
+            NextCursor = hasMore && last is not null
+                ? CursorToken.Encode(new NotificationCursor(last.CreatedAt, last.Id))
+                : null,
+            PageSize = pageSize
+        });
     }
 
     [HttpPost("{id:guid}/read")]

src/Jiaowu.Api/Controllers/WarningsController.cs

@@ -138,15 +138,17 @@ public sealed class WarningsController(AppDbContext db, ICurrentUserDataScope sc
 
     [HttpGet("records")]
     [Authorize(Roles = Managers + "," + SystemRoles.Counselor)]
-    public async Task<ActionResult<PagedResult<WarningRecordListItem>>> GetRecords(
+    public async Task<ActionResult<CursorPagedResult<WarningRecordListItem>>> GetRecords(
         Guid? academicTermId,
         WarningType? type,
-        int page = 1,
+        string? cursor = null,
         int pageSize = 20,
         CancellationToken ct = default)
     {
-        if (page < 1 || pageSize is < 1 or > 100)
-            return ValidationProblem("页码必须大于 0，且每页条数应在 1 至 100 之间。");
+        if (pageSize is < 1 or > 100)
+            return ValidationProblem("每批条数应在 1 至 100 之间。");
+        if (!CursorToken.TryDecode<WarningCursor>(cursor, out var after))
+            return BadRequest("预警记录游标无效。");
 
         var q = db.WarningRecords.AsNoTracking().AsQueryable();
         if (scope.Current.Scope == DataScope.College || scope.Current.IsInRole(SystemRoles.Counselor))
@@ -160,12 +162,15 @@ public sealed class WarningsController(AppDbContext db, ICurrentUserDataScope sc
         if (academicTermId.HasValue) q = q.Where(x => x.AcademicTermId == academicTermId);
         if (type.HasValue) q = q.Where(x => x.Type == type);
 
-        var total = await q.CountAsync(ct);
-        var items = await q
+        if (after is not null)
+        {
+            q = q.Where(x => x.CreatedAt < after.CreatedAt ||
+                x.CreatedAt == after.CreatedAt && x.Id.CompareTo(after.Id) < 0);
+        }
+        var rows = await q
             .OrderByDescending(x => x.CreatedAt)
             .ThenByDescending(x => x.Id)
-            .Skip((page - 1) * pageSize)
-            .Take(pageSize)
+            .Take(pageSize + 1)
             .Select(x => new WarningRecordListItem(
                 x.Id,
                 x.StudentId,
@@ -180,9 +185,20 @@ public sealed class WarningsController(AppDbContext db, ICurrentUserDataScope sc
                 x.AcknowledgeComment,
                 x.CreatedAt))
             .ToListAsync(ct);
-        return Ok(new PagedResult<WarningRecordListItem>(items, total, page, pageSize));
+        var hasMore = rows.Count > pageSize;
+        var items = rows.Take(pageSize).ToArray();
+        var last = items.LastOrDefault();
+        return Ok(new CursorPagedResult<WarningRecordListItem>(
+            items,
+            hasMore && last is not null
+                ? CursorToken.Encode(new WarningCursor(last.CreatedAt, last.Id))
+                : null,
+            hasMore,
+            pageSize));
     }
 
+    private sealed record WarningCursor(DateTime CreatedAt, Guid Id);
+
     // ═══════════ Student ═══════════
     [HttpGet("my-warnings")]
     [Authorize(Roles = SystemRoles.Student)]