Add Ping backend

.NET 10 solution for Ping, a Discord style chat app: Domain, Application and Infrastructure projects plus the Api host. SignalR for chat and presence, LiveKit for call tokens, EF Core on Postgres, S3 compatible storage for attachments, and OIDC auth shared with the Musify Zitadel instance. Includes the Compose stack for local development.
2026-09-21 19:32:55 +02:00
commit 0623875dfa
126 changed files with 5048 additions and 0 deletions
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+using ErrorOr;
+using Mediator;
+using Microsoft.EntityFrameworkCore;
+using Ping.Application.Contracts;
+using Ping.Application.Messages.Responses;
+using Ping.Application.Shared;
+
+namespace Ping.Application.Messages
+{
+    public record GetChannelMessagesQuery(long CurrentUserId, Guid ChannelId, Guid? Before, int Take)
+        : IQuery<ErrorOr<List<MessageResponse>>>;
+
+    public class GetChannelMessagesQueryHandler(IDatabase database)
+        : IQueryHandler<GetChannelMessagesQuery, ErrorOr<List<MessageResponse>>>
+    {
+        private const int MaxTake = 100;
+
+        public async ValueTask<ErrorOr<List<MessageResponse>>> Handle(GetChannelMessagesQuery request, CancellationToken cancellationToken)
+        {
+            var hasAccess = await database.HasAccessAsync(request.ChannelId, request.CurrentUserId, cancellationToken);
+            if (!hasAccess)
+                return Error.NotFound(description: $"Channel {request.ChannelId} not found");
+
+            var take = Math.Clamp(request.Take, 1, MaxTake);
+
+            var query = database.Messages.AsNoTracking()
+                .Include(m => m.Author)
+                .Include(m => m.Attachments)
+                .Where(m => m.ChannelId == request.ChannelId);
+
+            if (request.Before is { } beforeId)
+            {
+                var cursorCreatedAt = await database.Messages
+                    .Where(m => m.Id == beforeId)
+                    .Select(m => m.CreatedAt)
+                    .FirstOrDefaultAsync(cancellationToken);
+
+                query = query.Where(m => m.CreatedAt < cursorCreatedAt);
+            }
+
+            var messages = await query
+                .OrderByDescending(m => m.CreatedAt)
+                .Take(take)
+                .ToListAsync(cancellationToken);
+
+            return messages.Select(MessageResponse.FromEntity).ToList();
+        }
+    }
+}