P5: downvotes, private messages from Lemmy, late Creates of deleted posts, and typed details for clients

- Dislike and its Undo are kept as downvotes (Lemmy, PieFed, Mbin, Friendica) and shown with favourites as votes.
- ChatMessage (Lemmy 0.19, Mbin, PieFed to those two) arrives as a direct message.
- A deleted object's id is remembered for 90 days, so a Create that arrives after its Delete cannot bring the post
  back; the post's ObjectRecord goes with it.
- A Join of one of our objects is answered with Ignore, as FEP-8a8e asks of a server without RSVP.
- A 503 with Retry-After is waited out like a 429 instead of counting as a failure of the host (GoToSocial throttling,
  Mastodon's temporary key failures).
- Status.privapub carries what a Mastodon Status cannot: object type, title, excerpt, cover, the author's source,
  link, video, audio and event details, and up/down votes, with every media URL proxied.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB

PrivaPub.Tests/Federation/InboundRoutingTests.cs

@@ -0,0 +1,124 @@
+using MongoDB.Entities;
+
+using PrivaPub.ClientModels.Post;
+using PrivaPub.Federation.Objects;
+using PrivaPub.Models.Post;
+using PrivaPub.Tests.Support;
+
+using System.Text.Json.Nodes;
+
+namespace PrivaPub.Tests.Federation
+{
+	[Trait("Category", "Integration")]
+	public sealed class InboundRoutingTests : IAsyncLifetime
+	{
+		Harness _harness;
+
+		public async ValueTask InitializeAsync()
+		{
+			Assert.SkipUnless(MongoFixture.Enabled, MongoFixture.Skip);
+			_harness = await Harness.Start();
+		}
+
+		public async ValueTask DisposeAsync()
+		{
+			if (_harness != default)
+				await _harness.DisposeAsync();
+		}
+
+		static string Origin(RemoteActor actor) => new Uri(actor.Id).GetLeftPart(UriPartial.Authority);
+
+		static string NewId(RemoteActor actor, string kind) => $"{Origin(actor)}/{kind}/{Guid.NewGuid():N}";
+
+		async Task<Post> LocalPost(string text)
+		{
+			var (root, alice) = await _harness.Persona("alice");
+			await _harness.Posts.InsertPost(root, new InsertPostForm { AvatarId = alice.Id, Text = text }, TestContext.Current.CancellationToken);
+			return await DB.Default.Find<Post>().Match(p => p.GroupUserId == alice.Id).ExecuteFirstAsync(TestContext.Current.CancellationToken);
+		}
+
+		[Fact]
+		public async Task A_downvote_counts_and_its_undo_takes_it_back()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var post = await LocalPost("vote on me");
+			var lemmy = new RemoteActor(_harness.Peer, "voter");
+			var dislike = new JsonObject { ["id"] = NewId(lemmy, "activities/dislike"), ["type"] = "Dislike", ["actor"] = lemmy.Id, ["object"] = post.ObjectURI };
+
+			await _harness.Deliver(lemmy, "/human-centipede", dislike);
+			Assert.Equal(1, (await DB.Default.Find<Post>().OneAsync(post.ID, token)).DownvotesCount);
+
+			await _harness.Deliver(lemmy, "/human-centipede", new JsonObject
+			{
+				["id"] = NewId(lemmy, "activities/undo"), ["type"] = "Undo", ["actor"] = lemmy.Id, ["object"] = dislike.DeepClone()
+			});
+			Assert.Equal(0, (await DB.Default.Find<Post>().OneAsync(post.ID, token)).DownvotesCount);
+		}
+
+		[Fact]
+		public async Task A_delete_that_arrives_first_keeps_the_post_from_coming_back()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var (_, alice) = await _harness.Persona("alice");
+			var mallory = new RemoteActor(_harness.Peer, "mallory");
+			var noteId = NewId(mallory, "notes");
+
+			await _harness.Deliver(mallory, "/human-centipede", new JsonObject
+			{
+				["id"] = NewId(mallory, "activities/delete"), ["type"] = "Delete", ["actor"] = mallory.Id,
+				["object"] = new JsonObject { ["id"] = noteId, ["type"] = "Tombstone" }
+			});
+			await _harness.Deliver(mallory, "/human-centipede", new JsonObject
+			{
+				["id"] = NewId(mallory, "activities/create"), ["type"] = "Create", ["actor"] = mallory.Id,
+				["object"] = new JsonObject
+				{
+					["id"] = noteId, ["type"] = "Note", ["attributedTo"] = mallory.Id, ["content"] = "<p>late</p>",
+					["to"] = new JsonArray(Addressing.Public), ["cc"] = new JsonArray(alice.Uri),
+					["tag"] = new JsonArray(new JsonObject { ["type"] = "Mention", ["href"] = alice.Uri, ["name"] = "@alice" })
+				}
+			});
+
+			Assert.False(await DB.Default.Find<Post>().Match(p => p.ObjectURI == noteId).ExecuteAnyAsync(token));
+		}
+
+		[Fact]
+		public async Task A_lemmy_private_message_arrives_as_a_direct_message()
+		{
+			var token = TestContext.Current.CancellationToken;
+			var (_, alice) = await _harness.Persona("alice");
+			var lemmy = new RemoteActor(_harness.Peer, "pm");
+			var messageId = NewId(lemmy, "private_message");
+
+			await _harness.Deliver(lemmy, "/human-centipede", new JsonObject
+			{
+				["id"] = NewId(lemmy, "activities/create"), ["type"] = "Create", ["actor"] = lemmy.Id, ["to"] = new JsonArray(alice.Uri),
+				["object"] = new JsonObject
+				{
+					["id"] = messageId, ["type"] = "ChatMessage", ["attributedTo"] = lemmy.Id, ["to"] = new JsonArray(alice.Uri),
+					["content"] = "<p>psst</p>", ["mediaType"] = "text/html", ["published"] = DateTime.UtcNow.ToString("O")
+				}
+			});
+
+			var message = await DB.Default.Find<Post>().Match(p => p.ObjectURI == messageId).ExecuteFirstAsync(token);
+			Assert.NotNull(message);
+			Assert.Equal(PostVisibility.Direct, message.Visibility);
+			Assert.NotNull(message.ConversationId);
+		}
+
+		[Fact]
+		public async Task A_join_of_a_local_post_is_answered_with_ignore()
+		{
+			var post = await LocalPost("not an event");
+			var mobilizon = new RemoteActor(_harness.Peer, "joiner");
+
+			await _harness.Deliver(mobilizon, "/human-centipede", new JsonObject
+			{
+				["id"] = NewId(mobilizon, "join"), ["type"] = "Join", ["actor"] = mobilizon.Id, ["object"] = post.ObjectURI
+			});
+
+			var answer = Assert.Single(await _harness.Outgoing(mobilizon.Id + "/inbox"));
+			Assert.Equal("Ignore", answer["type"]!.GetValue<string>());
+		}
+	}
+}

PrivaPub.Tests/Support/Harness.cs

@@ -53,6 +53,8 @@ namespace PrivaPub.Tests.Support
 				new RejectHandler(Db, Local),
 				new UndoHandler(Db, Local),
 				new LikeHandler(Db),
+				new DislikeHandler(Db),
+				new JoinHandler(Db, Local, Delivery),
 				new AnnounceHandler(Db, Local, RemotePosts, Fanout, Remote),
 				new CreateHandler(Db, Local, Remote, Delivery, new NoBlocks(), Fanout, RemotePosts, Groups, Records),
 				new DeleteHandler(Db, Local, Remote, Delivery, Groups),