M6: provenance fixes, stored features, community edits that are real edits

- A fetched ObjectRecord no longer wears the signature, key, signed headers and @context
  of the activity that caused the fetch, and its ReceivedAt is the fetch's own time. Its
  activity fields now name the trigger. Provenance answers signature null and
  fetchedBy "instance-actor". Migration _008 clears the old fetched records.
- ObjectRecords store their ObjectFeatures extensions and context namespaces (migration
  _009 fills older records in batches), so statistics can count them. Provenance reads the
  stored lists.
- ForeignAvatar.Features records what an actor document uses (ActorFeatures): featured,
  shared inbox, FEP-521a, FEP-8b32, identity proofs, Misskey fields, indexable,
  undiscoverable, locked, key size, and more.
- RemoteEdits.Apply and RemoteDeletes.Remove are shared by the Update, Delete and Announce
  handlers. A community-wrapped Update is now an edit only when newer, refreshes polls
  and media otherwise, revises the ObjectRecord and re-resolves quotes. A
  community-wrapped Delete now tombstones the object, removes its ObjectRecord, reblogs
  and timeline rows, and lowers the reply count. Any deleted quoting post lowers the
  quoted post's quote count.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ELjqpznMFMNrJoJUj6K5p2

PrivaPub/Federation/Actors/ActorDocument.cs

@@ -37,6 +37,7 @@ namespace PrivaPub.Federation.Actors
 		public List<CustomEmoji> Emojis { get; init; } = new();
 		public Dictionary<string, string> Fields { get; init; } = new();
 		public IReadOnlyList<ActorKey> Keys { get; init; } = Array.Empty<ActorKey>();
+		public List<string> Features { get; init; } = new();
 
 		public ActorKey Key(string keyId) => Keys.FirstOrDefault(k => k.Id == keyId);
 
@@ -54,6 +55,7 @@ namespace PrivaPub.Federation.Actors
 			{
 				Id = id,
 				Type = type,
+				Features = ActorFeatures.Detect(root),
 				PreferredUsername = RemoteActorService.Text(root, "preferredUsername"),
 				Name = RemoteActorService.Text(root, "name"),
 				Summary = RemoteActorService.Text(root, "summary"),

PrivaPub/Federation/Actors/ActorFeatures.cs

@@ -0,0 +1,72 @@
+using System.Security.Cryptography;
+using System.Text.Json;
+
+namespace PrivaPub.Federation.Actors
+{
+	public static class ActorFeatures
+	{
+		public static List<string> Detect(JsonElement root)
+		{
+			var found = new List<string>();
+			if (root.ValueKind != JsonValueKind.Object)
+				return found;
+			void When(bool condition, string feature)
+			{
+				if (condition)
+					found.Add(feature);
+			}
+			bool Has(string name) => root.TryGetProperty(name, out var value) && value.ValueKind is not (JsonValueKind.Null or JsonValueKind.Undefined);
+			bool True(string name) => root.TryGetProperty(name, out var value) && value.ValueKind == JsonValueKind.True;
+			IEnumerable<JsonElement> Items(string name) => !root.TryGetProperty(name, out var value)
+				? Enumerable.Empty<JsonElement>()
+				: value.ValueKind == JsonValueKind.Array ? value.EnumerateArray() : new[] { value };
+			bool Typed(JsonElement item, string type) =>
+				item.ValueKind == JsonValueKind.Object && item.TryGetProperty("type", out var t) && t.ValueKind == JsonValueKind.String && t.GetString() == type;
+
+			When(Has("featured"), "featured");
+			When(Has("featuredTags"), "featured-tags");
+			When(Items("alsoKnownAs").Any(), "also-known-as");
+			When(Has("movedTo"), "moved-to");
+			When(root.TryGetProperty("endpoints", out var endpoints) && endpoints.ValueKind == JsonValueKind.Object && endpoints.TryGetProperty("sharedInbox", out _), "shared-inbox");
+			When(Has("assertionMethod"), "fep-521a-assertion-method");
+			When(Has("proof"), "fep-8b32-proof");
+			When(Items("attachment").Any(a => Typed(a, "PropertyValue")), "property-value");
+			When(Items("attachment").Any(a => Typed(a, "VerifiableIdentityStatement") || Typed(a, "IdentityProof")), "fep-c390-identity-proof");
+			When(Items("tag").Any(t => Typed(t, "Emoji")), "custom-emoji");
+			When(root.EnumerateObject().Any(p => p.Name.StartsWith("_misskey", StringComparison.Ordinal)), "misskey");
+			When(True("isCat"), "is-cat");
+			When(Has("webfinger"), "fep-2c59-webfinger");
+			When(Has("attributionDomains"), "attribution-domains");
+			When(Has("searchableBy"), "fep-268d-searchable-by");
+			When(True("indexable"), "indexable");
+			When(root.TryGetProperty("discoverable", out var discoverable) && discoverable.ValueKind == JsonValueKind.False, "undiscoverable");
+			When(True("manuallyApprovesFollowers"), "locked");
+			When(True("memorial"), "memorial");
+			When(Has("generator"), "generator");
+			When(root.TryGetProperty("publicKey", out var keys) && keys.ValueKind == JsonValueKind.Array, "public-key-array");
+			if (KeyBits(root) is { } bits)
+				found.Add($"key:rsa-{bits}");
+			return found;
+		}
+
+		static int? KeyBits(JsonElement root)
+		{
+			if (!root.TryGetProperty("publicKey", out var key))
+				return default;
+			if (key.ValueKind == JsonValueKind.Array)
+				key = key.EnumerateArray().FirstOrDefault(k => k.ValueKind == JsonValueKind.Object);
+			if (key.ValueKind != JsonValueKind.Object || !key.TryGetProperty("publicKeyPem", out var pem) || pem.ValueKind != JsonValueKind.String)
+				return default;
+			try
+			{
+				using var rsa = RSA.Create();
+				rsa.ImportFromPem(pem.GetString());
+				return rsa.KeySize;
+			}
+			catch (Exception ex) when (ex is ArgumentException or CryptographicException)
+			{
+				return default;
+			}
+		}
+	}
+}

PrivaPub/Federation/Actors/RemoteActorService.cs

@@ -192,6 +192,7 @@ namespace PrivaPub.Federation.Actors
 				.Modify(a => a.Published, actor.Published)
 				.Modify(a => a.Emojis, actor.Emojis)
 				.Modify(a => a.Fields, actor.Fields)
+				.Modify(a => a.Features, actor.Features)
 				.Modify(a => a.AvatarType, Enum.TryParse<AvatarType>(actor.Type, out var type) ? type : AvatarType.Person)
 				.Modify(a => a.PublicKeyId, key?.Id)
 				.Modify(a => a.PublicKey, key?.Pem)

PrivaPub/Federation/Inbox/Handlers/AnnounceHandler.cs

@@ -1,6 +1,7 @@
 using MongoDB.Driver;
 using MongoDB.Entities;
 
+using PrivaPub.Domain.Statuses;
 using PrivaPub.Domain.Social;
 using PrivaPub.Domain.Timelines;
 using PrivaPub.Federation.Actors;
@@ -28,8 +29,14 @@ namespace PrivaPub.Federation.Inbox.Handlers
 		readonly IFanout _fanout;
 		readonly IRemoteActorService _remoteActors;
 
-		public AnnounceHandler(DbEntities dbEntities, ILocalActorService localActors, IRemotePosts remotePosts, IFanout fanout, IRemoteActorService remoteActors)
+		readonly IObjectRecords _records;
+		readonly IQuoteService _quotes;
+
+		public AnnounceHandler(DbEntities dbEntities, ILocalActorService localActors, IRemotePosts remotePosts, IFanout fanout, IRemoteActorService remoteActors,
+			IObjectRecords records, IQuoteService quotes)
 		{
+			_records = records;
+			_quotes = quotes;
 			_remoteActors = remoteActors;
 			_dbEntities = dbEntities;
 			_localActors = localActors;
@@ -172,24 +179,7 @@ namespace PrivaPub.Federation.Inbox.Handlers
 							Arrival.Drop(note == default ? "fetch-failed" : "misattributed");
 							return;
 						}
-						Arrival.Accept("edit");
-						stored.Revisions.Add(new PostRevision
-						{
-							Title = stored.Title,
-							SpoilerText = stored.SpoilerText,
-							ContentHtml = stored.ContentHtml,
-							HasContentWarning = stored.HasContentWarning,
-							EditedAt = stored.EditedAt ?? stored.CreationDate
-						});
-						stored.Title = note.Title;
-						stored.SpoilerText = note.SpoilerText;
-						stored.HasContentWarning = note.Sensitive;
-						stored.Text = note.ContentHtml;
-						stored.ContentHtml = note.ContentHtml;
-						stored.Tags = note.Tags.ToList();
-						stored.Media = note.Attachments.ToList();
-						stored.EditedAt = note.Updated ?? DateTime.UtcNow;
-						await DB.Default.SaveAsync(stored, token);
+						Arrival.Accept(await RemoteEdits.Apply(stored, note, Id(inner), _localActors, _records, _quotes, token) ? "edit" : "refresh");
 					}
 					break;
 				case "Delete" when objectUri != default:
@@ -207,8 +197,7 @@ namespace PrivaPub.Federation.Inbox.Handlers
 							return;
 						}
 					Arrival.Accept("removed");
-					await DB.Default.DeleteAsync<PostEntity>(deleted.ID);
-					await DB.Default.DeleteAsync<TimelineEntry>(e => e.PostId == deleted.ID);
+					await RemoteDeletes.Remove(deleted, objectUri, token);
 					break;
 				default:
 					Arrival.Drop("unsupported");

PrivaPub/Federation/Inbox/Handlers/DeleteHandler.cs

@@ -73,11 +73,7 @@ namespace PrivaPub.Federation.Inbox.Handlers
 				return;
 			}
 
-			await DB.Default.Update<DeletedObject>()
-				.Match(d => d.ObjectURI == objectUri)
-				.Modify(d => d.DeletedAt, DateTime.UtcNow)
-				.Option(o => o.IsUpsert = true)
-				.ExecuteAsync(token);
+			await RemoteDeletes.Tombstone(objectUri, token);
 			var post = await _dbEntities.Posts.Match(p => p.ObjectURI == objectUri && p.ActorURI == actor.ActorURI).ExecuteFirstAsync(token);
 			if (post == default)
 			{
@@ -87,14 +83,9 @@ namespace PrivaPub.Federation.Inbox.Handlers
 			}
 			Arrival.Accept("removed");
 			Arrival.About(post.ObjectType, post.Visibility, post.CreationDate);
-			await DB.Default.DeleteAsync<PostEntity>(post.ID);
-			await DB.Default.DeleteAsync<ObjectRecord>(r => r.PostId == post.ID || r.ObjectURI == objectUri);
-			await DB.Default.DeleteAsync<TimelineEntry>(e => e.PostId == post.ID || e.ReblogOfPostId == post.ID);
+			await RemoteDeletes.Remove(post, objectUri, token);
 			if (!string.IsNullOrEmpty(post.GroupId) && await _localActors.FindById(LocalActorKind.Group, post.GroupId, token) is { IsCircle: false } community)
 				await _groups.Announce(community, activity.AsObject(), post.ObjectURI, isNewPost: false, token);
-			await DB.Default.DeleteAsync<PostEntity>(p => p.ReblogOfPostId == post.ID);
-			if (!string.IsNullOrEmpty(post.AnsweringToPostId))
-				await DB.Default.Update<PostEntity>().MatchID(post.AnsweringToPostId).Modify(b => b.Inc(p => p.RepliesCount, -1)).ExecuteAsync(token);
 		}
 	}
 }

PrivaPub/Federation/Inbox/Handlers/UpdateHandler.cs

@@ -18,7 +18,6 @@ namespace PrivaPub.Federation.Inbox.Handlers
 {
 	public class UpdateHandler : IActivityHandler
 	{
-		const int MaxRevisions = 20;
 
 		readonly DbEntities _dbEntities;
 		readonly ILocalActorService _localActors;
@@ -70,69 +69,10 @@ namespace PrivaPub.Federation.Inbox.Handlers
 			}
 			Arrival.About(note.Type, post.Visibility, post.CreationDate);
 
-			post.Poll = note.Poll ?? post.Poll;
-			post.QuotePolicy = note.QuotePolicy;
-			post.Video = note.Video ?? post.Video;
-			post.Audio = note.Audio ?? post.Audio;
-			post.Event = note.Event ?? post.Event;
-			if (!IsEdit(note, post))
-			{
-				Arrival.Accept("refresh");
-				await DB.Default.SaveAsync(post, token);
-				await _records.Revise(note, Id(activity), token);
-				await Requote(post, note, token);
-				return;
-			}
-
-			Arrival.Accept("edit");
-			post.Revisions.Add(new PostRevision
-			{
-				Title = post.Title,
-				SpoilerText = post.SpoilerText,
-				ContentHtml = post.ContentHtml,
-				HasContentWarning = post.HasContentWarning,
-				EditedAt = post.EditedAt ?? post.CreationDate
-			});
-			if (post.Revisions.Count > MaxRevisions)
-				post.Revisions.RemoveRange(0, post.Revisions.Count - MaxRevisions);
-
-			var mentions = new List<PostMention>();
-			foreach (var mention in note.Mentions)
-			{
-				var local = await _localActors.FindByUri(mention.ActorURI, token);
-				mentions.Add(new PostMention { ActorURI = mention.ActorURI, Handle = mention.Handle, IsLocal = local != default, AccountId = local?.Id });
-			}
-
-			post.Title = note.Title;
-			post.SpoilerText = note.SpoilerText;
-			post.Excerpt = note.Excerpt;
-			post.Source = note.Source;
-			post.Emojis = note.Emojis.ToList();
-			post.CoverURL = note.CoverURL;
-			post.Link = note.Link;
-			post.HasContentWarning = note.Sensitive;
-			post.Text = note.ContentHtml;
-			post.ContentHtml = note.ContentHtml;
-			post.Language = note.Language;
-			post.Tags = note.Tags.ToList();
-			post.Mentions = mentions;
-			post.Media = note.Attachments.ToList();
-			post.EditedAt = note.Updated ?? DateTime.UtcNow;
-			post.UpdateDate = DateTime.UtcNow;
-			await DB.Default.SaveAsync(post, token);
-			await _records.Revise(note, Id(activity), token);
-			await Requote(post, note, token);
-			if (!string.IsNullOrEmpty(post.GroupId) && await _localActors.FindById(Models.Federation.LocalActorKind.Group, post.GroupId, token) is { IsCircle: false } community)
+			var edited = await RemoteEdits.Apply(post, note, Id(activity), _localActors, _records, _quotes, token);
+			Arrival.Accept(edited ? "edit" : "refresh");
+			if (edited && !string.IsNullOrEmpty(post.GroupId) && await _localActors.FindById(Models.Federation.LocalActorKind.Group, post.GroupId, token) is { IsCircle: false } community)
 				await _groups.Announce(community, activity.AsObject(), post.ObjectURI, isNewPost: false, token);
 		}
-
-		static bool IsEdit(NoteDocument note, PostEntity post) =>
-			note.Updated is { } updated && updated > (post.EditedAt ?? post.CreationDate);
-
-		async Task Requote(PostEntity post, NoteDocument note, CancellationToken token)
-		{
-			if (note.QuoteUri != post.QuoteURI || note.QuoteAuthorization != post.QuoteAuthorizationURI || post.QuoteState != QuoteState.Accepted)
-				await _quotes.Resolve(post, note, token);
-		}
 	}
 }

PrivaPub/Federation/Inbox/RemoteEdits.cs

@@ -0,0 +1,106 @@
+using MongoDB.Entities;
+
+using PrivaPub.Domain.Statuses;
+using PrivaPub.Federation.Actors;
+using PrivaPub.Federation.Objects;
+using PrivaPub.Models.Federation;
+using PrivaPub.Models.Post;
+using PrivaPub.Models.Social;
+
+using PostEntity = PrivaPub.Models.Post.Post;
+
+namespace PrivaPub.Federation.Inbox
+{
+	public static class RemoteEdits
+	{
+		public const int MaxRevisions = 20;
+
+		public static bool IsEdit(NoteDocument note, PostEntity post) =>
+			note.Updated is { } updated && updated > (post.EditedAt ?? post.CreationDate);
+
+		public static async Task<bool> Apply(PostEntity post, NoteDocument note, string activityId, ILocalActorService localActors, IObjectRecords records,
+			IQuoteService quotes, CancellationToken token)
+		{
+			post.Poll = note.Poll ?? post.Poll;
+			post.QuotePolicy = note.QuotePolicy;
+			post.Video = note.Video ?? post.Video;
+			post.Audio = note.Audio ?? post.Audio;
+			post.Event = note.Event ?? post.Event;
+			if (!IsEdit(note, post))
+			{
+				await DB.Default.SaveAsync(post, token);
+				await records.Revise(note, activityId, token);
+				await Requote(post, note, quotes, token);
+				return false;
+			}
+
+			post.Revisions.Add(new PostRevision
+			{
+				Title = post.Title,
+				SpoilerText = post.SpoilerText,
+				ContentHtml = post.ContentHtml,
+				HasContentWarning = post.HasContentWarning,
+				EditedAt = post.EditedAt ?? post.CreationDate
+			});
+			if (post.Revisions.Count > MaxRevisions)
+				post.Revisions.RemoveRange(0, post.Revisions.Count - MaxRevisions);
+
+			var mentions = new List<PostMention>();
+			foreach (var mention in note.Mentions)
+			{
+				var local = await localActors.FindByUri(mention.ActorURI, token);
+				mentions.Add(new PostMention { ActorURI = mention.ActorURI, Handle = mention.Handle, IsLocal = local != default, AccountId = local?.Id });
+			}
+
+			post.Title = note.Title;
+			post.SpoilerText = note.SpoilerText;
+			post.Excerpt = note.Excerpt;
+			post.Source = note.Source;
+			post.Emojis = note.Emojis.ToList();
+			post.CoverURL = note.CoverURL;
+			post.Link = note.Link;
+			post.HasContentWarning = note.Sensitive;
+			post.Text = note.ContentHtml;
+			post.ContentHtml = note.ContentHtml;
+			post.Language = note.Language;
+			post.Tags = note.Tags.ToList();
+			post.Mentions = mentions;
+			post.Media = note.Attachments.ToList();
+			post.EditedAt = note.Updated ?? DateTime.UtcNow;
+			post.UpdateDate = DateTime.UtcNow;
+			await DB.Default.SaveAsync(post, token);
+			await records.Revise(note, activityId, token);
+			await Requote(post, note, quotes, token);
+			return true;
+		}
+
+		static async Task Requote(PostEntity post, NoteDocument note, IQuoteService quotes, CancellationToken token)
+		{
+			if (note.QuoteUri != post.QuoteURI || note.QuoteAuthorization != post.QuoteAuthorizationURI || post.QuoteState != QuoteState.Accepted)
+				await quotes.Resolve(post, note, token);
+		}
+	}
+
+	public static class RemoteDeletes
+	{
+		public static async Task Tombstone(string objectUri, CancellationToken token) =>
+			await DB.Default.Update<DeletedObject>()
+				.Match(d => d.ObjectURI == objectUri)
+				.Modify(d => d.DeletedAt, DateTime.UtcNow)
+				.Option(o => o.IsUpsert = true)
+				.ExecuteAsync(token);
+
+		public static async Task Remove(PostEntity post, string objectUri, CancellationToken token)
+		{
+			await Tombstone(objectUri, token);
+			await DB.Default.DeleteAsync<PostEntity>(post.ID);
+			await DB.Default.DeleteAsync<ObjectRecord>(r => r.PostId == post.ID || r.ObjectURI == objectUri);
+			await DB.Default.DeleteAsync<TimelineEntry>(e => e.PostId == post.ID || e.ReblogOfPostId == post.ID);
+			await DB.Default.DeleteAsync<PostEntity>(p => p.ReblogOfPostId == post.ID);
+			if (!string.IsNullOrEmpty(post.AnsweringToPostId))
+				await DB.Default.Update<PostEntity>().MatchID(post.AnsweringToPostId).Modify(b => b.Inc(p => p.RepliesCount, -1)).ExecuteAsync(token);
+			if (post.QuoteState == QuoteState.Accepted && !string.IsNullOrEmpty(post.QuotedPostId))
+				await DB.Default.Update<PostEntity>().MatchID(post.QuotedPostId).Modify(b => b.Inc(p => p.QuotesCount, -1)).ExecuteAsync(token);
+		}
+	}
+}

PrivaPub/Federation/Objects/ObjectRecords.cs

@@ -34,8 +34,10 @@ namespace PrivaPub.Federation.Objects
 		public async Task Record(NoteDocument note, PostEntity post, ObjectPath path, bool refetched, CancellationToken token)
 		{
 			var arrival = Arrival.Current;
+			var delivered = path == ObjectPath.Delivered;
 			var raw = Capture(note.Raw);
 			var host = new Uri(note.Id).Host.ToLowerInvariant();
+			var activityContext = !delivered || note.Raw?.ContainsKey("@context") == true || arrival?.Context?.Length > 16 * 1024 ? default : arrival?.Context;
 			var record = new ObjectRecord
 			{
 				ObjectURI = note.Id,
@@ -46,20 +48,22 @@ namespace PrivaPub.Federation.Objects
 				RawHash = raw.Hash,
 				RawBytes = raw.Bytes,
 				RawTruncated = raw.Truncated,
-				ActivityContext = note.Raw?.ContainsKey("@context") == true || arrival?.Context?.Length > 16 * 1024 ? default : arrival?.Context,
+				ActivityContext = activityContext,
 				Path = path,
 				Refetched = refetched,
 				ActivityId = arrival?.ActivityId,
 				ActivityType = arrival?.ActivityType,
 				ActivityActorURI = arrival?.ActorURI,
-				Inbox = path == ObjectPath.Delivered ? arrival?.Inbox : default,
-				SignatureScheme = arrival?.KeyId == default ? default : "draft-cavage",
-				KeyId = arrival?.KeyId,
-				Algorithm = arrival?.Algorithm,
-				SignedHeaders = arrival?.SignedHeaders?.ToList() ?? new(),
-				ReceivedAt = arrival?.ReceivedAt ?? DateTime.UtcNow,
+				Inbox = delivered ? arrival?.Inbox : default,
+				SignatureScheme = !delivered || arrival?.KeyId == default ? default : "draft-cavage",
+				KeyId = delivered ? arrival?.KeyId : default,
+				Algorithm = delivered ? arrival?.Algorithm : default,
+				SignedHeaders = delivered ? arrival?.SignedHeaders?.ToList() ?? new() : new(),
+				ReceivedAt = delivered ? arrival?.ReceivedAt ?? DateTime.UtcNow : DateTime.UtcNow,
 				Published = note.Published,
-				Updated = note.Updated
+				Updated = note.Updated,
+				Extensions = ObjectFeatures.Detect(note.Raw),
+				ContextNamespaces = ObjectFeatures.Namespaces(note.Raw, activityContext)
 			};
 			try
 			{