Outbound documents speak Mastodon's dialect under PrivaPub's route names

Local text (Domain/Content/ContentRenderer): Markdig with raw HTML off and
autolinks, or plain text for API clients; then @user and @user@host are
resolved (locally or through WebFinger) into Mastodon's h-card markup and
#tags into hashtag links, skipping code, links and e-mail addresses. A
post stores the result, its mentions and its tags, and is delivered to
the mentioned actors and the parent's author as well as to followers.

Renderer:
- Mastodon's @context (toot, schema PropertyValue, discoverable,
  indexable, blurhash, focalPoint, featured, alsoKnownAs, movedTo) and
  FEP-2c59's webfinger;
- an actor's url is its HTML page, its fields are PropertyValue
  attachments, published is cut to the day and indexable is false;
- a note's content is the stored rendering; a title becomes name and a
  bold first line, a content warning without its own text is summarised
  by the title or "Content warning"; Mention and Hashtag tags, contentMap,
  updated, and to/cc by visibility.

Routes take the agreed names: /groupies, /stalking, /scribbles/{id},
/grunts/{id} (a Create resolves), /whispers/{id} for a DM's context. The
outbox is a collection with a first page, paged by max_id. A browser
asking for an actor or a note is redirected to /@user, and WebFinger's
profile-page points there.

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

PrivaPub/Federation/Actors/LocalActorService.cs

@@ -31,18 +31,22 @@ namespace PrivaPub.Federation.Actors
 		public bool IsFederated { get; init; } = true;
 		public DateTime Published { get; init; }
 		public string BaseAddress { get; init; }
+		public IReadOnlyDictionary<string, string> Fields { get; init; } = new Dictionary<string, string>();
 
 		public string Uri => $"{BaseAddress}/peasants/{UserName}";
 		public string KeyId => $"{Uri}#main-key";
 		public string Inbox => $"{Uri}/mouth";
 		public string Outbox => $"{Uri}/anus";
-		public string Followers => $"{Uri}/followers";
-		public string Following => $"{Uri}/following";
+		public string Followers => $"{Uri}/groupies";
+		public string Following => $"{Uri}/stalking";
 		public string SharedInbox => $"{BaseAddress}/human-centipede";
 		public string Domain => new Uri(BaseAddress).Authority;
 		public string Handle => $"{UserName}@{Domain}";
-		public string PostUri(string postId) => $"{Uri}/posts/{postId}";
-		public string ActivityUri(string activityId) => $"{Uri}/activities/{activityId}";
+		public string HtmlUrl => $"{BaseAddress}/@{UserName}";
+		public string PostUri(string postId) => $"{Uri}/scribbles/{postId}";
+		public string PostHtmlUrl(string postId) => $"{HtmlUrl}/{postId}";
+		public string ActivityUri(string activityId) => $"{Uri}/grunts/{activityId}";
+		public string ConversationUri(string conversationId) => $"{Uri}/whispers/{conversationId}";
 	}
 
 	public interface ILocalActorService
@@ -190,6 +194,7 @@ namespace PrivaPub.Federation.Actors
 			PrivateKeyPem = avatar.PrivateKey,
 			PublicKeyPem = avatar.PublicKey,
 			Published = avatar.CreatedAt,
+			Fields = avatar.Fields ?? new Dictionary<string, string>(),
 			BaseAddress = BaseAddress
 		};
 

PrivaPub/Federation/Controllers/PeasantsController.cs

@@ -41,26 +41,39 @@ namespace PrivaPub.Federation.Controllers
 		public async Task<IActionResult> GetActor(string actor, CancellationToken token)
 		{
 			var local = await _localActors.FindByUserName(actor, token);
-			return local is not { IsFederated: true } ? NotFound() : Activity(ActivityPubRenderer.Actor(local));
+			if (local is not { IsFederated: true })
+				return NotFound();
+			if (WantsHtml() && local.Kind != LocalActorKind.Application)
+				return Redirect(local.HtmlUrl);
+			return Activity(ActivityPubRenderer.Actor(local));
 		}
 
 		[HttpGet, Route("{actor}/anus")]
-		public async Task<IActionResult> Outbox(string actor, CancellationToken token)
+		public async Task<IActionResult> Outbox(string actor, [FromQuery] bool page, [FromQuery(Name = "max_id")] string maxId,
+			CancellationToken token)
 		{
 			var local = await _localActors.FindByUserName(actor, token);
 			if (local is not { IsFederated: true })
 				return NotFound();
 
-			var total = local.Kind == LocalActorKind.Group
-				? await DB.Default.CountAsync<PostEntity>(p => p.GroupId == local.Id && (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted), token)
-				: await DB.Default.CountAsync<PostEntity>(p => p.GroupUserId == local.Id && !p.IsFederatedCopy && (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted), token);
+			if (!page)
+			{
+				var total = local.Kind == LocalActorKind.Group
+					? await DB.Default.CountAsync<PostEntity>(p => p.GroupId == local.Id && !p.DeletedAt.HasValue
+						&& (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted), token)
+					: await DB.Default.CountAsync<PostEntity>(p => p.GroupUserId == local.Id && !p.IsFederatedCopy && !p.DeletedAt.HasValue
+						&& (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted), token);
+				return Activity(ActivityPubRenderer.OrderedCollection(local.Outbox, (int)total, default, $"{local.Outbox}?page=true"));
+			}
 
-			var latest = await (local.Kind == LocalActorKind.Group
-					? _dbEntities.Posts.Match(p => p.GroupId == local.Id && (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted))
-					: _dbEntities.Posts.Match(p => p.GroupUserId == local.Id && !p.IsFederatedCopy && (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted)))
-				.Sort(p => p.CreationDate, Order.Descending)
-				.Limit(OutboxSize)
-				.ExecuteAsync(token);
+			var query = local.Kind == LocalActorKind.Group
+				? _dbEntities.Posts.Match(p => p.GroupId == local.Id && !p.DeletedAt.HasValue
+					&& (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted))
+				: _dbEntities.Posts.Match(p => p.GroupUserId == local.Id && !p.IsFederatedCopy && !p.DeletedAt.HasValue
+					&& (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted));
+			if (!string.IsNullOrEmpty(maxId))
+				query.Match(f => f.Lt(p => p.ID, maxId));
+			var latest = await query.Sort(p => p.ID, Order.Descending).Limit(OutboxSize).ExecuteAsync(token);
 
 			var items = new List<JsonNode>();
 			foreach (var post in latest)
@@ -70,15 +83,15 @@ namespace PrivaPub.Federation.Controllers
 					items.Add(ActivityPubRenderer.Announce(local, post.ObjectURI, $"announce-{post.ID}"));
 					continue;
 				}
-				var group = string.IsNullOrEmpty(post.GroupId) ? default : await _localActors.FindById(LocalActorKind.Group, post.GroupId, token);
-				var note = ActivityPubRenderer.Note(post, local, group, post.InReplyToURI);
-				items.Add(ActivityPubRenderer.Create(local, note, $"create-{post.ID}"));
+				items.Add(await CreateFor(post, local, token));
 			}
 
-			return Activity(ActivityPubRenderer.OrderedCollection(local.Outbox, (int)total, items));
+			var pageId = string.IsNullOrEmpty(maxId) ? $"{local.Outbox}?page=true" : $"{local.Outbox}?page=true&max_id={maxId}";
+			var next = latest.Count == OutboxSize ? $"{local.Outbox}?page=true&max_id={latest[^1].ID}" : default;
+			return Activity(ActivityPubRenderer.OrderedCollectionPage(pageId, local.Outbox, items, next, default));
 		}
 
-		[HttpGet, Route("{actor}/followers")]
+		[HttpGet, Route("{actor}/groupies")]
 		public async Task<IActionResult> Followers(string actor, CancellationToken token)
 		{
 			var local = await _localActors.FindByUserName(actor, token);
@@ -89,32 +102,37 @@ namespace PrivaPub.Federation.Controllers
 			return Activity(ActivityPubRenderer.OrderedCollection(local.Followers, (int)count, default));
 		}
 
-		[HttpGet, Route("{actor}/following")]
+		[HttpGet, Route("{actor}/stalking")]
 		public async Task<IActionResult> Following(string actor, CancellationToken token)
 		{
 			var local = await _localActors.FindByUserName(actor, token);
-			return local is not { IsFederated: true } ? NotFound() : Activity(ActivityPubRenderer.OrderedCollection(local.Following, 0, Enumerable.Empty<JsonNode>()));
+			return local is not { IsFederated: true } ? NotFound() : Activity(ActivityPubRenderer.OrderedCollection(local.Following, 0, default));
 		}
 
-		[HttpGet, Route("{actor}/posts/{postId}")]
+		[HttpGet, Route("{actor}/scribbles/{postId}")]
 		public async Task<IActionResult> Post(string actor, string postId, CancellationToken token)
 		{
-			var local = await _localActors.FindByUserName(actor, token);
-			if (local == default || local.Kind != LocalActorKind.Person)
-				return NotFound();
-
-			var post = await _dbEntities.Posts
-				.Match(p => p.ID == postId && p.GroupUserId == local.Id && !p.IsFederatedCopy && (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted))
-				.ExecuteFirstAsync(token);
+			var (local, post) = await PublicPost(actor, postId, token);
 			if (post == default)
 				return NotFound();
+			if (WantsHtml())
+				return Redirect(local.PostHtmlUrl(post.ID));
 
 			var group = string.IsNullOrEmpty(post.GroupId) ? default : await _localActors.FindById(LocalActorKind.Group, post.GroupId, token);
 			var note = ActivityPubRenderer.Note(post, local, group, post.InReplyToURI);
-			note["@context"] = ActivityPubRenderer.ActivityStreams;
+			note["@context"] = ActivityPubRenderer.Context();
 			return Activity(note);
 		}
 
+		[HttpGet, Route("{actor}/grunts/{activityId}")]
+		public async Task<IActionResult> Grunt(string actor, string activityId, CancellationToken token)
+		{
+			if (!activityId.StartsWith("create-", StringComparison.Ordinal))
+				return NotFound();
+			var (local, post) = await PublicPost(actor, activityId["create-".Length..], token);
+			return post == default ? NotFound() : Activity(await CreateFor(post, local, token));
+		}
+
 		[HttpPost, Route("{actor}/mouth"), EnableRateLimiting(RateLimiting.Inbox)]
 		public async Task<IActionResult> Inbox(string actor, CancellationToken token)
 		{
@@ -132,6 +150,33 @@ namespace PrivaPub.Federation.Controllers
 		public async Task<IActionResult> SharedInbox(CancellationToken token) =>
 			Answer(await _inbox.Receive(Request, default, token));
 
+		async Task<(LocalActor Actor, PostEntity Post)> PublicPost(string actor, string postId, CancellationToken token)
+		{
+			var local = await _localActors.FindByUserName(actor, token);
+			if (local is not { IsFederated: true, Kind: LocalActorKind.Person })
+				return default;
+			var post = await _dbEntities.Posts
+				.Match(p => p.ID == postId && p.GroupUserId == local.Id && !p.IsFederatedCopy && !p.DeletedAt.HasValue
+					&& (p.Visibility == PostVisibility.Public || p.Visibility == PostVisibility.Unlisted))
+				.ExecuteFirstAsync(token);
+			return (local, post);
+		}
+
+		async Task<JsonObject> CreateFor(PostEntity post, LocalActor author, CancellationToken token)
+		{
+			var group = string.IsNullOrEmpty(post.GroupId) ? default : await _localActors.FindById(LocalActorKind.Group, post.GroupId, token);
+			var note = ActivityPubRenderer.Note(post, author, group, post.InReplyToURI);
+			return ActivityPubRenderer.Create(author, note, $"create-{post.ID}");
+		}
+
+		bool WantsHtml()
+		{
+			var accept = Request.Headers.Accept.ToString();
+			return accept.Contains("text/html", StringComparison.OrdinalIgnoreCase)
+				&& !accept.Contains("activity+json", StringComparison.OrdinalIgnoreCase)
+				&& !accept.Contains("ld+json", StringComparison.OrdinalIgnoreCase);
+		}
+
 		IActionResult Answer(InboxResult result)
 		{
 			if (result.Error != default)

PrivaPub/Federation/Controllers/WellKnownController.cs

@@ -49,10 +49,12 @@ namespace PrivaPub.Federation.Controllers
 			var document = new JsonObject
 			{
 				["subject"] = $"acct:{actor.Handle}",
-				["aliases"] = new JsonArray(actor.Uri),
-				["links"] = new JsonArray(
-					new JsonObject { ["rel"] = "self", ["type"] = "application/activity+json", ["href"] = actor.Uri },
-					new JsonObject { ["rel"] = "http://webfinger.net/rel/profile-page", ["type"] = "text/html", ["href"] = actor.Uri })
+				["aliases"] = actor.Kind == LocalActorKind.Application ? new JsonArray(actor.Uri) : new JsonArray(actor.HtmlUrl, actor.Uri),
+				["links"] = actor.Kind == LocalActorKind.Application
+					? new JsonArray(new JsonObject { ["rel"] = "self", ["type"] = "application/activity+json", ["href"] = actor.Uri })
+					: new JsonArray(
+						new JsonObject { ["rel"] = "http://webfinger.net/rel/profile-page", ["type"] = "text/html", ["href"] = actor.HtmlUrl },
+						new JsonObject { ["rel"] = "self", ["type"] = "application/activity+json", ["href"] = actor.Uri })
 			};
 			return Content(document.ToJsonString(), "application/jrd+json; charset=utf-8");
 		}

PrivaPub/Federation/Rendering/ActivityPubRenderer.cs

@@ -1,33 +1,65 @@
 using Markdig;
 
+using PrivaPub.Federation.Actors;
+using PrivaPub.Federation.Objects;
 using PrivaPub.Models.Federation;
+using PrivaPub.Models.Post;
 
 using System.Globalization;
+using System.Net;
 using System.Text.Json.Nodes;
 
 using PostEntity = PrivaPub.Models.Post.Post;
-using PrivaPub.Federation.Actors;
 
 namespace PrivaPub.Federation.Rendering
 {
 	public static class ActivityPubRenderer
 	{
 		public const string ActivityStreams = "https://www.w3.org/ns/activitystreams";
-		public const string Public = "https://www.w3.org/ns/activitystreams#Public";
+		public const string Public = Addressing.Public;
+		public const string ContentWarning = "Content warning";
 
 		static readonly MarkdownPipeline Pipeline = new MarkdownPipelineBuilder().DisableHtml().Build();
 
+		public static JsonArray Context() => new(
+			ActivityStreams,
+			"https://w3id.org/security/v1",
+			new JsonObject
+			{
+				["manuallyApprovesFollowers"] = "as:manuallyApprovesFollowers",
+				["sensitive"] = "as:sensitive",
+				["Hashtag"] = "as:Hashtag",
+				["alsoKnownAs"] = new JsonObject { ["@id"] = "as:alsoKnownAs", ["@type"] = "@id" },
+				["movedTo"] = new JsonObject { ["@id"] = "as:movedTo", ["@type"] = "@id" },
+				["toot"] = "http://joinmastodon.org/ns#",
+				["featured"] = new JsonObject { ["@id"] = "toot:featured", ["@type"] = "@id" },
+				["featuredTags"] = new JsonObject { ["@id"] = "toot:featuredTags", ["@type"] = "@id" },
+				["discoverable"] = "toot:discoverable",
+				["indexable"] = "toot:indexable",
+				["blurhash"] = "toot:blurhash",
+				["focalPoint"] = new JsonObject { ["@container"] = "@list", ["@id"] = "toot:focalPoint" },
+				["schema"] = "http://schema.org#",
+				["PropertyValue"] = "schema:PropertyValue",
+				["value"] = "schema:value",
+				["webfinger"] = "https://purl.archive.org/socialweb/webfinger#webfinger"
+			});
+
 		public static string Html(string markdown) =>
 			string.IsNullOrEmpty(markdown) ? string.Empty : Markdown.ToHtml(markdown, Pipeline).Trim();
 
 		public static string Timestamp(DateTime value) =>
 			DateTime.SpecifyKind(value, DateTimeKind.Utc).ToString("yyyy-MM-ddTHH:mm:ssZ", CultureInfo.InvariantCulture);
 
+		public static string Day(DateTime value) =>
+			DateTime.SpecifyKind(value, DateTimeKind.Utc).Date.ToString("yyyy-MM-ddT00:00:00Z", CultureInfo.InvariantCulture);
+
+		public static string TagUrl(string baseAddress, string tag) => $"{baseAddress}/tags/{Uri.EscapeDataString(tag)}";
+
 		public static JsonObject Actor(LocalActor actor)
 		{
 			var document = new JsonObject
 			{
-				["@context"] = new JsonArray(ActivityStreams, "https://w3id.org/security/v1"),
+				["@context"] = Context(),
 				["id"] = actor.Uri,
 				["type"] = actor.Kind switch
 				{
@@ -38,21 +70,29 @@ namespace PrivaPub.Federation.Rendering
 				["preferredUsername"] = actor.UserName,
 				["name"] = actor.Name,
 				["summary"] = Html(actor.Summary),
-				["url"] = actor.Uri,
+				["url"] = actor.Kind == LocalActorKind.Application ? actor.Uri : actor.HtmlUrl,
 				["inbox"] = actor.Inbox,
 				["outbox"] = actor.Outbox,
 				["followers"] = actor.Followers,
 				["following"] = actor.Following,
-				["published"] = Timestamp(actor.Published),
+				["published"] = Day(actor.Published),
 				["manuallyApprovesFollowers"] = actor.ManuallyApprovesFollowers,
 				["discoverable"] = actor.Discoverable,
+				["indexable"] = false,
+				["webfinger"] = actor.Handle,
 				["endpoints"] = new JsonObject { ["sharedInbox"] = actor.SharedInbox },
 				["publicKey"] = new JsonObject
 				{
 					["id"] = actor.KeyId,
 					["owner"] = actor.Uri,
 					["publicKeyPem"] = Keys.ToSubjectPublicKeyInfoPem(actor.PublicKeyPem)
-				}
+				},
+				["attachment"] = new JsonArray(actor.Fields.Select(field => (JsonNode)new JsonObject
+				{
+					["type"] = "PropertyValue",
+					["name"] = field.Key,
+					["value"] = FieldValue(field.Value)
+				}).ToArray())
 			};
 			if (!string.IsNullOrEmpty(actor.PictureURL))
 				document["icon"] = new JsonObject { ["type"] = "Image", ["url"] = actor.PictureURL };
@@ -63,13 +103,18 @@ namespace PrivaPub.Federation.Rendering
 
 		public static JsonObject Note(PostEntity post, LocalActor author, LocalActor group, string inReplyTo)
 		{
-			var to = new JsonArray(Public);
-			var cc = new JsonArray(author.Followers);
+			var mentions = post.Mentions.Select(m => (JsonNode)m.ActorURI).ToArray();
+			var (to, cc) = post.Visibility switch
+			{
+				PostVisibility.Unlisted => (new JsonArray(author.Followers), new JsonArray(mentions.Prepend(Public).ToArray())),
+				PostVisibility.FollowersOnly => (new JsonArray(author.Followers), new JsonArray(mentions)),
+				PostVisibility.Direct => (new JsonArray(mentions), new JsonArray()),
+				_ => (new JsonArray(Public), new JsonArray(mentions.Prepend(author.Followers).ToArray()))
+			};
 			if (group != default)
 				cc.Add(group.Uri);
 
-			var note = NoteBody(author.PostUri(post.ID), author, post.Title, post.Text, post.HasContentWarning,
-				post.CreationDate, to, cc, inReplyTo);
+			var note = NoteBody(post, author, to, cc, inReplyTo);
 			if (group != default)
 				note["audience"] = group.Uri;
 			return note;
@@ -78,48 +123,84 @@ namespace PrivaPub.Federation.Rendering
 		public static JsonObject DirectNote(PostEntity post, LocalActor author, IReadOnlyList<(string Uri, string Handle)> recipients,
 			string context)
 		{
-			var note = NoteBody(author.PostUri(post.ID), author, post.Title, post.Text, post.HasContentWarning,
-				post.CreationDate, new JsonArray(recipients.Select(r => (JsonNode)r.Uri).ToArray()), new JsonArray(), default);
-			note["tag"] = new JsonArray(recipients.Select(r => (JsonNode)new JsonObject
-			{
-				["type"] = "Mention",
-				["href"] = r.Uri,
-				["name"] = "@" + r.Handle
-			}).ToArray());
-			note["content"] = string.Join(" ", recipients.Select(r => $"<span class=\"h-card\"><a href=\"{r.Uri}\" class=\"u-url mention\">@{r.Handle}</a></span>"))
-				+ " " + note["content"]!.GetValue<string>();
+			var note = NoteBody(post, author, new JsonArray(recipients.Select(r => (JsonNode)r.Uri).ToArray()), new JsonArray(), post.InReplyToURI);
+			var named = post.Mentions.Select(m => m.ActorURI).ToHashSet();
+			var tags = note["tag"]!.AsArray();
+			foreach (var recipient in recipients.Where(r => !named.Contains(r.Uri)))
+				tags.Add(new JsonObject { ["type"] = "Mention", ["href"] = recipient.Uri, ["name"] = "@" + recipient.Handle });
+			var unmentioned = recipients.Where(r => !named.Contains(r.Uri)).ToList();
+			if (unmentioned.Count > 0)
+				note["content"] = "<p>" + string.Join(" ", unmentioned.Select(r =>
+						$"<span class=\"h-card\" translate=\"no\"><a href=\"{WebUtility.HtmlEncode(r.Uri)}\" class=\"u-url mention\">@<span>{WebUtility.HtmlEncode(r.Handle.Split('@')[0])}</span></a></span>"))
+					+ "</p>" + note["content"]!.GetValue<string>();
 			if (!string.IsNullOrEmpty(context))
 				note["context"] = context;
 			return note;
 		}
 
-		static JsonObject NoteBody(string id, LocalActor author, string title, string text, bool sensitive,
-			DateTime published, JsonArray to, JsonArray cc, string inReplyTo)
+		static JsonObject NoteBody(PostEntity post, LocalActor author, JsonArray to, JsonArray cc, string inReplyTo)
 		{
+			var content = post.ContentHtml ?? Html(post.Text);
+			if (!string.IsNullOrEmpty(post.Title))
+				content = $"<p><strong>{WebUtility.HtmlEncode(post.Title)}</strong></p>{content}";
+
 			var note = new JsonObject
 			{
-				["id"] = id,
+				["id"] = author.PostUri(post.ID),
 				["type"] = "Note",
 				["attributedTo"] = author.Uri,
-				["content"] = Html(text),
-				["published"] = Timestamp(published),
-				["url"] = id,
+				["content"] = content,
+				["published"] = Timestamp(post.CreationDate),
+				["url"] = author.PostHtmlUrl(post.ID),
 				["to"] = to,
 				["cc"] = cc,
-				["sensitive"] = sensitive
+				["sensitive"] = post.HasContentWarning,
+				["tag"] = new JsonArray(post.Mentions
+					.Select(m => (JsonNode)new JsonObject { ["type"] = "Mention", ["href"] = m.ActorURI, ["name"] = MentionName(m) })
+					.Concat(post.Tags.Select(t => (JsonNode)new JsonObject
+					{
+						["type"] = "Hashtag",
+						["href"] = TagUrl(author.BaseAddress, t),
+						["name"] = "#" + t
+					}))
+					.ToArray())
 			};
-			if (sensitive && !string.IsNullOrEmpty(title))
-				note["summary"] = title;
-			else if (!string.IsNullOrEmpty(title))
-				note["name"] = title;
+			if (!string.IsNullOrEmpty(post.Language))
+				note["contentMap"] = new JsonObject { [post.Language] = content };
+			if (!string.IsNullOrEmpty(post.Title))
+				note["name"] = post.Title;
+			var summary = post.SpoilerText ?? (post.HasContentWarning ? post.Title ?? ContentWarning : default);
+			if (!string.IsNullOrEmpty(summary))
+			{
+				note["summary"] = summary;
+				note["sensitive"] = true;
+			}
 			if (!string.IsNullOrEmpty(inReplyTo))
 				note["inReplyTo"] = inReplyTo;
+			if (post.EditedAt.HasValue)
+				note["updated"] = Timestamp(post.EditedAt.Value);
 			return note;
 		}
 
+		static string MentionName(PostMention mention)
+		{
+			var handle = mention.Handle?.TrimStart('@');
+			if (string.IsNullOrEmpty(handle))
+				return "@" + mention.ActorURI;
+			return "@" + (handle.Contains('@') ? handle : $"{handle}@{new Uri(mention.ActorURI).Authority}");
+		}
+
+		static string FieldValue(string value)
+		{
+			var encoded = WebUtility.HtmlEncode(value ?? string.Empty);
+			return Uri.TryCreate(value, UriKind.Absolute, out var link) && link.Scheme is "https" or "http"
+				? $"<a href=\"{encoded}\" target=\"_blank\" rel=\"nofollow noopener noreferrer me\" translate=\"no\">{encoded}</a>"
+				: encoded;
+		}
+
 		public static JsonObject Create(LocalActor actor, JsonObject note, string activityId) => new()
 		{
-			["@context"] = ActivityStreams,
+			["@context"] = Context(),
 			["id"] = actor.ActivityUri(activityId),
 			["type"] = "Create",
 			["actor"] = actor.Uri,
@@ -161,7 +242,7 @@ namespace PrivaPub.Federation.Rendering
 			["object"] = follow.DeepClone()
 		};
 
-		public static JsonObject OrderedCollection(string id, int totalItems, IEnumerable<JsonNode> items)
+		public static JsonObject OrderedCollection(string id, int totalItems, IEnumerable<JsonNode> items, string first = default)
 		{
 			var collection = new JsonObject
 			{
@@ -170,9 +251,28 @@ namespace PrivaPub.Federation.Rendering
 				["type"] = "OrderedCollection",
 				["totalItems"] = totalItems
 			};
+			if (first != default)
+				collection["first"] = first;
 			if (items != default)
 				collection["orderedItems"] = new JsonArray(items.ToArray());
 			return collection;
 		}
+
+		public static JsonObject OrderedCollectionPage(string id, string partOf, IEnumerable<JsonNode> items, string next, string prev)
+		{
+			var page = new JsonObject
+			{
+				["@context"] = Context(),
+				["id"] = id,
+				["type"] = "OrderedCollectionPage",
+				["partOf"] = partOf,
+				["orderedItems"] = new JsonArray(items.ToArray())
+			};
+			if (next != default)
+				page["next"] = next;
+			if (prev != default)
+				page["prev"] = prev;
+			return page;
+		}
 	}
 }