[backend/federation] Improve hashtag handling (ISH-651)

Iceshrimp.Backend/Core/Helpers/LibMfm/Conversion/MfmConverter.cs

@@ -49,7 +49,9 @@ public class MfmConverter(
 	public AsyncLocal<bool> SupportsHtmlFormatting { get; } = new();
 	public AsyncLocal<bool> SupportsInlineMedia    { get; } = new();
 
-	public static async Task<HtmlMfmData> FromHtmlAsync(string? html, List<Note.MentionedUser>? mentions = null)
+	public static async Task<HtmlMfmData> FromHtmlAsync(
+		string? html, List<Note.MentionedUser>? mentions = null, List<string>? hashtags = null
+	)
 	{
 		var media = new List<MfmInlineMedia>();
 		if (html == null) return new HtmlMfmData("", media);
@@ -68,7 +70,7 @@ public class MfmConverter(
 		if (dom.Body == null) return new HtmlMfmData("", media);
 
 		var sb     = new StringBuilder();
-		var parser = new MfmHtmlParser(mentions ?? [], media);
+		var parser = new MfmHtmlParser(mentions ?? [], hashtags ?? [], media);
 		dom.Body.ChildNodes.Select(parser.ParseNode).ToList().ForEach(s => sb.Append(s));
 		return new HtmlMfmData(sb.ToString().Trim(), media);
 	}

Iceshrimp.Backend/Core/Helpers/LibMfm/Parsing/HtmlParser.cs

@@ -5,7 +5,11 @@ using Iceshrimp.Backend.Core.Helpers.LibMfm.Conversion;
 
 namespace Iceshrimp.Backend.Core.Helpers.LibMfm.Parsing;
 
-internal class HtmlParser(IEnumerable<Note.MentionedUser> mentions, ICollection<MfmInlineMedia> media)
+internal class HtmlParser(
+	IEnumerable<Note.MentionedUser> mentions,
+	IEnumerable<string> hashtags,
+	ICollection<MfmInlineMedia> media
+)
 {
 	internal string? ParseNode(INode node)
 	{
@@ -35,6 +39,14 @@ internal class HtmlParser(IEnumerable<Note.MentionedUser> mentions, ICollection<
 						: $"<plain>{el.TextContent}</plain>";
 				}
 
+				// Hubzilla marks tags as class="zrl", so we have to account for that here
+				if ((el.GetAttribute("rel") is "tag" || el.ClassList.Contains("zrl")) && el.HasAttribute("href"))
+				{
+					var text = el.TextContent;
+					if (hashtags.Contains((text.StartsWith('#') ? text[1..] : text).ToLowerInvariant()))
+						return text;
+				}
+
 				if (el.TextContent == href && (href.StartsWith("http://") || href.StartsWith("https://")))
 					return href;
 
@@ -87,7 +99,8 @@ internal class HtmlParser(IEnumerable<Note.MentionedUser> mentions, ICollection<
 				if (node is not HtmlElement el) return node.TextContent;
 
 				var src = el.GetAttribute("src");
-				if (src == null || !Uri.TryCreate(src, UriKind.Absolute, out var uri) && uri is { Scheme: "http" or "https" })
+				if (src == null
+				    || !Uri.TryCreate(src, UriKind.Absolute, out var uri) && uri is { Scheme: "http" or "https" })
 					return node.TextContent;
 
 				var alt = el.GetAttribute("alt") ?? el.GetAttribute("title");

Iceshrimp.Backend/Core/Services/NoteService.cs

@@ -201,16 +201,6 @@ public class NoteService(
 		}
 
 		var tags = ResolveHashtags(data.ParsedText, data.ASNote);
-		if (tags.Count > 0 && data.Text != null && data.ASNote != null)
-		{
-			// @formatter:off
-			var match = data.ASNote.Tags?.OfType<ASHashtag>().Where(p => p.Name != null && p.Href != null) ?? [];
-			//TODO: refactor this to use the nodes object instead of matching on text
-			data.Text = match.Aggregate(data.Text, (current, tag) => current.Replace($"[#{tag.Name!.TrimStart('#')}]({tag.Href})", $"#{tag.Name!.TrimStart('#')}")
-			                                                      .Replace($"#[{tag.Name!.TrimStart('#')}]({tag.Href})", $"#{tag.Name!.TrimStart('#')}"));
-			// @formatter:on
-		}
-
 		var mastoReplyUserId = data.Reply?.UserId != data.User.Id
 			? data.Reply?.UserId
 			: data.Reply.MastoReplyUserId ?? data.Reply.ReplyUserId ?? data.Reply.UserId;
@@ -1009,7 +999,13 @@ public class NoteService(
 
 		if (text == null)
 		{
-			(text, htmlInlineMedia) = await MfmConverter.FromHtmlAsync(note.Content, mentionData.Mentions);
+			var hashtags = note.Tags?.OfType<ASHashtag>()
+			                   .Select(p => p.Name?.ToLowerInvariant().TrimStart('#'))
+			                   .NotNull()
+			                   .ToList()
+			               ?? [];
+
+			(text, htmlInlineMedia) = await MfmConverter.FromHtmlAsync(note.Content, mentionData.Mentions, hashtags);
 		}
 
 		var cw  = note.Summary;
@@ -1099,7 +1095,15 @@ public class NoteService(
 		List<MfmInlineMedia>? htmlInlineMedia = null;
 
 		if (text == null)
-			(text, htmlInlineMedia) = await MfmConverter.FromHtmlAsync(note.Content, mentionData.Mentions);
+		{
+			var hashtags = note.Tags?.OfType<ASHashtag>()
+			                   .Select(p => p.Name?.ToLowerInvariant().TrimStart('#'))
+			                   .NotNull()
+			                   .ToList()
+			               ?? [];
+
+			(text, htmlInlineMedia) = await MfmConverter.FromHtmlAsync(note.Content, mentionData.Mentions, hashtags);
+		}
 
 		var cw = note.Summary;
 

Iceshrimp.Backend/Core/Services/UserService.cs

@@ -156,8 +156,18 @@ public class UserService(
 			             .AwaitAllAsync()
 			: null;
 
-		var bio = actor.MkSummary?.ReplaceLineEndings("\n").Trim()
+		var bio = actor.MkSummary?.ReplaceLineEndings("\n").Trim();
-		          ?? (await MfmConverter.FromHtmlAsync(actor.Summary)).Mfm;
+		if (bio == null)
+		{
+			var asHashtags = actor.Tags?.OfType<ASHashtag>()
+			                      .Select(p => p.Name?.ToLowerInvariant().TrimStart('#'))
+			                      .NotNull()
+			                      .ToList()
+			                 ?? [];
+
+			bio = (await MfmConverter.FromHtmlAsync(actor.Summary, hashtags: asHashtags)).Mfm;
+		}
+
 		var tags = ResolveHashtags(MfmParser.Parse(bio), actor);
 
 		user = new User
@@ -320,8 +330,18 @@ public class UserService(
 
 		var processPendingDeletes = await ResolveAvatarAndBannerAsync(user, actor);
 
-		user.UserProfile.Description = actor.MkSummary?.ReplaceLineEndings("\n").Trim()
+		user.UserProfile.Description = actor.MkSummary?.ReplaceLineEndings("\n").Trim();
-		                               ?? (await MfmConverter.FromHtmlAsync(actor.Summary)).Mfm;
+		if (user.UserProfile.Description == null)
+		{
+			var asHashtags = actor.Tags?.OfType<ASHashtag>()
+			                      .Select(p => p.Name?.ToLowerInvariant().TrimStart('#'))
+			                      .NotNull()
+			                      .ToList()
+			                 ?? [];
+
+			user.UserProfile.Description = (await MfmConverter.FromHtmlAsync(actor.Summary, hashtags: asHashtags)).Mfm;
+		}
+
 		//user.UserProfile.Birthday = TODO;
 		//user.UserProfile.Location = TODO;
 		user.UserProfile.Fields   = fields?.ToArray() ?? [];