[backend/federation] Resolve user profile mentions (ISH-33)

Iceshrimp.Backend/Controllers/Mastodon/Renderers/UserRenderer.cs

@@ -22,16 +22,19 @@ public class UserRenderer(IOptions<Config.InstanceSection> config, MfmConverter
 			acct += $"@{user.Host}";
 
 		var profileEmoji = emoji?.Where(p => user.Emojis.Contains(p.Id)).ToList() ?? await GetEmoji([user]);
-		var fields = profile?.Fields
+		var mentions     = profile?.Mentions ?? [];
-		                    .Select(p => new Field
+		var fields = profile != null
-		                    {
+			? await profile.Fields
-			                    Name  = p.Name,
+			               .Select(async p => new Field
-			                    Value = p.Value,
+			               {
-			                    VerifiedAt = p.IsVerified.HasValue && p.IsVerified.Value
+				               Name  = p.Name,
-				                    ? DateTime.Now.ToStringIso8601Like()
+				               Value = await mfmConverter.ToHtmlAsync(p.Value, mentions, user.Host),
-				                    : null
+				               VerifiedAt = p.IsVerified.HasValue && p.IsVerified.Value
-		                    })
+					               ? DateTime.Now.ToStringIso8601Like()
-		                    .ToList();
+					               : null
+			               })
+			               .AwaitAllAsync()
+			: null;
 
 		var res = new AccountEntity
 		{
@@ -46,7 +49,7 @@ public class UserRenderer(IOptions<Config.InstanceSection> config, MfmConverter
 			FollowersCount     = user.FollowersCount,
 			FollowingCount     = user.FollowingCount,
 			StatusesCount      = user.NotesCount,
-			Note               = await mfmConverter.ToHtmlAsync(profile?.Description ?? "", [], user.Host),
+			Note               = await mfmConverter.ToHtmlAsync(profile?.Description ?? "", mentions, user.Host),
 			Url                = profile?.Url ?? user.Uri ?? user.GetPublicUrl(config.Value),
 			AvatarStaticUrl    = user.AvatarUrl ?? user.GetIdenticonUrl(config.Value), //TODO
 			HeaderUrl          = user.BannerUrl ?? _transparent,
@@ -54,7 +57,7 @@ public class UserRenderer(IOptions<Config.InstanceSection> config, MfmConverter
 			MovedToAccount     = null,                           //TODO
 			IsBot              = user.IsBot,
 			IsDiscoverable     = user.IsExplorable,
-			Fields             = fields ?? [],
+			Fields             = fields?.ToList() ?? [],
 			Emoji              = profileEmoji
 		};
 

Iceshrimp.Backend/Core/Database/Tables/Note.cs

@@ -297,6 +297,6 @@ public class Note : IEntity
 		[J("uri")]      public required string  Uri      { get; set; }
 		[J("url")]      public          string? Url      { get; set; }
 		[J("username")] public required string  Username { get; set; }
-		[J("host")]     public required string  Host     { get; set; }
+		[J("host")]     public required string? Host     { get; set; }
 	}
 }

Iceshrimp.Backend/Core/Extensions/ServiceExtensions.cs

@@ -47,6 +47,7 @@ public static class ServiceExtensions
 			.AddScoped<DriveService>()
 			.AddScoped<NotificationService>()
 			.AddScoped<DatabaseMaintenanceService>()
+			.AddScoped<UserProfileMentionsResolver>()
 			.AddScoped<AuthorizedFetchMiddleware>()
 			.AddScoped<AuthenticationMiddleware>()
 			.AddScoped<ErrorHandlerMiddleware>()

Iceshrimp.Backend/Core/Extensions/StringExtensions.cs

@@ -6,10 +6,10 @@ namespace Iceshrimp.Backend.Core.Extensions;
 
 public static class StringExtensions
 {
-	public static bool EqualsInvariant(this string s1, string s2) =>
+	public static bool EqualsInvariant(this string? s1, string? s2) =>
 		string.Equals(s1, s2, StringComparison.InvariantCulture);
 
-	public static bool EqualsIgnoreCase(this string s1, string s2) =>
+	public static bool EqualsIgnoreCase(this string? s1, string s2) =>
 		string.Equals(s1, s2, StringComparison.InvariantCultureIgnoreCase);
 
 	public static string Truncate(this string target, int maxLength)

Iceshrimp.Backend/Core/Federation/ActivityPub/UserResolver.cs

@@ -133,6 +133,33 @@ public class UserResolver(
 		}
 	}
 
+	public async Task<User?> ResolveAsyncLimited(string query, Func<bool> limitReached)
+	{
+		query = NormalizeQuery(query);
+
+		// First, let's see if we already know the user
+		var user = await userSvc.GetUserFromQueryAsync(query);
+		if (user != null)
+			return await GetUpdatedUser(user);
+
+		// We don't, so we need to run WebFinger
+		var (acct, uri) = await WebFingerAsync(query);
+
+		// Check the database again with the new data
+		if (uri != query) user = await userSvc.GetUserFromQueryAsync(uri);
+		if (user == null && acct != query) await userSvc.GetUserFromQueryAsync(acct);
+		if (user != null)
+			return await GetUpdatedUser(user);
+
+		if (limitReached()) return null;
+
+		using (await KeyedLocker.LockAsync(uri))
+		{
+			// Pass the job on to userSvc, which will create the user
+			return await userSvc.CreateUserAsync(uri, acct);
+		}
+	}
+
 	private async Task<User> GetUpdatedUser(User user)
 	{
 		if (!user.NeedsUpdate) return user;

Iceshrimp.Backend/Core/Services/UserProfileMentionsResolver.cs

@@ -0,0 +1,70 @@
+using System.Diagnostics.CodeAnalysis;
+using Iceshrimp.Backend.Core.Configuration;
+using Iceshrimp.Backend.Core.Database.Tables;
+using Iceshrimp.Backend.Core.Extensions;
+using Iceshrimp.Backend.Core.Helpers.LibMfm.Parsing;
+using Iceshrimp.Backend.Core.Helpers.LibMfm.Types;
+using Microsoft.Extensions.Options;
+
+namespace Iceshrimp.Backend.Core.Services;
+
+public class UserProfileMentionsResolver(ActivityPub.UserResolver userResolver, IOptions<Config.InstanceSection> config)
+{
+	private int _recursionLimit = 10;
+
+	public async Task<List<Note.MentionedUser>> ResolveMentions(UserProfile.Field[]? fields, string? bio)
+	{
+		if (fields is not { Length: > 0 } && bio == null) return [];
+		var input = (fields ?? [])
+		            .SelectMany<UserProfile.Field, string>(p => [p.Name, p.Value])
+		            .Prepend(bio)
+		            .Where(p => p != null)
+		            .Cast<string>()
+		            .ToList();
+
+		var nodes        = input.SelectMany(p => MfmParser.Parse(p));
+		var mentionNodes = EnumerateMentions(nodes);
+		var users = await mentionNodes.DistinctBy(p => p.Acct)
+		                              .Select(async p =>
+		                              {
+			                              try
+			                              {
+				                              return await userResolver.ResolveAsyncLimited(p.Acct,
+					                              () => --_recursionLimit >= 0);
+			                              }
+			                              catch
+			                              {
+				                              return null;
+			                              }
+		                              })
+		                              .AwaitAllNoConcurrencyAsync();
+
+		return users.Where(p => p != null)
+		            .Cast<User>()
+		            .Select(p => new Note.MentionedUser
+		            {
+			            Host     = p.Host,
+			            Uri      = p.Uri ?? p.GetPublicUri(config.Value),
+			            Url      = p.UserProfile?.Url,
+			            Username = p.Username
+		            })
+		            .ToList();
+	}
+
+	[SuppressMessage("ReSharper", "ReturnTypeCanBeEnumerable.Local",
+	                 Justification = "Roslyn inspection says this hurts performance")]
+	private static List<MfmMentionNode> EnumerateMentions(IEnumerable<MfmNode> nodes)
+	{
+		var list = new List<MfmMentionNode>();
+
+		foreach (var node in nodes)
+		{
+			if (node is MfmMentionNode mention)
+				list.Add(mention);
+			else
+				list.AddRange(EnumerateMentions(node.Children));
+		}
+
+		return list;
+	}
+}

Iceshrimp.Backend/Core/Services/UserService.cs

@@ -107,6 +107,8 @@ public class UserService(
 		                  .Select(p => new UserProfile.Field { Name = p.Name!, Value = p.Value! })
 		                  .ToArray();
 
+		var bio = actor.MkSummary ?? await mfmConverter.FromHtmlAsync(actor.Summary);
+
 		user = new User
 		{
 			Id            = IdHelpers.GenerateSlowflakeId(),
@@ -136,7 +138,7 @@ public class UserService(
 		var profile = new UserProfile
 		{
 			User        = user,
-			Description = actor.MkSummary ?? await mfmConverter.FromHtmlAsync(actor.Summary),
+			Description = bio,
 			//Birthday = TODO,
 			//Location = TODO,
 			Fields   = fields ?? [],
@@ -157,6 +159,7 @@ public class UserService(
 			var processPendingDeletes = await ResolveAvatarAndBanner(user, actor);
 			await db.SaveChangesAsync();
 			await processPendingDeletes();
+			UpdateProfileMentionsInBackground(user);
 			return user;
 		}
 		catch (UniqueConstraintException)
@@ -256,6 +259,7 @@ public class UserService(
 		db.Update(user);
 		await db.SaveChangesAsync();
 		await processPendingDeletes();
+		UpdateProfileMentionsInBackground(user);
 		return user;
 	}
 
@@ -586,4 +590,22 @@ public class UserService(
 		// Clean up user list memberships
 		await db.UserListMembers.Where(p => p.UserList.User == user && p.User == followee).ExecuteDeleteAsync();
 	}
+
+	[SuppressMessage("ReSharper", "EntityFramework.NPlusOne.IncompleteDataQuery", Justification = "Projectables")]
+	[SuppressMessage("ReSharper", "EntityFramework.NPlusOne.IncompleteDataUsage", Justification = "Same as above")]
+	[SuppressMessage("ReSharper", "SuggestBaseTypeForParameter", Justification = "Method only makes sense for users")]
+	private void UpdateProfileMentionsInBackground(User user)
+	{
+		_ = followupTaskSvc.ExecuteTask("UpdateProfileMentionsInBackground", async provider =>
+		{
+			var bgDbContext = provider.GetRequiredService<DatabaseContext>();
+			var bgMentionsResolver = provider.GetRequiredService<UserProfileMentionsResolver>();
+			var bgUser = await bgDbContext.Users.IncludeCommonProperties().FirstOrDefaultAsync(p => p.Id == user.Id);
+			if (bgUser?.UserProfile == null) return;
+			bgUser.UserProfile.Mentions =
+				await bgMentionsResolver.ResolveMentions(bgUser.UserProfile.Fields, bgUser.UserProfile.Description);
+			bgDbContext.Update(bgUser.UserProfile);
+			await bgDbContext.SaveChangesAsync();
+		});
+	}
 }