From cf215b3d573360c0d6cc82eb5e76643551930632 Mon Sep 17 00:00:00 2001
From: Laura Hausmann <laura@hausmann.dev>
Date: Thu, 25 Apr 2024 19:13:57 +0200
Subject: [PATCH] [backend/federation] Handle ASDelete activities of ASNote
 objects

Some implementations seem to send deletes of ASNote objects instead of ASTombstone objects.
---
 .../ActivityPub/ActivityHandlerService.cs     |  6 +++++
 .../Core/Services/NoteService.cs              | 22 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs b/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs
index c69d4403..57f37af8 100644
--- a/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs
+++ b/Iceshrimp.Backend/Core/Federation/ActivityPub/ActivityHandlerService.cs
@@ -85,6 +85,12 @@ public class ActivityHandlerService(
 					return;
 				}
 
+				if (activity.Object is ASNote note)
+				{
+					await noteSvc.DeleteNoteAsync(note, resolvedActor);
+					return;
+				}
+
 				if (activity.Object is not ASTombstone tombstone)
 					throw GracefulException
 						.UnprocessableEntity($"Delete activity object is invalid: {activity.Object?.Type}");
diff --git a/Iceshrimp.Backend/Core/Services/NoteService.cs b/Iceshrimp.Backend/Core/Services/NoteService.cs
index 3ec6fa3c..fafdc9e5 100644
--- a/Iceshrimp.Backend/Core/Services/NoteService.cs
+++ b/Iceshrimp.Backend/Core/Services/NoteService.cs
@@ -569,6 +569,28 @@ public class NoteService(
 
 		await DeleteNoteAsync(dbNote);
 	}
+	
+	public async Task DeleteNoteAsync(ASNote note, User actor)
+	{
+		// ReSharper disable once EntityFramework.NPlusOne.IncompleteDataQuery (it doesn't know about IncludeCommonProperties())
+		var dbNote = await db.Notes.IncludeCommonProperties().FirstOrDefaultAsync(p => p.Uri == note.Id);
+		if (dbNote == null)
+		{
+			logger.LogDebug("Note '{id}' isn't known, skipping", note.Id);
+			return;
+		}
+
+		// ReSharper disable once EntityFramework.NPlusOne.IncompleteDataUsage (same reason as above)
+		if (dbNote.User != actor)
+		{
+			logger.LogDebug("Note '{id}' isn't owned by actor requesting its deletion, skipping", note.Id);
+			return;
+		}
+
+		logger.LogDebug("Deleting note '{id}' owned by {userId}", note.Id, actor.Id);
+
+		await DeleteNoteAsync(dbNote);
+	}
 
 	public async Task UndoAnnounceAsync(ASNote note, User actor)
 	{