From 06be4e108ba3edb71aa1362376660bc5dc9ee064 Mon Sep 17 00:00:00 2001
From: Laura Hausmann <laura@hausmann.dev>
Date: Sun, 10 Sep 2023 19:22:45 +0200
Subject: [PATCH] Fix updating remote user host for remote AP implementations
 that don't support webfinger uri queries

---
 .../src/remote/activitypub/models/person.ts   |  8 +++++---
 packages/backend/src/remote/resolve-user.ts   | 20 +++++++++++++++++++
 .../federation/update-remote-user.ts          |  2 +-
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/packages/backend/src/remote/activitypub/models/person.ts b/packages/backend/src/remote/activitypub/models/person.ts
index 4f913b50d..73743bec7 100644
--- a/packages/backend/src/remote/activitypub/models/person.ts
+++ b/packages/backend/src/remote/activitypub/models/person.ts
@@ -48,7 +48,7 @@ import Resolver from "../resolver.js";
 import { extractApHashtags } from "./tag.js";
 import { resolveNote, extractEmojis } from "./note.js";
 import { resolveImage } from "./image.js";
-import { getSubjectHostFromUri } from "@/remote/resolve-user.js"
+import { getSubjectHostFromUri, getSubjectHostFromRemoteUser } from "@/remote/resolve-user.js"
 
 const logger = apLogger;
 
@@ -425,11 +425,13 @@ export async function createPerson(
  * @param uri URI of Person
  * @param resolver Resolver
  * @param hint Hint of Person object (If this value is a valid Person, it is used for updating without Remote resolve)
+ * @param userHint Hint of IRemoteUser object, used for updating user information for remotes that only support webfinger with acct: query
  */
 export async function updatePerson(
 	uri: string,
 	resolver?: Resolver | null,
 	hint?: IObject,
+	userHint?: IRemoteUser,
 ): Promise<void> {
 	if (typeof uri !== "string") throw new Error("uri is not string");
 
@@ -452,10 +454,10 @@ export async function updatePerson(
 
 	const person = validateActor(object, uri);
 
-	const host = await getSubjectHostFromUri(uri);
-
 	logger.info(`Updating the Person: ${person.id}`);
 
+	const host = await getSubjectHostFromUri(uri) ?? await getSubjectHostFromRemoteUser(userHint);
+
 	// Fetch avatar and header image
 	const [avatar, banner] = await Promise.all(
 		[person.icon, person.image].map((img) =>
diff --git a/packages/backend/src/remote/resolve-user.ts b/packages/backend/src/remote/resolve-user.ts
index 7efaa26d6..b9edbd560 100644
--- a/packages/backend/src/remote/resolve-user.ts
+++ b/packages/backend/src/remote/resolve-user.ts
@@ -187,6 +187,26 @@ export async function getSubjectHostFromUri(uri: string): Promise<string | null>
 	}
 }
 
+export async function getSubjectHostFromAcct(acct: string): Promise<string | null> {
+	try {
+		const res = await resolveUserWebFinger(acct.toLowerCase());
+		const finalAcct = subjectToAcct(res.subject);
+		const m = finalAcct.match(/^([^@]+)@(.*)/);
+		if (!m) {
+			return null;
+		}
+		return m[2];
+	}
+	catch {
+		return null;
+	}
+}
+
+
+export async function getSubjectHostFromRemoteUser(user: IRemoteUser | undefined): Promise<string | null> {
+	return user ? getSubjectHostFromAcct(`${user.username}@${user.host}`) : null;
+}
+
 async function resolveUserWebFinger(acctLower: string, recurse: boolean = true): Promise<{
 	subject: string,
 	self: {
diff --git a/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts b/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts
index f4c3f6d18..9d6e4a7db 100644
--- a/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts
+++ b/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts
@@ -18,5 +18,5 @@ export const paramDef = {
 
 export default define(meta, paramDef, async (ps) => {
 	const user = await getRemoteUser(ps.userId);
-	await updatePerson(user.uri!);
+	await updatePerson(user.uri!, undefined, undefined, user);
 });