Implement unfollow by remote account

src/remote/activitypub/act/undo/index.ts

@@ -0,0 +1,23 @@
+import act from '../../act';
+import unfollow from './unfollow';
+
+export default async (resolver, actor, activity) => {
+	if ('actor' in activity && actor.account.uri !== activity.actor) {
+		throw new Error();
+	}
+
+	const results = await act(resolver, actor, activity.object);
+
+	await Promise.all(results.map(async result => {
+		if (result === null) {
+			return;
+		}
+
+		switch (result.object.$ref) {
+		case 'following':
+			await unfollow(result.resolver, result.object);
+		}
+	}));
+
+	return null;
+};

src/remote/activitypub/act/undo/unfollow.ts

@@ -0,0 +1,24 @@
+import FollowedLog from '../../../../models/followed-log';
+import Following from '../../../../models/following';
+import FollowingLog from '../../../../models/following-log';
+import User from '../../../../models/user';
+
+export default async (resolver, { $id }) => {
+	const following = await Following.findOneAndDelete({ _id: $id });
+	if (following === null) {
+		return;
+	}
+
+	await Promise.all([
+		User.update({ _id: following.followerId }, { $inc: { followingCount: -1 } }),
+		User.findOne({ _id: following.followerId }).then(({ followingCount }) => FollowingLog.insert({
+			userId: following.followerId,
+			count: followingCount - 1
+		})),
+		User.update({ _id: following.followeeId }, { $inc: { followersCount: -1 } }),
+		User.findOne({ _id: following.followeeId }).then(({ followersCount }) => FollowedLog.insert({
+			userId: following.followeeId,
+			count: followersCount - 1
+		})),
+	]);
+};