refactoring

Resolve #7779

packages/backend/src/services/instance-actor.ts

@@ -0,0 +1,27 @@
+import { createSystemUser } from './create-system-user';
+import { ILocalUser } from '@/models/entities/user';
+import { Users } from '@/models/index';
+import { Cache } from '@/misc/cache';
+
+const ACTOR_USERNAME = 'instance.actor' as const;
+
+const cache = new Cache<ILocalUser>(Infinity);
+
+export async function getInstanceActor(): Promise<ILocalUser> {
+	const cached = cache.get(null);
+	if (cached) return cached;
+
+	const user = await Users.findOne({
+		host: null,
+		username: ACTOR_USERNAME
+	}) as ILocalUser | undefined;
+
+	if (user) {
+		cache.set(null, user);
+		return user;
+	} else {
+		const created = await createSystemUser(ACTOR_USERNAME) as ILocalUser;
+		cache.set(null, created);
+		return created;
+	}
+}