|string> */ public function rules(): array { return [ 'endpoint' => ['required', 'url', 'max:500'], 'keys.p256dh' => ['required', 'string', 'max:255'], 'keys.auth' => ['required', 'string', 'max:255'], 'expiration_time' => ['nullable'], 'content_encoding' => ['nullable', 'string', 'max:32'], 'device_id' => ['nullable', 'string', 'max:120'], ]; } }