Polling for available Unity Photon rooms with LoadBalancingClient while not in lobby?

Question

Using Unity, C# and Photon (PUN2), I have the user already connected to a room, but now want to (without that user leaving the room) retrieve a list of currently available other Photon rooms, including their current online user count (which can normally only be done pre- or post-room-join while in the lobby). Photon support tells me I need to create a second client using LoadBalancingClient for that, but I don't know exactly how. What would be the code skeleton for the basic Connect - PollAvailableRoomsAndOnlineCounts - Disconnect class and procedure? Thanks!

Answer 1

Found the answer in the meantime. Here's the skeleton code of my helper class PhotonRoomPoller.cs:

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Photon.Pun;
using Photon.Realtime;
using ExitGames.Client.Photon;

public class PhotonRoomPoller : MonoBehaviourPunCallbacks
{
    // Creates a second Photon peer to poll online room counts info.
    // A second peer is necessary as one otherwise while in a Room can't join
    // the Lobby, needed to get the room list. API at
    // doc-api.photonengine.com/en/pun/v2/class_photon_1_1_realtime_1_1_load_balancing_client.html

    Action<List<RoomInfo>> callback = null;
    LoadBalancingClient client = null;

    public void GetRoomsInfo(Action<List<RoomInfo>> callback)
    {
        this.callback = callback;

        client = new LoadBalancingClient();
        client.AddCallbackTarget(this);
        client.StateChanged += OnStateChanged;
        client.AppId = PhotonNetwork.PhotonServerSettings.AppSettings.AppIdRealtime;
        client.AppVersion = PhotonNetwork.NetworkingClient.AppVersion;
        client.ConnectToRegionMaster("us");
    }

    void Update()
    {
        if (client != null)
        {
            client.Service();
        }
    }

    void OnStateChanged(ClientState previousState, ClientState state)
    {
        // Debug.Log(state);
        if (state == ClientState.ConnectedToMaster)
        {
            client.OpJoinLobby(null);
        }
    }

    public override void OnRoomListUpdate(List<RoomInfo> infos)
    {
        if (callback != null)
        {
            callback(infos);
        }
        client.Disconnect();
    }

}

Usage, e.g.:

PhotonRoomPoller roomPoller = gameObject.AddComponent<PhotonRoomPoller>();
roomPoller.GetRoomsInfo
(
    (roomInfos) =>
    {
        AddContent(roomInfos);
        Destroy(roomPoller);
    }
);

Special care needs to be given to match all needed settings (though a lot can also remain null or undefined, e.g. gameVersion).