Adding attributes for faceting with Algolia C#

Question

I have an attribute that I'd like to add for faceting: ApprovalFL. When I add the facet in the Algolia dashboard, it works fine until I have to reindex which ends up deleting my facets in the dashboard for some reason. I was thinking, maybe adding the attribute in my code would resolve that. I found the documentation about this step here: https://www.algolia.com/doc/api-reference/api-parameters/attributesForFaceting/

Here's the C# example they provide:

index.SetSettings(
  JObject.Parse(@"{""attributesForFaceting"":[""author"",""filterOnly(category)"",""searchable(publisher)""]}")
);

If I understand correctly, this code needs to go in my backend reindexing code (found in my AdminController.cs):

public async Task<ActionResult> ReIndexData()
{
    var algoliaArtistModels = Tools.BuildAlgoliaArtistModels(EntityDataAccess.GetAllAccountInfoes());
    var algoliaUnaffiliatedArtistModels = Tools.BuildAlgoliaArtistModels(EntityDataAccess.GetAllUnaffiliatedAccountInfo());
    var algoliaSongModels = Tools.BuildAlgoliaSongModels(EntityDataAccess.GetAllAcceptedSongs());
    var artistIndexHelper = HttpContext.Application.Get("ArtistIndexHelper") as IndexHelper<ArtistAlgoliaModel>;
    var unaffiliatedArtistIndexHelper = HttpContext.Application.Get("UnaffiliatedArtist") as IndexHelper<ArtistAlgoliaModel>;
    var songIndexHelper = HttpContext.Application.Get("SongIndexHelper") as IndexHelper<SongAlgoliaModel>;
    await artistIndexHelper.OverwriteIndexAsync(algoliaArtistModels);
    await unaffiliatedArtistIndexHelper.OverwriteIndexAsync(algoliaUnaffiliatedArtistModels);
    await songIndexHelper.OverwriteIndexAsync(algoliaSongModels);
    return View("AlgoliaReIndexData");
}

However, I don't think I put index.setSettings in this block of code, what is the best way to set this attribute for faceting in my backend code? The ApprovalFL attribute is stored in my Song indices.

Possibly it should go somewhere here in my Tools.cs?

public static SongAlgoliaModel BuildAlgoliaSongModel(Song song)
        {
            var model = new SongAlgoliaModel();
            var album = EntityDataAccess.GetAlbumByID(song.AlbumID);
            model.AccountImageURL = album.AccountInfo.ImageURL;
            model.AccountInfoID = album.AccountInfoID;
            model.AccountType = album.AccountInfo.CreatorFL == true ? "Creator" : "Artist";
            model.AlbumID = song.AlbumID;
            model.AlbumName = album.AlbumName;
            model.ApprovalFL = song.ApprovalFL;
            model.Artist = album.AccountInfo.DisplayName;
            model.BPM = song.BPM;
            model.Duration = song.Duration;
            model.FeaturedArtist = song.Artist;
            model.FreeFL = album.FreeFL;
            model.ImageURL = album.ImageURL;
            model.iTunesURL = album.iTunesURL;
            model.LabelName = album.LabelName;
            model.LicenseFL = album.LicenseFL;
            model.SongID = song.SongID;
            model.Title = song.Title;
            model.UploadDate = song.UploadDate;
            model.URL = song.URL;
            model.UserID = album.AccountInfo.UserID;

            return model;
        }
        public static List<SongAlgoliaModel> BuildAlgoliaSongModels(AccountInfo accountInfo)
        {
            var list = new List<SongAlgoliaModel>();
            var songs = EntityDataAccess.GetSongsByUserID(accountInfo.UserID).Where(x => x.ApprovalFL == true).ToList();
            foreach(var item in songs)
            {
                var model = new SongAlgoliaModel();
                model.AccountImageURL = item.Album.AccountInfo.ImageURL;
                model.AccountInfoID = item.Album.AccountInfoID;
                model.AccountType = item.Album.AccountInfo.CreatorFL == true ? "Creator" : "Artist";
                model.AlbumID = item.AlbumID;
                model.AlbumName = item.Album.AlbumName;
                model.ApprovalFL = item.ApprovalFL;
                model.Artist = item.Album.AccountInfo.DisplayName;
                model.BPM = item.BPM;
                model.Duration = item.Duration;
                model.FeaturedArtist = item.Artist;
                model.FreeFL = item.Album.FreeFL;
                model.ImageURL = item.Album.ImageURL;
                model.iTunesURL = item.Album.iTunesURL;
                model.LabelName = item.Album.LabelName;
                model.LicenseFL = item.Album.LicenseFL;
                model.SongID = item.SongID;
                model.Title = item.Title;
                model.UploadDate = item.UploadDate;
                model.URL = item.URL;
                model.UserID = item.Album.AccountInfo.UserID;
                list.Add(model);
            }
            return list;
        }

Answer 1

OK for those using C# .NET it's as simple as adding it to your Global.asax.cs for example for me:

var songIndexHelper = new IndexHelper<SongAlgoliaModel>(algoliaClient, "Song", "SongID");
songIndexHelper.SetSettings(JObject.Parse(@"{""attributesForFaceting"":[""ApprovalFL""]}"));

Answer 2

Why do you have to re-index by the way? Best practice is to set up your index only initially.