How to scrobble only primary artist to Last.fm

[PierreSenpai]

I use spotDL to download my Spotify playlists as local files and these seem to separate multiple artists with '/'. On Last.fm, the separation is also displayed with slashes, so I thought that I could use Scrobble Manipulation with regex to remove anything from artists that comes after the first slash (including it of course). No matter the combination, the regex doesn't find slashes. I then checked simpler regexes like "/word/i" and these do match, so they at least work in general. After that, I assumed that Multi-Scrobbler might 'split' the artists into singular artists to check the regex on, but contrary to that, there has been a fix specifically for scrobbling to Last.fm with just the primary artist (c648ad4).
Now, I'm at the point of total confusion and would really appreciate help.
Edit 1: I should add that i use Nodejs (22.13.1) and VLC (3.0.21)

[FoxxMD]

The commit you referenced for Last.fm is for when MS is scrobbling a track with multiple, well-formed artists already as proper list data IE

{
    "track": "My Track",
    "artists": [
        "Artist One",
        "Artist Two",
        "Artist Three"
    ],
    "album": "My Album"
}

In that case it will only send the first artist to Last.fm since last.fm doesn't support multiple artists (just one artist field in the scrobble request).

The data you are using still has all artists in the same field so MS doesn't know it's multiple artists IE

{
    "track": "My Track",
    "artists": [
        "Artist One / Artist Two / Artist Three"
    ],
    "album": "My Album"
}

It's not as simple as saying "MS should always separate the artist field based on this character" because artist names are non-trivial and can have any number of symbols, separators, or exceptions to how they are formed. MS is not opinionated about how the artist names should look, for this exact reason. It assumes whatever the Source player is sending is correct for artist names so it doesn't step on anyone's toes.

I thought that I could use Scrobble Manipulation with regex to remove anything from artists that comes after the first slash

This is feasible, though. And you were correct to try to use manipulations for this on the affected Source. I have added an example to the manipulation docs to show how this can be done (Extract primary Artist from delimited, multi-Artist string) and I've added a test case for it so you can be sure it is working.

Using your config from #258 the whole thing would look like this

{
    "sources": [
        {
            "type": "vlc",
            "enable": true,
            "name": "MyVlc",
            "data": {
                "url": "localhost:8080",
                "password": "123"
            },
            "options": {
                "playTransform": {
                    "preCompare": [
                        {
                            "artists": [
                                {
                                    "search": "(.*?)(?<delim>\\s*\\/\\s*)(.*$)",
                                    "replace": "$1"
                                }
                            ]
                        }
                    ]
                }
            }
        }
    ]
}

This will detected multiple, whitespace-buffered forward slashes (/) and replace the artist string with just the value before the first forward slash IE

Original => My Artist One / My Artist Two / Another Guy
Modified => My Artist One

It uses Regular Expressions which support javascript's string replace function with special placeholders.

Here is a regex example for it.

Be aware that in JSON backslashes have to be escaped so what is normally \s in regex needs to be \\s to work correctly.

---

On a related note though, MS does implement functionality to detect multiple artists from a single string, like you are dealing with, but it's only for Listenbrainz because MS can then verify if the detected values are correct against other LZ data. I will look into implementing this more generically as an option for all Sources so that if a user wants they can "aggressively" detect these patterns. It would likely cause false positives so it would be opt-in only but it seems like it would be helpful for scenarios like yours.

[PierreSenpai]

Nice, that's a big step towards my intended result. Based on your little hint, I assume that all my attempts on capturing the slash failed because I only tried placing one or no backslash in front of it but indeed two are needed.

I had to change your solution a bit, as I additionally have at least 2 artists that actually include a slash in their name ("K/DA" and "Miksu / Macloud"), so I refined my regex from yesterday (/(?<!^K)/[^ ].*/) with double backslashes and it works perfectly.

"preCompare": {
  "artists": [
    "/(?<!^K)\\/[^ ].*/"
  ]
}

Surely, this could be also handled with the "when" function, but I'm too lazy to change my config to that and just hope that I never come across an artist just named "K" doing a song with someone else or another artist that uses a none-whitespace-buffered slash.

To conclude, I'm very grateful for your quick and helpful responses on this and also my previous problems. I much appreciate your effort on this project and after finalizing the set-up and configuration, I am totally satisfied with it. <3