plexbrainz/main.go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"strings"
	"time"
)

var lbToken string
var plexUsername string
var plexLibsStr string
var listen = ":9102"

func main() {

	lbToken = os.Getenv("PB_LISTENBRAINZ_USER_TOKEN")
	plexUsername = os.Getenv("PB_PLEX_USERNAME")
	plexLibsStr = os.Getenv("PB_PLEX_LIBRARIES")

	if lbToken == "" {
		log.Fatal("you must set PB_LISTENBRAINZ_USER_TOKEN - see https://listenbrainz.org/settings/")
	}

	if plexUsername == "" {
		log.Fatal("you must set PB_PLEX_USERNAME to the user who's listens will be recorded")
	}

	if plexLibsStr == "" {
		log.Fatal("you must set PB_PLEX_LIBRARIES to a comma separated list of plex libraries which will be scrobbled")
	}

	plexLibs := strings.Split(plexLibsStr, ",")

	http.HandleFunc("POST /plex", func(w http.ResponseWriter, r *http.Request) {
		err := r.ParseMultipartForm(1 * 1024 * 1024)
		if err != nil {
			log.Printf("error parsing multipart form: %s", err.Error())
			return
		}

		pl := r.FormValue("payload")
		event := webhookEvent{}
		err = json.Unmarshal([]byte(pl), &event)

		if err != nil {
			log.Printf("error parsing JSON: %s", err.Error())
			w.WriteHeader(400)
			w.Write([]byte("could not parse your JSON"))
			return
		}

		// log.Printf("event: %s", event.Event)
		// log.Printf("account name: %s", event.Account.Title)
		// log.Printf("title: %s", event.Metadata.Title)
		// log.Printf("album: %s", event.Metadata.ParentTitle)
		// log.Printf("artist: %s", event.Metadata.GrandparentTitle)
		// log.Printf("library: %s", event.Metadata.LibrarySectionTitle)

		// 2025/10/19 09:21:31 event: media.play
		// 2025/10/19 09:21:31 account name: username
		// 2025/10/19 09:21:31 title: Face to Face (Cosmo Vitelli remix)
		// 2025/10/19 09:21:31 album: Daft Club
		// 2025/10/19 09:21:31 artist: Daft Punk
		// 2025/10/19 09:21:31 library: Music
		if event.Account.Title != plexUsername {
			log.Printf("not scrobbling for user '%s'", plexUsername)
			w.WriteHeader(200)
			w.Write([]byte("ok"))
			return
		}

		if event.Event == "media.scrobble" {
			found := false
			for i := range plexLibs {
				if event.Metadata.LibrarySectionTitle == plexLibs[i] {
					found = true
					break
				}
			}
			if !found {
				log.Printf("not scrobbling for library '%s'", event.Metadata.LibrarySectionTitle)
				log.Printf("does not match one of: '%s'", plexLibsStr)
				w.WriteHeader(200)
				w.Write([]byte("ok"))
				return
			}

			err = lbSubmit(event.Metadata.Title, event.Metadata.GrandparentTitle, event.Metadata.ParentTitle)
			if err != nil {
				log.Printf("error submitting: %s", err.Error())
				w.WriteHeader(400)
				w.Write([]byte("could not parse your JSON"))
				return
			} else {
				log.Printf("scrobbled play of %s - %s", event.Metadata.GrandparentTitle, event.Metadata.Title)
				w.WriteHeader(200)
				w.Write([]byte("ok"))
				return
			}
		} else {
			log.Printf("non scrobble event: %s", event.Event)
			w.WriteHeader(200)
			w.Write([]byte("ok"))
			return
		}

	})
	log.Printf("starting web server on %s", listen)
	log.Fatal(http.ListenAndServe(listen, nil))
}

func lbSubmit(title, artist, album string) error {
	c := http.Client{}

	c.Timeout = time.Second * 10
	url := "https://api.listenbrainz.org/1/submit-listens"

	b := bytes.Buffer{}
	pl := lbListen{
		ListenType: "single",
		Payload: []lbListenPayload{{
			ListenedAt: time.Now().Unix(),
			TrackMetadata: lbTrackMetadata{
				ArtistName:  artist,
				TrackName:   title,
				ReleaseName: album,
			},
		}},
	}

	err := json.NewEncoder(&b).Encode(pl)
	if err != nil {
		return err
	}

	req, err := http.NewRequest("POST", url, bytes.NewBuffer(b.Bytes()))
	if err != nil {
		return err
	}
	req.Header.Set("Authorization", fmt.Sprintf("Token %s", lbToken))
	req.Header.Set("Content-Type", "application/json")

	res, err := c.Do(req)
	if err != nil {
		return err
	}
	defer res.Body.Close()

	if res.StatusCode != 200 {
		errB := bytes.Buffer{}
		io.Copy(&errB, res.Body)
		return fmt.Errorf("got non-200 response: %d - body: %s", res.StatusCode, errB.String())
	}

	// happy path
	return nil
}