update

core/agents/lastfm/agent.go

@@ -0,0 +1,383 @@
+package lastfm
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/andybalholm/cascadia"
+	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/consts"
+	"github.com/navidrome/navidrome/core/agents"
+	"github.com/navidrome/navidrome/core/scrobbler"
+	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/utils/cache"
+	"golang.org/x/net/html"
+)
+
+const (
+	lastFMAgentName    = "lastfm"
+	sessionKeyProperty = "LastFMSessionKey"
+)
+
+var ignoredBiographies = []string{
+	// Unknown Artist
+	`<a href="https://www.last.fm/music/`,
+}
+
+type lastfmAgent struct {
+	ds           model.DataStore
+	sessionKeys  *agents.SessionKeys
+	apiKey       string
+	secret       string
+	lang         string
+	client       *client
+	httpClient   httpDoer
+	getInfoMutex sync.Mutex
+}
+
+func lastFMConstructor(ds model.DataStore) *lastfmAgent {
+	if !conf.Server.LastFM.Enabled || conf.Server.LastFM.ApiKey == "" || conf.Server.LastFM.Secret == "" {
+		return nil
+	}
+	l := &lastfmAgent{
+		ds:          ds,
+		lang:        conf.Server.LastFM.Language,
+		apiKey:      conf.Server.LastFM.ApiKey,
+		secret:      conf.Server.LastFM.Secret,
+		sessionKeys: &agents.SessionKeys{DataStore: ds, KeyName: sessionKeyProperty},
+	}
+	hc := &http.Client{
+		Timeout: consts.DefaultHttpClientTimeOut,
+	}
+	chc := cache.NewHTTPClient(hc, consts.DefaultHttpClientTimeOut)
+	l.httpClient = chc
+	l.client = newClient(l.apiKey, l.secret, l.lang, chc)
+	return l
+}
+
+func (l *lastfmAgent) AgentName() string {
+	return lastFMAgentName
+}
+
+var imageRegex = regexp.MustCompile(`u\/(\d+)`)
+
+func (l *lastfmAgent) GetAlbumInfo(ctx context.Context, name, artist, mbid string) (*agents.AlbumInfo, error) {
+	a, err := l.callAlbumGetInfo(ctx, name, artist, mbid)
+	if err != nil {
+		return nil, err
+	}
+
+	return &agents.AlbumInfo{
+		Name:        a.Name,
+		MBID:        a.MBID,
+		Description: a.Description.Summary,
+		URL:         a.URL,
+	}, nil
+}
+
+func (l *lastfmAgent) GetAlbumImages(ctx context.Context, name, artist, mbid string) ([]agents.ExternalImage, error) {
+	a, err := l.callAlbumGetInfo(ctx, name, artist, mbid)
+	if err != nil {
+		return nil, err
+	}
+
+	// Last.fm can return duplicate sizes.
+	seenSizes := map[int]bool{}
+	images := make([]agents.ExternalImage, 0)
+
+	// This assumes that Last.fm returns images with size small, medium, and large.
+	// This is true as of December 29, 2022
+	for _, img := range a.Image {
+		size := imageRegex.FindStringSubmatch(img.URL)
+		// Last.fm can return images without URL
+		if len(size) == 0 || len(size[0]) < 4 {
+			log.Trace(ctx, "LastFM/albuminfo image URL does not match expected regex or is empty", "url", img.URL, "size", img.Size)
+			continue
+		}
+		numericSize, err := strconv.Atoi(size[0][2:])
+		if err != nil {
+			log.Error(ctx, "LastFM/albuminfo image URL does not match expected regex", "url", img.URL, "size", img.Size, err)
+			return nil, err
+		}
+		if _, exists := seenSizes[numericSize]; !exists {
+			images = append(images, agents.ExternalImage{
+				Size: numericSize,
+				URL:  img.URL,
+			})
+			seenSizes[numericSize] = true
+		}
+	}
+	return images, nil
+}
+
+func (l *lastfmAgent) GetArtistMBID(ctx context.Context, id string, name string) (string, error) {
+	a, err := l.callArtistGetInfo(ctx, name)
+	if err != nil {
+		return "", err
+	}
+	if a.MBID == "" {
+		return "", agents.ErrNotFound
+	}
+	return a.MBID, nil
+}
+
+func (l *lastfmAgent) GetArtistURL(ctx context.Context, id, name, mbid string) (string, error) {
+	a, err := l.callArtistGetInfo(ctx, name)
+	if err != nil {
+		return "", err
+	}
+	if a.URL == "" {
+		return "", agents.ErrNotFound
+	}
+	return a.URL, nil
+}
+
+func (l *lastfmAgent) GetArtistBiography(ctx context.Context, id, name, mbid string) (string, error) {
+	a, err := l.callArtistGetInfo(ctx, name)
+	if err != nil {
+		return "", err
+	}
+	a.Bio.Summary = strings.TrimSpace(a.Bio.Summary)
+	if a.Bio.Summary == "" {
+		return "", agents.ErrNotFound
+	}
+	for _, ign := range ignoredBiographies {
+		if strings.HasPrefix(a.Bio.Summary, ign) {
+			return "", nil
+		}
+	}
+	return a.Bio.Summary, nil
+}
+
+func (l *lastfmAgent) GetSimilarArtists(ctx context.Context, id, name, mbid string, limit int) ([]agents.Artist, error) {
+	resp, err := l.callArtistGetSimilar(ctx, name, limit)
+	if err != nil {
+		return nil, err
+	}
+	if len(resp) == 0 {
+		return nil, agents.ErrNotFound
+	}
+	var res []agents.Artist
+	for _, a := range resp {
+		res = append(res, agents.Artist{
+			Name: a.Name,
+			MBID: a.MBID,
+		})
+	}
+	return res, nil
+}
+
+func (l *lastfmAgent) GetArtistTopSongs(ctx context.Context, id, artistName, mbid string, count int) ([]agents.Song, error) {
+	resp, err := l.callArtistGetTopTracks(ctx, artistName, count)
+	if err != nil {
+		return nil, err
+	}
+	if len(resp) == 0 {
+		return nil, agents.ErrNotFound
+	}
+	var res []agents.Song
+	for _, t := range resp {
+		res = append(res, agents.Song{
+			Name: t.Name,
+			MBID: t.MBID,
+		})
+	}
+	return res, nil
+}
+
+var (
+	artistOpenGraphQuery = cascadia.MustCompile(`html > head > meta[property="og:image"]`)
+	artistIgnoredImage   = "2a96cbd8b46e442fc41c2b86b821562f" // Last.fm artist placeholder image name
+)
+
+func (l *lastfmAgent) GetArtistImages(ctx context.Context, _, name, mbid string) ([]agents.ExternalImage, error) {
+	log.Debug(ctx, "Getting artist images from Last.fm", "name", name)
+	a, err := l.callArtistGetInfo(ctx, name)
+	if err != nil {
+		return nil, fmt.Errorf("get artist info: %w", err)
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, a.URL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("create artist image request: %w", err)
+	}
+	resp, err := l.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("get artist url: %w", err)
+	}
+	defer resp.Body.Close()
+
+	node, err := html.Parse(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("parse html: %w", err)
+	}
+
+	var res []agents.ExternalImage
+	n := cascadia.Query(node, artistOpenGraphQuery)
+	if n == nil {
+		return res, nil
+	}
+	for _, attr := range n.Attr {
+		if attr.Key != "content" {
+			continue
+		}
+		if strings.Contains(attr.Val, artistIgnoredImage) {
+			log.Debug(ctx, "Artist image is ignored default image", "name", name, "url", attr.Val)
+			return res, nil
+		}
+
+		res = []agents.ExternalImage{
+			{URL: attr.Val},
+		}
+	}
+	return res, nil
+}
+
+func (l *lastfmAgent) callAlbumGetInfo(ctx context.Context, name, artist, mbid string) (*Album, error) {
+	a, err := l.client.albumGetInfo(ctx, name, artist, mbid)
+	var lfErr *lastFMError
+	isLastFMError := errors.As(err, &lfErr)
+
+	if mbid != "" && (isLastFMError && lfErr.Code == 6) {
+		log.Debug(ctx, "LastFM/album.getInfo could not find album by mbid, trying again", "album", name, "mbid", mbid)
+		return l.callAlbumGetInfo(ctx, name, artist, "")
+	}
+
+	if err != nil {
+		if isLastFMError && lfErr.Code == 6 {
+			log.Debug(ctx, "Album not found", "album", name, "mbid", mbid, err)
+		} else {
+			log.Error(ctx, "Error calling LastFM/album.getInfo", "album", name, "mbid", mbid, err)
+		}
+		return nil, err
+	}
+	return a, nil
+}
+
+func (l *lastfmAgent) callArtistGetInfo(ctx context.Context, name string) (*Artist, error) {
+	l.getInfoMutex.Lock()
+	defer l.getInfoMutex.Unlock()
+
+	a, err := l.client.artistGetInfo(ctx, name)
+	if err != nil {
+		log.Error(ctx, "Error calling LastFM/artist.getInfo", "artist", name, err)
+		return nil, err
+	}
+	return a, nil
+}
+
+func (l *lastfmAgent) callArtistGetSimilar(ctx context.Context, name string, limit int) ([]Artist, error) {
+	s, err := l.client.artistGetSimilar(ctx, name, limit)
+	if err != nil {
+		log.Error(ctx, "Error calling LastFM/artist.getSimilar", "artist", name, err)
+		return nil, err
+	}
+	return s.Artists, nil
+}
+
+func (l *lastfmAgent) callArtistGetTopTracks(ctx context.Context, artistName string, count int) ([]Track, error) {
+	t, err := l.client.artistGetTopTracks(ctx, artistName, count)
+	if err != nil {
+		log.Error(ctx, "Error calling LastFM/artist.getTopTracks", "artist", artistName, err)
+		return nil, err
+	}
+	return t.Track, nil
+}
+
+func (l *lastfmAgent) getArtistForScrobble(track *model.MediaFile, role model.Role, displayName string) string {
+	if conf.Server.LastFM.ScrobbleFirstArtistOnly && len(track.Participants[role]) > 0 {
+		return track.Participants[role][0].Name
+	}
+	return displayName
+}
+
+func (l *lastfmAgent) NowPlaying(ctx context.Context, userId string, track *model.MediaFile, position int) error {
+	sk, err := l.sessionKeys.Get(ctx, userId)
+	if err != nil || sk == "" {
+		return scrobbler.ErrNotAuthorized
+	}
+
+	err = l.client.updateNowPlaying(ctx, sk, ScrobbleInfo{
+		artist:      l.getArtistForScrobble(track, model.RoleArtist, track.Artist),
+		track:       track.Title,
+		album:       track.Album,
+		trackNumber: track.TrackNumber,
+		mbid:        track.MbzRecordingID,
+		duration:    int(track.Duration),
+		albumArtist: l.getArtistForScrobble(track, model.RoleAlbumArtist, track.AlbumArtist),
+	})
+	if err != nil {
+		log.Warn(ctx, "Last.fm client.updateNowPlaying returned error", "track", track.Title, err)
+		return errors.Join(err, scrobbler.ErrUnrecoverable)
+	}
+	return nil
+}
+
+func (l *lastfmAgent) Scrobble(ctx context.Context, userId string, s scrobbler.Scrobble) error {
+	sk, err := l.sessionKeys.Get(ctx, userId)
+	if err != nil || sk == "" {
+		return errors.Join(err, scrobbler.ErrNotAuthorized)
+	}
+
+	if s.Duration <= 30 {
+		log.Debug(ctx, "Skipping Last.fm scrobble for short song", "track", s.Title, "duration", s.Duration)
+		return nil
+	}
+	err = l.client.scrobble(ctx, sk, ScrobbleInfo{
+		artist:      l.getArtistForScrobble(&s.MediaFile, model.RoleArtist, s.Artist),
+		track:       s.Title,
+		album:       s.Album,
+		trackNumber: s.TrackNumber,
+		mbid:        s.MbzRecordingID,
+		duration:    int(s.Duration),
+		albumArtist: l.getArtistForScrobble(&s.MediaFile, model.RoleAlbumArtist, s.AlbumArtist),
+		timestamp:   s.TimeStamp,
+	})
+	if err == nil {
+		return nil
+	}
+	var lfErr *lastFMError
+	isLastFMError := errors.As(err, &lfErr)
+	if !isLastFMError {
+		log.Warn(ctx, "Last.fm client.scrobble returned error", "track", s.Title, err)
+		return errors.Join(err, scrobbler.ErrRetryLater)
+	}
+	if lfErr.Code == 11 || lfErr.Code == 16 {
+		return errors.Join(err, scrobbler.ErrRetryLater)
+	}
+	return errors.Join(err, scrobbler.ErrUnrecoverable)
+}
+
+func (l *lastfmAgent) IsAuthorized(ctx context.Context, userId string) bool {
+	sk, err := l.sessionKeys.Get(ctx, userId)
+	return err == nil && sk != ""
+}
+
+func init() {
+	conf.AddHook(func() {
+		agents.Register(lastFMAgentName, func(ds model.DataStore) agents.Interface {
+			// This is a workaround for the fact that a (Interface)(nil) is not the same as a (*lastfmAgent)(nil)
+			// See https://go.dev/doc/faq#nil_error
+			a := lastFMConstructor(ds)
+			if a != nil {
+				return a
+			}
+			return nil
+		})
+		scrobbler.Register(lastFMAgentName, func(ds model.DataStore) scrobbler.Scrobbler {
+			// Same as above - this is a workaround for the fact that a (Scrobbler)(nil) is not the same as a (*lastfmAgent)(nil)
+			// See https://go.dev/doc/faq#nil_error
+			a := lastFMConstructor(ds)
+			if a != nil {
+				return a
+			}
+			return nil
+		})
+	})
+}

core/agents/lastfm/agent_test.go

@@ -0,0 +1,487 @@
+package lastfm
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"os"
+	"strconv"
+	"time"
+
+	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/conf/configtest"
+	"github.com/navidrome/navidrome/core/agents"
+	"github.com/navidrome/navidrome/core/scrobbler"
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+const (
+	lastfmError3 = `{"error":3,"message":"Invalid Method - No method with that name in this package","links":[]}`
+	lastfmError6 = `{"error":6,"message":"The artist you supplied could not be found","links":[]}`
+)
+
+var _ = Describe("lastfmAgent", func() {
+	var ds model.DataStore
+	var ctx context.Context
+	BeforeEach(func() {
+		ds = &tests.MockDataStore{}
+		ctx = context.Background()
+		DeferCleanup(configtest.SetupConfig())
+		conf.Server.LastFM.Enabled = true
+		conf.Server.LastFM.ApiKey = "123"
+		conf.Server.LastFM.Secret = "secret"
+	})
+	Describe("lastFMConstructor", func() {
+		When("Agent is properly configured", func() {
+			It("uses configured api key and language", func() {
+				conf.Server.LastFM.Language = "pt"
+				agent := lastFMConstructor(ds)
+				Expect(agent.apiKey).To(Equal("123"))
+				Expect(agent.secret).To(Equal("secret"))
+				Expect(agent.lang).To(Equal("pt"))
+			})
+		})
+		When("Agent is disabled", func() {
+			It("returns nil", func() {
+				conf.Server.LastFM.Enabled = false
+				Expect(lastFMConstructor(ds)).To(BeNil())
+			})
+		})
+		When("ApiKey is empty", func() {
+			It("returns nil", func() {
+				conf.Server.LastFM.ApiKey = ""
+				Expect(lastFMConstructor(ds)).To(BeNil())
+			})
+		})
+		When("Secret is empty", func() {
+			It("returns nil", func() {
+				conf.Server.LastFM.Secret = ""
+				Expect(lastFMConstructor(ds)).To(BeNil())
+			})
+		})
+	})
+
+	Describe("GetArtistBiography", func() {
+		var agent *lastfmAgent
+		var httpClient *tests.FakeHttpClient
+		BeforeEach(func() {
+			httpClient = &tests.FakeHttpClient{}
+			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			agent = lastFMConstructor(ds)
+			agent.client = client
+		})
+
+		It("returns the biography", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+			Expect(agent.GetArtistBiography(ctx, "123", "U2", "")).To(Equal("U2 é uma das mais importantes bandas de rock de todos os tempos. Formada em 1976 em Dublin, composta por Bono (vocalista  e guitarrista), The Edge (guitarrista, pianista e backing vocal), Adam Clayton (baixista), Larry Mullen, Jr. (baterista e percussionista).\n\nDesde a década de 80, U2 é uma das bandas mais populares no mundo. Seus shows são únicos e um verdadeiro festival de efeitos especiais, além de serem um dos que mais arrecadam anualmente. <a href=\"https://www.last.fm/music/U2\">Read more on Last.fm</a>"))
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+
+		It("returns an error if Last.fm call fails", func() {
+			httpClient.Err = errors.New("error")
+			_, err := agent.GetArtistBiography(ctx, "123", "U2", "")
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+
+		It("returns an error if Last.fm call returns an error", func() {
+			httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString(lastfmError3)), StatusCode: 200}
+			_, err := agent.GetArtistBiography(ctx, "123", "U2", "")
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+	})
+
+	Describe("GetSimilarArtists", func() {
+		var agent *lastfmAgent
+		var httpClient *tests.FakeHttpClient
+		BeforeEach(func() {
+			httpClient = &tests.FakeHttpClient{}
+			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			agent = lastFMConstructor(ds)
+			agent.client = client
+		})
+
+		It("returns similar artists", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.artist.getsimilar.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+			Expect(agent.GetSimilarArtists(ctx, "123", "U2", "", 2)).To(Equal([]agents.Artist{
+				{Name: "Passengers", MBID: "e110c11f-1c94-4471-a350-c38f46b29389"},
+				{Name: "INXS", MBID: "481bf5f9-2e7c-4c44-b08a-05b32bc7c00d"},
+			}))
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+
+		It("returns an error if Last.fm call fails", func() {
+			httpClient.Err = errors.New("error")
+			_, err := agent.GetSimilarArtists(ctx, "123", "U2", "", 2)
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+
+		It("returns an error if Last.fm call returns an error", func() {
+			httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString(lastfmError3)), StatusCode: 200}
+			_, err := agent.GetSimilarArtists(ctx, "123", "U2", "", 2)
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+	})
+
+	Describe("GetArtistTopSongs", func() {
+		var agent *lastfmAgent
+		var httpClient *tests.FakeHttpClient
+		BeforeEach(func() {
+			httpClient = &tests.FakeHttpClient{}
+			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			agent = lastFMConstructor(ds)
+			agent.client = client
+		})
+
+		It("returns top songs", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.artist.gettoptracks.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+			Expect(agent.GetArtistTopSongs(ctx, "123", "U2", "", 2)).To(Equal([]agents.Song{
+				{Name: "Beautiful Day", MBID: "f7f264d0-a89b-4682-9cd7-a4e7c37637af"},
+				{Name: "With or Without You", MBID: "6b9a509f-6907-4a6e-9345-2f12da09ba4b"},
+			}))
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+
+		It("returns an error if Last.fm call fails", func() {
+			httpClient.Err = errors.New("error")
+			_, err := agent.GetArtistTopSongs(ctx, "123", "U2", "", 2)
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+
+		It("returns an error if Last.fm call returns an error", func() {
+			httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString(lastfmError3)), StatusCode: 200}
+			_, err := agent.GetArtistTopSongs(ctx, "123", "U2", "", 2)
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("artist")).To(Equal("U2"))
+		})
+	})
+
+	Describe("Scrobbling", func() {
+		var agent *lastfmAgent
+		var httpClient *tests.FakeHttpClient
+		var track *model.MediaFile
+		BeforeEach(func() {
+			_ = ds.UserProps(ctx).Put("user-1", sessionKeyProperty, "SK-1")
+			httpClient = &tests.FakeHttpClient{}
+			client := newClient("API_KEY", "SECRET", "en", httpClient)
+			agent = lastFMConstructor(ds)
+			agent.client = client
+			track = &model.MediaFile{
+				ID:             "123",
+				Title:          "Track Title",
+				Album:          "Track Album",
+				Artist:         "Track Artist",
+				AlbumArtist:    "Track AlbumArtist",
+				TrackNumber:    1,
+				Duration:       180,
+				MbzRecordingID: "mbz-123",
+				Participants: map[model.Role]model.ParticipantList{
+					model.RoleArtist: []model.Participant{
+						{Artist: model.Artist{ID: "ar-1", Name: "First Artist"}},
+						{Artist: model.Artist{ID: "ar-2", Name: "Second Artist"}},
+					},
+					model.RoleAlbumArtist: []model.Participant{
+						{Artist: model.Artist{ID: "ar-1", Name: "First Album Artist"}},
+						{Artist: model.Artist{ID: "ar-2", Name: "Second Album Artist"}},
+					},
+				},
+			}
+		})
+
+		Describe("NowPlaying", func() {
+			It("calls Last.fm with correct params", func() {
+				httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString("{}")), StatusCode: 200}
+
+				err := agent.NowPlaying(ctx, "user-1", track, 0)
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(httpClient.SavedRequest.Method).To(Equal(http.MethodPost))
+				sentParams := httpClient.SavedRequest.URL.Query()
+				Expect(sentParams.Get("method")).To(Equal("track.updateNowPlaying"))
+				Expect(sentParams.Get("sk")).To(Equal("SK-1"))
+				Expect(sentParams.Get("track")).To(Equal(track.Title))
+				Expect(sentParams.Get("album")).To(Equal(track.Album))
+				Expect(sentParams.Get("artist")).To(Equal(track.Artist))
+				Expect(sentParams.Get("albumArtist")).To(Equal(track.AlbumArtist))
+				Expect(sentParams.Get("trackNumber")).To(Equal(strconv.Itoa(track.TrackNumber)))
+				Expect(sentParams.Get("duration")).To(Equal(strconv.FormatFloat(float64(track.Duration), 'G', -1, 32)))
+				Expect(sentParams.Get("mbid")).To(Equal(track.MbzRecordingID))
+			})
+
+			It("returns ErrNotAuthorized if user is not linked", func() {
+				err := agent.NowPlaying(ctx, "user-2", track, 0)
+				Expect(err).To(MatchError(scrobbler.ErrNotAuthorized))
+			})
+
+			When("ScrobbleFirstArtistOnly is true", func() {
+				BeforeEach(func() {
+					conf.Server.LastFM.ScrobbleFirstArtistOnly = true
+				})
+
+				It("uses only the first artist", func() {
+					httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString("{}")), StatusCode: 200}
+
+					err := agent.NowPlaying(ctx, "user-1", track, 0)
+
+					Expect(err).ToNot(HaveOccurred())
+					sentParams := httpClient.SavedRequest.URL.Query()
+					Expect(sentParams.Get("artist")).To(Equal("First Artist"))
+					Expect(sentParams.Get("albumArtist")).To(Equal("First Album Artist"))
+				})
+			})
+		})
+
+		Describe("scrobble", func() {
+			It("calls Last.fm with correct params", func() {
+				ts := time.Now()
+				httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString("{}")), StatusCode: 200}
+
+				err := agent.Scrobble(ctx, "user-1", scrobbler.Scrobble{MediaFile: *track, TimeStamp: ts})
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(httpClient.SavedRequest.Method).To(Equal(http.MethodPost))
+				sentParams := httpClient.SavedRequest.URL.Query()
+				Expect(sentParams.Get("method")).To(Equal("track.scrobble"))
+				Expect(sentParams.Get("sk")).To(Equal("SK-1"))
+				Expect(sentParams.Get("track")).To(Equal(track.Title))
+				Expect(sentParams.Get("album")).To(Equal(track.Album))
+				Expect(sentParams.Get("artist")).To(Equal(track.Artist))
+				Expect(sentParams.Get("albumArtist")).To(Equal(track.AlbumArtist))
+				Expect(sentParams.Get("trackNumber")).To(Equal(strconv.Itoa(track.TrackNumber)))
+				Expect(sentParams.Get("duration")).To(Equal(strconv.FormatFloat(float64(track.Duration), 'G', -1, 32)))
+				Expect(sentParams.Get("mbid")).To(Equal(track.MbzRecordingID))
+				Expect(sentParams.Get("timestamp")).To(Equal(strconv.FormatInt(ts.Unix(), 10)))
+			})
+
+			When("ScrobbleFirstArtistOnly is true", func() {
+				BeforeEach(func() {
+					conf.Server.LastFM.ScrobbleFirstArtistOnly = true
+				})
+
+				It("uses only the first artist", func() {
+					ts := time.Now()
+					httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString("{}")), StatusCode: 200}
+
+					err := agent.Scrobble(ctx, "user-1", scrobbler.Scrobble{MediaFile: *track, TimeStamp: ts})
+
+					Expect(err).ToNot(HaveOccurred())
+					sentParams := httpClient.SavedRequest.URL.Query()
+					Expect(sentParams.Get("artist")).To(Equal("First Artist"))
+					Expect(sentParams.Get("albumArtist")).To(Equal("First Album Artist"))
+				})
+			})
+
+			It("skips songs with less than 31 seconds", func() {
+				track.Duration = 29
+				httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString("{}")), StatusCode: 200}
+
+				err := agent.Scrobble(ctx, "user-1", scrobbler.Scrobble{MediaFile: *track, TimeStamp: time.Now()})
+
+				Expect(err).ToNot(HaveOccurred())
+				Expect(httpClient.SavedRequest).To(BeNil())
+			})
+
+			It("returns ErrNotAuthorized if user is not linked", func() {
+				err := agent.Scrobble(ctx, "user-2", scrobbler.Scrobble{MediaFile: *track, TimeStamp: time.Now()})
+				Expect(err).To(MatchError(scrobbler.ErrNotAuthorized))
+			})
+
+			It("returns ErrRetryLater on error 11", func() {
+				httpClient.Res = http.Response{
+					Body:       io.NopCloser(bytes.NewBufferString(`{"error":11,"message":"Service Offline - This service is temporarily offline. Try again later."}`)),
+					StatusCode: 400,
+				}
+
+				err := agent.Scrobble(ctx, "user-1", scrobbler.Scrobble{MediaFile: *track, TimeStamp: time.Now()})
+				Expect(err).To(MatchError(scrobbler.ErrRetryLater))
+			})
+
+			It("returns ErrRetryLater on error 16", func() {
+				httpClient.Res = http.Response{
+					Body:       io.NopCloser(bytes.NewBufferString(`{"error":16,"message":"There was a temporary error processing your request. Please try again"}`)),
+					StatusCode: 400,
+				}
+
+				err := agent.Scrobble(ctx, "user-1", scrobbler.Scrobble{MediaFile: *track, TimeStamp: time.Now()})
+				Expect(err).To(MatchError(scrobbler.ErrRetryLater))
+			})
+
+			It("returns ErrRetryLater on http errors", func() {
+				httpClient.Res = http.Response{
+					Body:       io.NopCloser(bytes.NewBufferString(`internal server error`)),
+					StatusCode: 500,
+				}
+
+				err := agent.Scrobble(ctx, "user-1", scrobbler.Scrobble{MediaFile: *track, TimeStamp: time.Now()})
+				Expect(err).To(MatchError(scrobbler.ErrRetryLater))
+			})
+
+			It("returns ErrUnrecoverable on other errors", func() {
+				httpClient.Res = http.Response{
+					Body:       io.NopCloser(bytes.NewBufferString(`{"error":8,"message":"Operation failed - Something else went wrong"}`)),
+					StatusCode: 400,
+				}
+
+				err := agent.Scrobble(ctx, "user-1", scrobbler.Scrobble{MediaFile: *track, TimeStamp: time.Now()})
+				Expect(err).To(MatchError(scrobbler.ErrUnrecoverable))
+			})
+		})
+	})
+
+	Describe("GetAlbumInfo", func() {
+		var agent *lastfmAgent
+		var httpClient *tests.FakeHttpClient
+		BeforeEach(func() {
+			httpClient = &tests.FakeHttpClient{}
+			client := newClient("API_KEY", "SECRET", "pt", httpClient)
+			agent = lastFMConstructor(ds)
+			agent.client = client
+		})
+
+		It("returns the biography", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.album.getinfo.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+			Expect(agent.GetAlbumInfo(ctx, "Believe", "Cher", "03c91c40-49a6-44a7-90e7-a700edf97a62")).To(Equal(&agents.AlbumInfo{
+				Name:        "Believe",
+				MBID:        "03c91c40-49a6-44a7-90e7-a700edf97a62",
+				Description: "Believe is the twenty-third studio album by American singer-actress Cher, released on November 10, 1998 by Warner Bros. Records. The RIAA certified it Quadruple Platinum on December 23, 1999, recognizing four million shipments in the United States; Worldwide, the album has sold more than 20 million copies, making it the biggest-selling album of her career. In 1999 the album received three Grammy Awards nominations including \"Record of the Year\", \"Best Pop Album\" and winning \"Best Dance Recording\" for the single \"Believe\". It was released by Warner Bros. Records at the end of 1998. The album was executive produced by Rob <a href=\"https://www.last.fm/music/Cher/Believe\">Read more on Last.fm</a>.",
+				URL:         "https://www.last.fm/music/Cher/Believe",
+			}))
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("mbid")).To(Equal("03c91c40-49a6-44a7-90e7-a700edf97a62"))
+		})
+
+		It("returns empty images if no images are available", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.album.getinfo.empty_urls.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+			Expect(agent.GetAlbumInfo(ctx, "The Definitive Less Damage And More Joy", "The Jesus and Mary Chain", "")).To(Equal(&agents.AlbumInfo{
+				Name: "The Definitive Less Damage And More Joy",
+				URL:  "https://www.last.fm/music/The+Jesus+and+Mary+Chain/The+Definitive+Less+Damage+And+More+Joy",
+			}))
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("album")).To(Equal("The Definitive Less Damage And More Joy"))
+		})
+
+		It("returns an error if Last.fm call fails", func() {
+			httpClient.Err = errors.New("error")
+			_, err := agent.GetAlbumInfo(ctx, "123", "U2", "mbid-1234")
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("mbid")).To(Equal("mbid-1234"))
+		})
+
+		It("returns an error if Last.fm call returns an error", func() {
+			httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString(lastfmError3)), StatusCode: 200}
+			_, err := agent.GetAlbumInfo(ctx, "123", "U2", "mbid-1234")
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+			Expect(httpClient.SavedRequest.URL.Query().Get("mbid")).To(Equal("mbid-1234"))
+		})
+
+		It("returns an error if Last.fm call returns an error 6 and mbid is empty", func() {
+			httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString(lastfmError6)), StatusCode: 200}
+			_, err := agent.GetAlbumInfo(ctx, "123", "U2", "")
+			Expect(err).To(HaveOccurred())
+			Expect(httpClient.RequestCount).To(Equal(1))
+		})
+
+		Context("MBID non existent in Last.fm", func() {
+			It("calls again when last.fm returns an error 6", func() {
+				httpClient.Res = http.Response{Body: io.NopCloser(bytes.NewBufferString(lastfmError6)), StatusCode: 200}
+				_, _ = agent.GetAlbumInfo(ctx, "123", "U2", "mbid-1234")
+				Expect(httpClient.RequestCount).To(Equal(2))
+				Expect(httpClient.SavedRequest.URL.Query().Get("mbid")).To(BeEmpty())
+			})
+		})
+	})
+
+	Describe("GetArtistImages", func() {
+		var agent *lastfmAgent
+		var apiClient *tests.FakeHttpClient
+		var httpClient *tests.FakeHttpClient
+
+		BeforeEach(func() {
+			apiClient = &tests.FakeHttpClient{}
+			httpClient = &tests.FakeHttpClient{}
+			client := newClient("API_KEY", "SECRET", "pt", apiClient)
+			agent = lastFMConstructor(ds)
+			agent.client = client
+			agent.httpClient = httpClient
+		})
+
+		It("returns the artist image from the page", func() {
+			fApi, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+			apiClient.Res = http.Response{Body: fApi, StatusCode: 200}
+
+			fScraper, _ := os.Open("tests/fixtures/lastfm.artist.page.html")
+			httpClient.Res = http.Response{Body: fScraper, StatusCode: 200}
+
+			images, err := agent.GetArtistImages(ctx, "123", "U2", "")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(images).To(HaveLen(1))
+			Expect(images[0].URL).To(Equal("https://lastfm.freetls.fastly.net/i/u/ar0/818148bf682d429dc21b59a73ef6f68e.png"))
+		})
+
+		It("returns empty list if image is the ignored default image", func() {
+			fApi, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+			apiClient.Res = http.Response{Body: fApi, StatusCode: 200}
+
+			fScraper, _ := os.Open("tests/fixtures/lastfm.artist.page.ignored.html")
+			httpClient.Res = http.Response{Body: fScraper, StatusCode: 200}
+
+			images, err := agent.GetArtistImages(ctx, "123", "U2", "")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(images).To(BeEmpty())
+		})
+
+		It("returns empty list if page has no meta tags", func() {
+			fApi, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+			apiClient.Res = http.Response{Body: fApi, StatusCode: 200}
+
+			fScraper, _ := os.Open("tests/fixtures/lastfm.artist.page.no_meta.html")
+			httpClient.Res = http.Response{Body: fScraper, StatusCode: 200}
+
+			images, err := agent.GetArtistImages(ctx, "123", "U2", "")
+			Expect(err).ToNot(HaveOccurred())
+			Expect(images).To(BeEmpty())
+		})
+
+		It("returns error if API call fails", func() {
+			apiClient.Err = errors.New("api error")
+			_, err := agent.GetArtistImages(ctx, "123", "U2", "")
+			Expect(err).To(HaveOccurred())
+			Expect(err.Error()).To(ContainSubstring("get artist info"))
+		})
+
+		It("returns error if scraper call fails", func() {
+			fApi, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+			apiClient.Res = http.Response{Body: fApi, StatusCode: 200}
+
+			httpClient.Err = errors.New("scraper error")
+			_, err := agent.GetArtistImages(ctx, "123", "U2", "")
+			Expect(err).To(HaveOccurred())
+			Expect(err.Error()).To(ContainSubstring("get artist url"))
+		})
+	})
+})

core/agents/lastfm/auth_router.go

@@ -0,0 +1,132 @@
+package lastfm
+
+import (
+	"bytes"
+	"context"
+	_ "embed"
+	"errors"
+	"net/http"
+	"time"
+
+	"github.com/deluan/rest"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/consts"
+	"github.com/navidrome/navidrome/core/agents"
+	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/model/request"
+	"github.com/navidrome/navidrome/server"
+	"github.com/navidrome/navidrome/utils/req"
+)
+
+//go:embed token_received.html
+var tokenReceivedPage []byte
+
+type Router struct {
+	http.Handler
+	ds          model.DataStore
+	sessionKeys *agents.SessionKeys
+	client      *client
+	apiKey      string
+	secret      string
+}
+
+func NewRouter(ds model.DataStore) *Router {
+	r := &Router{
+		ds:          ds,
+		apiKey:      conf.Server.LastFM.ApiKey,
+		secret:      conf.Server.LastFM.Secret,
+		sessionKeys: &agents.SessionKeys{DataStore: ds, KeyName: sessionKeyProperty},
+	}
+	r.Handler = r.routes()
+	hc := &http.Client{
+		Timeout: consts.DefaultHttpClientTimeOut,
+	}
+	r.client = newClient(r.apiKey, r.secret, "en", hc)
+	return r
+}
+
+func (s *Router) routes() http.Handler {
+	r := chi.NewRouter()
+
+	r.Group(func(r chi.Router) {
+		r.Use(server.Authenticator(s.ds))
+		r.Use(server.JWTRefresher)
+
+		r.Get("/link", s.getLinkStatus)
+		r.Delete("/link", s.unlink)
+	})
+
+	r.Get("/link/callback", s.callback)
+
+	return r
+}
+
+func (s *Router) getLinkStatus(w http.ResponseWriter, r *http.Request) {
+	resp := map[string]interface{}{
+		"apiKey": s.apiKey,
+	}
+	u, _ := request.UserFrom(r.Context())
+	key, err := s.sessionKeys.Get(r.Context(), u.ID)
+	if err != nil && !errors.Is(err, model.ErrNotFound) {
+		resp["error"] = err
+		resp["status"] = false
+		_ = rest.RespondWithJSON(w, http.StatusInternalServerError, resp)
+		return
+	}
+	resp["status"] = key != ""
+	_ = rest.RespondWithJSON(w, http.StatusOK, resp)
+}
+
+func (s *Router) unlink(w http.ResponseWriter, r *http.Request) {
+	u, _ := request.UserFrom(r.Context())
+	err := s.sessionKeys.Delete(r.Context(), u.ID)
+	if err != nil {
+		_ = rest.RespondWithError(w, http.StatusInternalServerError, err.Error())
+	} else {
+		_ = rest.RespondWithJSON(w, http.StatusOK, map[string]string{})
+	}
+}
+
+func (s *Router) callback(w http.ResponseWriter, r *http.Request) {
+	p := req.Params(r)
+	token, err := p.String("token")
+	if err != nil {
+		_ = rest.RespondWithError(w, http.StatusBadRequest, "token not received")
+		return
+	}
+	uid, err := p.String("uid")
+	if err != nil {
+		_ = rest.RespondWithError(w, http.StatusBadRequest, "uid not received")
+		return
+	}
+
+	// Need to add user to context, as this is a non-authenticated endpoint, so it does not
+	// automatically contain any user info
+	ctx := request.WithUser(r.Context(), model.User{ID: uid})
+	err = s.fetchSessionKey(ctx, uid, token)
+	if err != nil {
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.WriteHeader(http.StatusBadRequest)
+		_, _ = w.Write([]byte("An error occurred while authorizing with Last.fm. \n\nRequest ID: " + middleware.GetReqID(ctx)))
+		return
+	}
+
+	http.ServeContent(w, r, "response", time.Now(), bytes.NewReader(tokenReceivedPage))
+}
+
+func (s *Router) fetchSessionKey(ctx context.Context, uid, token string) error {
+	sessionKey, err := s.client.getSession(ctx, token)
+	if err != nil {
+		log.Error(ctx, "Could not fetch LastFM session key", "userId", uid, "token", token,
+			"requestId", middleware.GetReqID(ctx), err)
+		return err
+	}
+	err = s.sessionKeys.Put(ctx, uid, sessionKey)
+	if err != nil {
+		log.Error("Could not save LastFM session key", "userId", uid, "requestId", middleware.GetReqID(ctx), err)
+	}
+	return err
+}

core/agents/lastfm/client.go

@@ -0,0 +1,233 @@
+package lastfm
+
+import (
+	"context"
+	"crypto/md5"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"slices"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/navidrome/navidrome/log"
+)
+
+const (
+	apiBaseUrl = "https://ws.audioscrobbler.com/2.0/"
+)
+
+type lastFMError struct {
+	Code    int
+	Message string
+}
+
+func (e *lastFMError) Error() string {
+	return fmt.Sprintf("last.fm error(%d): %s", e.Code, e.Message)
+}
+
+type httpDoer interface {
+	Do(req *http.Request) (*http.Response, error)
+}
+
+func newClient(apiKey string, secret string, lang string, hc httpDoer) *client {
+	return &client{apiKey, secret, lang, hc}
+}
+
+type client struct {
+	apiKey string
+	secret string
+	lang   string
+	hc     httpDoer
+}
+
+func (c *client) albumGetInfo(ctx context.Context, name string, artist string, mbid string) (*Album, error) {
+	params := url.Values{}
+	params.Add("method", "album.getInfo")
+	params.Add("album", name)
+	params.Add("artist", artist)
+	params.Add("mbid", mbid)
+	params.Add("lang", c.lang)
+	response, err := c.makeRequest(ctx, http.MethodGet, params, false)
+	if err != nil {
+		return nil, err
+	}
+	return &response.Album, nil
+}
+
+func (c *client) artistGetInfo(ctx context.Context, name string) (*Artist, error) {
+	params := url.Values{}
+	params.Add("method", "artist.getInfo")
+	params.Add("artist", name)
+	params.Add("lang", c.lang)
+	response, err := c.makeRequest(ctx, http.MethodGet, params, false)
+	if err != nil {
+		return nil, err
+	}
+	return &response.Artist, nil
+}
+
+func (c *client) artistGetSimilar(ctx context.Context, name string, limit int) (*SimilarArtists, error) {
+	params := url.Values{}
+	params.Add("method", "artist.getSimilar")
+	params.Add("artist", name)
+	params.Add("limit", strconv.Itoa(limit))
+	response, err := c.makeRequest(ctx, http.MethodGet, params, false)
+	if err != nil {
+		return nil, err
+	}
+	return &response.SimilarArtists, nil
+}
+
+func (c *client) artistGetTopTracks(ctx context.Context, name string, limit int) (*TopTracks, error) {
+	params := url.Values{}
+	params.Add("method", "artist.getTopTracks")
+	params.Add("artist", name)
+	params.Add("limit", strconv.Itoa(limit))
+	response, err := c.makeRequest(ctx, http.MethodGet, params, false)
+	if err != nil {
+		return nil, err
+	}
+	return &response.TopTracks, nil
+}
+
+func (c *client) GetToken(ctx context.Context) (string, error) {
+	params := url.Values{}
+	params.Add("method", "auth.getToken")
+	c.sign(params)
+	response, err := c.makeRequest(ctx, http.MethodGet, params, true)
+	if err != nil {
+		return "", err
+	}
+	return response.Token, nil
+}
+
+func (c *client) getSession(ctx context.Context, token string) (string, error) {
+	params := url.Values{}
+	params.Add("method", "auth.getSession")
+	params.Add("token", token)
+	response, err := c.makeRequest(ctx, http.MethodGet, params, true)
+	if err != nil {
+		return "", err
+	}
+	return response.Session.Key, nil
+}
+
+type ScrobbleInfo struct {
+	artist      string
+	track       string
+	album       string
+	trackNumber int
+	mbid        string
+	duration    int
+	albumArtist string
+	timestamp   time.Time
+}
+
+func (c *client) updateNowPlaying(ctx context.Context, sessionKey string, info ScrobbleInfo) error {
+	params := url.Values{}
+	params.Add("method", "track.updateNowPlaying")
+	params.Add("artist", info.artist)
+	params.Add("track", info.track)
+	params.Add("album", info.album)
+	params.Add("trackNumber", strconv.Itoa(info.trackNumber))
+	params.Add("mbid", info.mbid)
+	params.Add("duration", strconv.Itoa(info.duration))
+	params.Add("albumArtist", info.albumArtist)
+	params.Add("sk", sessionKey)
+	resp, err := c.makeRequest(ctx, http.MethodPost, params, true)
+	if err != nil {
+		return err
+	}
+	if resp.NowPlaying.IgnoredMessage.Code != "0" {
+		log.Warn(ctx, "LastFM: NowPlaying was ignored", "code", resp.NowPlaying.IgnoredMessage.Code,
+			"text", resp.NowPlaying.IgnoredMessage.Text)
+	}
+	return nil
+}
+
+func (c *client) scrobble(ctx context.Context, sessionKey string, info ScrobbleInfo) error {
+	params := url.Values{}
+	params.Add("method", "track.scrobble")
+	params.Add("timestamp", strconv.FormatInt(info.timestamp.Unix(), 10))
+	params.Add("artist", info.artist)
+	params.Add("track", info.track)
+	params.Add("album", info.album)
+	params.Add("trackNumber", strconv.Itoa(info.trackNumber))
+	params.Add("mbid", info.mbid)
+	params.Add("duration", strconv.Itoa(info.duration))
+	params.Add("albumArtist", info.albumArtist)
+	params.Add("sk", sessionKey)
+	resp, err := c.makeRequest(ctx, http.MethodPost, params, true)
+	if err != nil {
+		return err
+	}
+	if resp.Scrobbles.Scrobble.IgnoredMessage.Code != "0" {
+		log.Warn(ctx, "LastFM: scrobble was ignored", "code", resp.Scrobbles.Scrobble.IgnoredMessage.Code,
+			"text", resp.Scrobbles.Scrobble.IgnoredMessage.Text, "info", info)
+	}
+	if resp.Scrobbles.Attr.Accepted != 1 {
+		log.Warn(ctx, "LastFM: scrobble was not accepted", "code", resp.Scrobbles.Scrobble.IgnoredMessage.Code,
+			"text", resp.Scrobbles.Scrobble.IgnoredMessage.Text, "info", info)
+	}
+	return nil
+}
+
+func (c *client) makeRequest(ctx context.Context, method string, params url.Values, signed bool) (*Response, error) {
+	params.Add("format", "json")
+	params.Add("api_key", c.apiKey)
+
+	if signed {
+		c.sign(params)
+	}
+
+	req, _ := http.NewRequestWithContext(ctx, method, apiBaseUrl, nil)
+	req.URL.RawQuery = params.Encode()
+
+	log.Trace(ctx, fmt.Sprintf("Sending Last.fm %s request", req.Method), "url", req.URL)
+	resp, err := c.hc.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	defer resp.Body.Close()
+	decoder := json.NewDecoder(resp.Body)
+
+	var response Response
+	jsonErr := decoder.Decode(&response)
+	if resp.StatusCode != 200 && jsonErr != nil {
+		return nil, fmt.Errorf("last.fm http status: (%d)", resp.StatusCode)
+	}
+	if jsonErr != nil {
+		return nil, jsonErr
+	}
+	if response.Error != 0 {
+		return &response, &lastFMError{Code: response.Error, Message: response.Message}
+	}
+
+	return &response, nil
+}
+
+func (c *client) sign(params url.Values) {
+	// the parameters must be in order before hashing
+	keys := make([]string, 0, len(params))
+	for k := range params {
+		if slices.Contains([]string{"format", "callback"}, k) {
+			continue
+		}
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	msg := strings.Builder{}
+	for _, k := range keys {
+		msg.WriteString(k)
+		msg.WriteString(params[k][0])
+	}
+	msg.WriteString(c.secret)
+	hash := md5.Sum([]byte(msg.String()))
+	params.Add("api_sig", hex.EncodeToString(hash[:]))
+}

core/agents/lastfm/client_test.go

@@ -0,0 +1,173 @@
+package lastfm
+
+import (
+	"bytes"
+	"context"
+	"crypto/md5"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("client", func() {
+	var httpClient *tests.FakeHttpClient
+	var client *client
+
+	BeforeEach(func() {
+		httpClient = &tests.FakeHttpClient{}
+		client = newClient("API_KEY", "SECRET", "pt", httpClient)
+	})
+
+	Describe("albumGetInfo", func() {
+		It("returns an album on successful response", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.album.getinfo.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+
+			album, err := client.albumGetInfo(context.Background(), "Believe", "U2", "mbid-1234")
+			Expect(err).To(BeNil())
+			Expect(album.Name).To(Equal("Believe"))
+			Expect(httpClient.SavedRequest.URL.String()).To(Equal(apiBaseUrl + "?album=Believe&api_key=API_KEY&artist=U2&format=json&lang=pt&mbid=mbid-1234&method=album.getInfo"))
+		})
+	})
+
+	Describe("artistGetInfo", func() {
+		It("returns an artist for a successful response", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.artist.getinfo.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+
+			artist, err := client.artistGetInfo(context.Background(), "U2")
+			Expect(err).To(BeNil())
+			Expect(artist.Name).To(Equal("U2"))
+			Expect(httpClient.SavedRequest.URL.String()).To(Equal(apiBaseUrl + "?api_key=API_KEY&artist=U2&format=json&lang=pt&method=artist.getInfo"))
+		})
+
+		It("fails if Last.fm returns an http status != 200", func() {
+			httpClient.Res = http.Response{
+				Body:       io.NopCloser(bytes.NewBufferString(`Internal Server Error`)),
+				StatusCode: 500,
+			}
+
+			_, err := client.artistGetInfo(context.Background(), "U2")
+			Expect(err).To(MatchError("last.fm http status: (500)"))
+		})
+
+		It("fails if Last.fm returns an http status != 200", func() {
+			httpClient.Res = http.Response{
+				Body:       io.NopCloser(bytes.NewBufferString(`{"error":3,"message":"Invalid Method - No method with that name in this package"}`)),
+				StatusCode: 400,
+			}
+
+			_, err := client.artistGetInfo(context.Background(), "U2")
+			Expect(err).To(MatchError(&lastFMError{Code: 3, Message: "Invalid Method - No method with that name in this package"}))
+		})
+
+		It("fails if Last.fm returns an error", func() {
+			httpClient.Res = http.Response{
+				Body:       io.NopCloser(bytes.NewBufferString(`{"error":6,"message":"The artist you supplied could not be found"}`)),
+				StatusCode: 200,
+			}
+
+			_, err := client.artistGetInfo(context.Background(), "U2")
+			Expect(err).To(MatchError(&lastFMError{Code: 6, Message: "The artist you supplied could not be found"}))
+		})
+
+		It("fails if HttpClient.Do() returns error", func() {
+			httpClient.Err = errors.New("generic error")
+
+			_, err := client.artistGetInfo(context.Background(), "U2")
+			Expect(err).To(MatchError("generic error"))
+		})
+
+		It("fails if returned body is not a valid JSON", func() {
+			httpClient.Res = http.Response{
+				Body:       io.NopCloser(bytes.NewBufferString(`<xml>NOT_VALID_JSON</xml>`)),
+				StatusCode: 200,
+			}
+
+			_, err := client.artistGetInfo(context.Background(), "U2")
+			Expect(err).To(MatchError("invalid character '<' looking for beginning of value"))
+		})
+
+	})
+
+	Describe("artistGetSimilar", func() {
+		It("returns an artist for a successful response", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.artist.getsimilar.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+
+			similar, err := client.artistGetSimilar(context.Background(), "U2", 2)
+			Expect(err).To(BeNil())
+			Expect(len(similar.Artists)).To(Equal(2))
+			Expect(httpClient.SavedRequest.URL.String()).To(Equal(apiBaseUrl + "?api_key=API_KEY&artist=U2&format=json&limit=2&method=artist.getSimilar"))
+		})
+	})
+
+	Describe("artistGetTopTracks", func() {
+		It("returns top tracks for a successful response", func() {
+			f, _ := os.Open("tests/fixtures/lastfm.artist.gettoptracks.json")
+			httpClient.Res = http.Response{Body: f, StatusCode: 200}
+
+			top, err := client.artistGetTopTracks(context.Background(), "U2", 2)
+			Expect(err).To(BeNil())
+			Expect(len(top.Track)).To(Equal(2))
+			Expect(httpClient.SavedRequest.URL.String()).To(Equal(apiBaseUrl + "?api_key=API_KEY&artist=U2&format=json&limit=2&method=artist.getTopTracks"))
+		})
+	})
+
+	Describe("GetToken", func() {
+		It("returns a token when the request is successful", func() {
+			httpClient.Res = http.Response{
+				Body:       io.NopCloser(bytes.NewBufferString(`{"token":"TOKEN"}`)),
+				StatusCode: 200,
+			}
+
+			Expect(client.GetToken(context.Background())).To(Equal("TOKEN"))
+			queryParams := httpClient.SavedRequest.URL.Query()
+			Expect(queryParams.Get("method")).To(Equal("auth.getToken"))
+			Expect(queryParams.Get("format")).To(Equal("json"))
+			Expect(queryParams.Get("api_key")).To(Equal("API_KEY"))
+			Expect(queryParams.Get("api_sig")).ToNot(BeEmpty())
+		})
+	})
+
+	Describe("getSession", func() {
+		It("returns a session key when the request is successful", func() {
+			httpClient.Res = http.Response{
+				Body:       io.NopCloser(bytes.NewBufferString(`{"session":{"name":"Navidrome","key":"SESSION_KEY","subscriber":0}}`)),
+				StatusCode: 200,
+			}
+
+			Expect(client.getSession(context.Background(), "TOKEN")).To(Equal("SESSION_KEY"))
+			queryParams := httpClient.SavedRequest.URL.Query()
+			Expect(queryParams.Get("method")).To(Equal("auth.getSession"))
+			Expect(queryParams.Get("format")).To(Equal("json"))
+			Expect(queryParams.Get("token")).To(Equal("TOKEN"))
+			Expect(queryParams.Get("api_key")).To(Equal("API_KEY"))
+			Expect(queryParams.Get("api_sig")).ToNot(BeEmpty())
+		})
+	})
+
+	Describe("sign", func() {
+		It("adds an api_sig param with the signature", func() {
+			params := url.Values{}
+			params.Add("d", "444")
+			params.Add("callback", "https://myserver.com")
+			params.Add("a", "111")
+			params.Add("format", "json")
+			params.Add("c", "333")
+			params.Add("b", "222")
+			client.sign(params)
+			Expect(params).To(HaveKey("api_sig"))
+			sig := params.Get("api_sig")
+			expected := fmt.Sprintf("%x", md5.Sum([]byte("a111b222c333d444SECRET")))
+			Expect(sig).To(Equal(expected))
+		})
+	})
+})

core/agents/lastfm/lastfm_suite_test.go

@@ -0,0 +1,17 @@
+package lastfm
+
+import (
+	"testing"
+
+	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestLastFM(t *testing.T) {
+	tests.Init(t, false)
+	log.SetLevel(log.LevelFatal)
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "LastFM Test Suite")
+}

core/agents/lastfm/responses.go

@@ -0,0 +1,119 @@
+package lastfm
+
+type Response struct {
+	Artist         Artist         `json:"artist"`
+	SimilarArtists SimilarArtists `json:"similarartists"`
+	TopTracks      TopTracks      `json:"toptracks"`
+	Album          Album          `json:"album"`
+	Error          int            `json:"error"`
+	Message        string         `json:"message"`
+	Token          string         `json:"token"`
+	Session        Session        `json:"session"`
+	NowPlaying     NowPlaying     `json:"nowplaying"`
+	Scrobbles      Scrobbles      `json:"scrobbles"`
+}
+
+type Album struct {
+	Name        string          `json:"name"`
+	MBID        string          `json:"mbid"`
+	URL         string          `json:"url"`
+	Image       []ExternalImage `json:"image"`
+	Description Description     `json:"wiki"`
+}
+
+type Artist struct {
+	Name  string          `json:"name"`
+	MBID  string          `json:"mbid"`
+	URL   string          `json:"url"`
+	Image []ExternalImage `json:"image"`
+	Bio   Description     `json:"bio"`
+}
+
+type SimilarArtists struct {
+	Artists []Artist `json:"artist"`
+	Attr    Attr     `json:"@attr"`
+}
+
+type Attr struct {
+	Artist string `json:"artist"`
+}
+
+type ExternalImage struct {
+	URL  string `json:"#text"`
+	Size string `json:"size"`
+}
+
+type Description struct {
+	Published string `json:"published"`
+	Summary   string `json:"summary"`
+	Content   string `json:"content"`
+}
+
+type Track struct {
+	Name string `json:"name"`
+	MBID string `json:"mbid"`
+}
+
+type TopTracks struct {
+	Track []Track `json:"track"`
+	Attr  Attr    `json:"@attr"`
+}
+
+type Session struct {
+	Name       string `json:"name"`
+	Key        string `json:"key"`
+	Subscriber int    `json:"subscriber"`
+}
+
+type NowPlaying struct {
+	Artist struct {
+		Corrected string `json:"corrected"`
+		Text      string `json:"#text"`
+	} `json:"artist"`
+	IgnoredMessage struct {
+		Code string `json:"code"`
+		Text string `json:"#text"`
+	} `json:"ignoredMessage"`
+	Album struct {
+		Corrected string `json:"corrected"`
+		Text      string `json:"#text"`
+	} `json:"album"`
+	AlbumArtist struct {
+		Corrected string `json:"corrected"`
+		Text      string `json:"#text"`
+	} `json:"albumArtist"`
+	Track struct {
+		Corrected string `json:"corrected"`
+		Text      string `json:"#text"`
+	} `json:"track"`
+}
+
+type Scrobbles struct {
+	Attr struct {
+		Accepted int `json:"accepted"`
+		Ignored  int `json:"ignored"`
+	} `json:"@attr"`
+	Scrobble struct {
+		Artist struct {
+			Corrected string `json:"corrected"`
+			Text      string `json:"#text"`
+		} `json:"artist"`
+		IgnoredMessage struct {
+			Code string `json:"code"`
+			Text string `json:"#text"`
+		} `json:"ignoredMessage"`
+		AlbumArtist struct {
+			Corrected string `json:"corrected"`
+			Text      string `json:"#text"`
+		} `json:"albumArtist"`
+		Timestamp string `json:"timestamp"`
+		Album     struct {
+			Corrected string `json:"corrected"`
+			Text      string `json:"#text"`
+		} `json:"album"`
+		Track struct {
+			Corrected string `json:"corrected"`
+			Text      string `json:"#text"`
+		} `json:"track"`
+	} `json:"scrobble"`
+}

core/agents/lastfm/responses_test.go

@@ -0,0 +1,65 @@
+package lastfm
+
+import (
+	"encoding/json"
+	"os"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("LastFM responses", func() {
+	Describe("Artist", func() {
+		It("parses the response correctly", func() {
+			var resp Response
+			body, _ := os.ReadFile("tests/fixtures/lastfm.artist.getinfo.json")
+			err := json.Unmarshal(body, &resp)
+			Expect(err).To(BeNil())
+
+			Expect(resp.Artist.Name).To(Equal("U2"))
+			Expect(resp.Artist.MBID).To(Equal("a3cb23fc-acd3-4ce0-8f36-1e5aa6a18432"))
+			Expect(resp.Artist.URL).To(Equal("https://www.last.fm/music/U2"))
+			Expect(resp.Artist.Bio.Summary).To(ContainSubstring("U2 é uma das mais importantes bandas de rock de todos os tempos"))
+		})
+	})
+
+	Describe("SimilarArtists", func() {
+		It("parses the response correctly", func() {
+			var resp Response
+			body, _ := os.ReadFile("tests/fixtures/lastfm.artist.getsimilar.json")
+			err := json.Unmarshal(body, &resp)
+			Expect(err).To(BeNil())
+
+			Expect(resp.SimilarArtists.Artists).To(HaveLen(2))
+			Expect(resp.SimilarArtists.Artists[0].Name).To(Equal("Passengers"))
+			Expect(resp.SimilarArtists.Artists[1].Name).To(Equal("INXS"))
+		})
+	})
+
+	Describe("TopTracks", func() {
+		It("parses the response correctly", func() {
+			var resp Response
+			body, _ := os.ReadFile("tests/fixtures/lastfm.artist.gettoptracks.json")
+			err := json.Unmarshal(body, &resp)
+			Expect(err).To(BeNil())
+
+			Expect(resp.TopTracks.Track).To(HaveLen(2))
+			Expect(resp.TopTracks.Track[0].Name).To(Equal("Beautiful Day"))
+			Expect(resp.TopTracks.Track[0].MBID).To(Equal("f7f264d0-a89b-4682-9cd7-a4e7c37637af"))
+			Expect(resp.TopTracks.Track[1].Name).To(Equal("With or Without You"))
+			Expect(resp.TopTracks.Track[1].MBID).To(Equal("6b9a509f-6907-4a6e-9345-2f12da09ba4b"))
+		})
+	})
+
+	Describe("Error", func() {
+		It("parses the error response correctly", func() {
+			var error Response
+			body := []byte(`{"error":3,"message":"Invalid Method - No method with that name in this package"}`)
+			err := json.Unmarshal(body, &error)
+			Expect(err).To(BeNil())
+
+			Expect(error.Error).To(Equal(3))
+			Expect(error.Message).To(Equal("Invalid Method - No method with that name in this package"))
+		})
+	})
+})

core/agents/lastfm/token_received.html

@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8" />
+    <title>Account Linking Success</title>
+  </head>
+  <body>
+    <h2 id="msg"></h2>
+    <script>
+      setTimeout("document.getElementById('msg').innerHTML = 'Success! Your account is linked to Last.fm. You can close this tab now.';",2000)
+      document.addEventListener("DOMContentLoaded", () => {
+        window.close();
+      });
+    </script>
+  </body>
+</html>