refactor scrobblers (#383)

- no need to explicitly pass api key - move packages up a level - catch more errors by extended scrobbler interface with IsUserAuthenticated - move interface to server - delete scrobbber package, clients implicitly satisfy Scrobble this also helps with gonic-lastfm-sync
2023-09-27 01:13:00 +01:00
parent 32064d0279
commit f119659acf
27 changed files with 1100 additions and 1144 deletions
--- a/lastfm/client.go
+++ b/lastfm/client.go
@@ -0,0 +1,312 @@
+package lastfm
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/andybalholm/cascadia"
+	"github.com/google/uuid"
+	"go.senan.xyz/gonic/db"
+	"golang.org/x/net/html"
+)
+
+var (
+	ErrLastFM        = errors.New("last.fm error")
+	ErrNoUserSession = errors.New("no lastfm user session present")
+)
+
+type KeySecretFunc func() (apiKey, secret string, err error)
+
+type Client struct {
+	httpClient *http.Client
+	keySecret  KeySecretFunc
+}
+
+func NewClient(keySecret KeySecretFunc) *Client {
+	return NewClientCustom(http.DefaultClient, keySecret)
+}
+
+func NewClientCustom(httpClient *http.Client, keySecret KeySecretFunc) *Client {
+	return &Client{httpClient: httpClient, keySecret: keySecret}
+}
+
+const (
+	BaseURL = "https://ws.audioscrobbler.com/2.0/"
+)
+
+func (c *Client) ArtistGetInfo(artistName string) (Artist, error) {
+	apiKey, _, err := c.keySecret()
+	if err != nil {
+		return Artist{}, fmt.Errorf("get key and secret: %w", err)
+	}
+
+	params := url.Values{}
+	params.Add("method", "artist.getInfo")
+	params.Add("api_key", apiKey)
+	params.Add("artist", artistName)
+
+	resp, err := c.makeRequest(http.MethodGet, params)
+	if err != nil {
+		return Artist{}, fmt.Errorf("make request: %w", err)
+	}
+	return resp.Artist, nil
+}
+
+func (c *Client) ArtistGetTopTracks(artistName string) (TopTracks, error) {
+	apiKey, _, err := c.keySecret()
+	if err != nil {
+		return TopTracks{}, fmt.Errorf("get key and secret: %w", err)
+	}
+
+	params := url.Values{}
+	params.Add("method", "artist.getTopTracks")
+	params.Add("api_key", apiKey)
+	params.Add("artist", artistName)
+
+	resp, err := c.makeRequest(http.MethodGet, params)
+	if err != nil {
+		return TopTracks{}, fmt.Errorf("make request: %w", err)
+	}
+	return resp.TopTracks, nil
+}
+
+func (c *Client) TrackGetSimilarTracks(artistName, trackName string) (SimilarTracks, error) {
+	apiKey, _, err := c.keySecret()
+	if err != nil {
+		return SimilarTracks{}, fmt.Errorf("get key and secret: %w", err)
+	}
+
+	params := url.Values{}
+	params.Add("method", "track.getSimilar")
+	params.Add("api_key", apiKey)
+	params.Add("track", trackName)
+	params.Add("artist", artistName)
+
+	resp, err := c.makeRequest(http.MethodGet, params)
+	if err != nil {
+		return SimilarTracks{}, fmt.Errorf("make request: %w", err)
+	}
+	return resp.SimilarTracks, nil
+}
+
+func (c *Client) ArtistGetSimilar(artistName string) (SimilarArtists, error) {
+	apiKey, _, err := c.keySecret()
+	if err != nil {
+		return SimilarArtists{}, fmt.Errorf("get key and secret: %w", err)
+	}
+
+	params := url.Values{}
+	params.Add("method", "artist.getSimilar")
+	params.Add("api_key", apiKey)
+	params.Add("artist", artistName)
+
+	resp, err := c.makeRequest(http.MethodGet, params)
+	if err != nil {
+		return SimilarArtists{}, fmt.Errorf("making similar artists GET:  %w", err)
+	}
+	return resp.SimilarArtists, nil
+}
+
+func (c *Client) UserGetLovedTracks(userName string) (LovedTracks, error) {
+	apiKey, _, err := c.keySecret()
+	if err != nil {
+		return LovedTracks{}, fmt.Errorf("get key and secret: %w", err)
+	}
+
+	params := url.Values{}
+	params.Add("method", "user.getLovedTracks")
+	params.Add("api_key", apiKey)
+	params.Add("user", userName)
+	params.Add("limit", "1000") // TODO: paginate
+
+	resp, err := c.makeRequest(http.MethodGet, params)
+	if err != nil {
+		return LovedTracks{}, fmt.Errorf("making user get loved tracks GET:  %w", err)
+	}
+	return resp.LovedTracks, nil
+}
+
+func (c *Client) GetSession(token string) (string, error) {
+	apiKey, secret, err := c.keySecret()
+	if err != nil {
+		return "", fmt.Errorf("get key and secret: %w", err)
+	}
+
+	params := url.Values{}
+	params.Add("method", "auth.getSession")
+	params.Add("api_key", apiKey)
+	params.Add("token", token)
+	params.Add("api_sig", GetParamSignature(params, secret))
+
+	resp, err := c.makeRequest(http.MethodGet, params)
+	if err != nil {
+		return "", fmt.Errorf("make request: %w", err)
+	}
+	return resp.Session.Key, nil
+}
+
+//nolint:gochecknoglobals
+var artistOpenGraphQuery = cascadia.MustCompile(`html > head > meta[property="og:image"]`)
+
+func (c *Client) StealArtistImage(artistURL string) (string, error) {
+	resp, err := c.httpClient.Get(artistURL) //nolint:gosec
+	if err != nil {
+		return "", fmt.Errorf("get artist url: %w", err)
+	}
+	defer resp.Body.Close()
+
+	node, err := html.Parse(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("parse html: %w", err)
+	}
+
+	n := cascadia.Query(node, artistOpenGraphQuery)
+	if n == nil {
+		return "", nil
+	}
+
+	var imageURL string
+	for _, attr := range n.Attr {
+		if attr.Key == "content" {
+			imageURL = attr.Val
+			break
+		}
+	}
+
+	return imageURL, nil
+}
+
+func (c *Client) IsUserAuthenticated(user *db.User) bool {
+	return user.LastFMSession != ""
+}
+
+func (c *Client) Scrobble(user *db.User, track *db.Track, stamp time.Time, submission bool) error {
+	apiKey, secret, err := c.keySecret()
+	if err != nil {
+		return fmt.Errorf("get key and secret: %w", err)
+	}
+	if !c.IsUserAuthenticated(user) {
+		return ErrNoUserSession
+	}
+
+	if track.Album == nil || len(track.Album.Artists) == 0 {
+		return fmt.Errorf("track has no album artists")
+	}
+
+	params := url.Values{}
+	if submission {
+		params.Add("method", "track.Scrobble")
+		// last.fm wants the timestamp in seconds
+		params.Add("timestamp", strconv.Itoa(int(stamp.Unix())))
+	} else {
+		params.Add("method", "track.updateNowPlaying")
+	}
+
+	params.Add("api_key", apiKey)
+	params.Add("sk", user.LastFMSession)
+	params.Add("artist", track.TagTrackArtist)
+	params.Add("track", track.TagTitle)
+	params.Add("trackNumber", strconv.Itoa(track.TagTrackNumber))
+	params.Add("album", track.Album.TagTitle)
+	params.Add("albumArtist", strings.Join(track.Album.ArtistsStrings(), ", "))
+	params.Add("duration", strconv.Itoa(track.Length))
+
+	// make sure we provide a valid uuid, since some users may have an incorrect mbid in their tags
+	if _, err := uuid.Parse(track.TagBrainzID); err == nil {
+		params.Add("mbid", track.TagBrainzID)
+	}
+
+	params.Add("api_sig", GetParamSignature(params, secret))
+
+	_, err = c.makeRequest(http.MethodPost, params)
+	return err
+}
+
+func (c *Client) LoveTrack(user *db.User, track *db.Track) error {
+	apiKey, secret, err := c.keySecret()
+	if err != nil {
+		return fmt.Errorf("get key and secret: %w", err)
+	}
+	if !c.IsUserAuthenticated(user) {
+		return ErrNoUserSession
+	}
+
+	params := url.Values{}
+	params.Add("method", "track.love")
+	params.Add("track", track.TagTitle)
+	params.Add("artist", track.TagTrackArtist)
+	params.Add("api_key", apiKey)
+	params.Add("sk", user.LastFMSession)
+	params.Add("api_sig", GetParamSignature(params, secret))
+
+	_, err = c.makeRequest(http.MethodPost, params)
+	return err
+}
+
+func (c *Client) GetCurrentUser(user *db.User) (User, error) {
+	apiKey, secret, err := c.keySecret()
+	if err != nil {
+		return User{}, fmt.Errorf("get key and secret: %w", err)
+	}
+	if !c.IsUserAuthenticated(user) {
+		return User{}, ErrNoUserSession
+	}
+
+	params := url.Values{}
+	params.Add("method", "user.getInfo")
+	params.Add("api_key", apiKey)
+	params.Add("sk", user.LastFMSession)
+	params.Add("api_sig", GetParamSignature(params, secret))
+
+	resp, err := c.makeRequest(http.MethodGet, params)
+	if err != nil {
+		return User{}, fmt.Errorf("make request: %w", err)
+	}
+	return resp.User, nil
+}
+
+func (c *Client) makeRequest(method string, params url.Values) (LastFM, error) {
+	req, _ := http.NewRequest(method, BaseURL, nil)
+	req.URL.RawQuery = params.Encode()
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return LastFM{}, fmt.Errorf("get: %w", err)
+	}
+	defer resp.Body.Close()
+
+	var lastfm LastFM
+	if err = xml.NewDecoder(resp.Body).Decode(&lastfm); err != nil {
+		return LastFM{}, fmt.Errorf("decoding: %w", err)
+	}
+
+	if lastfm.Error.Code != 0 {
+		return LastFM{}, fmt.Errorf("%v: %w", lastfm.Error.Value, ErrLastFM)
+	}
+	return lastfm, nil
+}
+
+func GetParamSignature(params url.Values, secret string) string {
+	// the parameters must be in order before hashing
+	paramKeys := make([]string, 0, len(params))
+	for k := range params {
+		paramKeys = append(paramKeys, k)
+	}
+	sort.Strings(paramKeys)
+	toHash := ""
+	for _, k := range paramKeys {
+		toHash += k
+		toHash += params[k][0]
+	}
+	toHash += secret
+	hash := md5.Sum([]byte(toHash))
+	return hex.EncodeToString(hash[:])
+}