[spotify] Fix: Refresh-Token gets revoked when using two functions

Signed-off-by: Knut Ahlers <knut@ahlers.me>

docs/content/configuration/templating.md

@@ -467,12 +467,12 @@ Example:
 
 ```
 # Your int this hour: {{ printf "%.0f" (mulf (seededRandom (list "int" .username (now | date "2006-01-02 15") | join ":")) 100) }}%
-< Your int this hour: 72%
+< Your int this hour: 82%
 ```
 
 ### `spotifyCurrentPlaying`
 
-Retrieves the current playing track for the given channel
+Retrieves the current playing track for the given channel (returns an empty string when nothing is playing)
 
 Syntax: `spotifyCurrentPlaying <channel>`
 
@@ -487,7 +487,7 @@ Example:
 
 ### `spotifyLink`
 
-Retrieves the link for the playing track for the given channel
+Retrieves the link for the playing track for the given channel (returns an empty string when nothing is playing)
 
 Syntax: `spotifyLink <channel>`
 

internal/actors/spotify/auth.go

@@ -0,0 +1,101 @@
+package spotify
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/Luzifer/twitch-bot/v3/internal/locker"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/oauth2"
+)
+
+const expiryGrace = 10 * time.Second
+
+func getAuthorizedClient(channel, redirectURL string) (client *http.Client, err error) {
+	// In templating functions are called multiple times at once which
+	// with Spotify replacing the refresh-token on each renew would kill
+	// the stored token when multiple spotify functions are called at
+	// once. Therefore we do have this method locking itself until it
+	// has successfully made one request to the users profile and therefore
+	// renewed the token. The next request then will use the token the
+	// previous request renewed.
+	locker.LockByKey(strings.Join([]string{"spotify", "api-access", channel}, ":"))
+	defer locker.UnlockByKey(strings.Join([]string{"spotify", "api-access", channel}, ":"))
+
+	conf, err := oauthConfig(channel, redirectURL)
+	if err != nil {
+		return nil, fmt.Errorf("getting oauth config: %w", err)
+	}
+
+	var token *oauth2.Token
+	if err = db.ReadEncryptedCoreMeta(strings.Join([]string{"spotify-auth", channel}, ":"), &token); err != nil {
+		return nil, fmt.Errorf("loading oauth token: %w", err)
+	}
+
+	ts := conf.TokenSource(context.Background(), token)
+
+	if token.Expiry.After(time.Now().Add(expiryGrace)) {
+		// Token is still valid long enough, we spare the resources to do
+		// the profile fetch and directly return the client with the token
+		// as the scenario described here does not apply.
+		return oauth2.NewClient(context.Background(), ts), nil
+	}
+
+	logrus.WithField("channel", channel).Debug("refreshing spotify token")
+
+	ctx, cancel := context.WithTimeout(context.Background(), spotifyRequestTimeout)
+	defer cancel()
+
+	// We do a request to /me once to refresh the token if needed
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "https://api.spotify.com/v1/me", nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating currently-playing request: %w", err)
+	}
+
+	oauthClient := oauth2.NewClient(context.Background(), ts)
+
+	resp, err := oauthClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("executing request: %w", err)
+	}
+	defer func() {
+		if err := resp.Body.Close(); err != nil {
+			logrus.WithError(err).Error("closing Spotify response body (leaked fd)")
+		}
+	}()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("requesting user profile: %w", err)
+	}
+
+	updToken, err := ts.Token()
+	if err != nil {
+		return nil, fmt.Errorf("getting updated token: %w", err)
+	}
+
+	if err := db.StoreEncryptedCoreMeta(strings.Join([]string{"spotify-auth", channel}, ":"), updToken); err != nil {
+		logrus.WithError(err).Error("storing back Spotify auth token")
+	}
+
+	return oauthClient, nil
+}
+
+func oauthConfig(channel, redirectURL string) (conf *oauth2.Config, err error) {
+	clientID, err := getModuleConfig(actorName, channel).String("clientId")
+	if err != nil {
+		return nil, fmt.Errorf("getting clientId for channel: %w", err)
+	}
+
+	return &oauth2.Config{
+		ClientID: clientID,
+		Endpoint: oauth2.Endpoint{
+			AuthURL:  "https://accounts.spotify.com/authorize",
+			TokenURL: "https://accounts.spotify.com/api/token",
+		},
+		RedirectURL: redirectURL,
+		Scopes:      []string{"user-read-currently-playing"},
+	}, nil
+}

internal/actors/spotify/client.go

@@ -3,34 +3,25 @@ package spotify
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"strings"
 
 	"github.com/sirupsen/logrus"
-	"golang.org/x/oauth2"
 )
 
+var errNotPlaying = errors.New("nothing playing")
+
 func getCurrentTrackForChannel(channel string) (track currentPlayingTrackResponse, err error) {
 	channel = strings.TrimLeft(channel, "#")
 
-	conf, err := oauthConfig(channel, "")
+	client, err := getAuthorizedClient(channel, "")
 	if err != nil {
-		return track, fmt.Errorf("getting oauth config: %w", err)
+		return track, fmt.Errorf("retrieving authorized Spotify client: %w", err)
 	}
 
-	var token *oauth2.Token
-	if err = db.ReadEncryptedCoreMeta(strings.Join([]string{"spotify-auth", channel}, ":"), &token); err != nil {
-		return track, fmt.Errorf("loading oauth token: %w", err)
-	}
-
-	defer func() {
-		if err := db.StoreEncryptedCoreMeta(strings.Join([]string{"spotify-auth", channel}, ":"), token); err != nil {
-			logrus.WithError(err).Error("storing back Spotify auth token")
-		}
-	}()
-
 	ctx, cancel := context.WithTimeout(context.Background(), spotifyRequestTimeout)
 	defer cancel()
 
@@ -39,7 +30,7 @@ func getCurrentTrackForChannel(channel string) (track currentPlayingTrackRespons
 		return track, fmt.Errorf("creating currently-playing request: %w", err)
 	}
 
-	resp, err := conf.Client(context.Background(), token).Do(req)
+	resp, err := client.Do(req)
 	if err != nil {
 		return track, fmt.Errorf("executing request: %w", err)
 	}
@@ -58,6 +49,10 @@ func getCurrentTrackForChannel(channel string) (track currentPlayingTrackRespons
 	case http.StatusOK:
 		// This is perfect, continue below
 
+	case http.StatusNoContent:
+		// User is not playing anything
+		return track, errNotPlaying
+
 	case http.StatusUnauthorized:
 		// The token is FUBAR
 		return track, fmt.Errorf("token expired (HTTP 401 - unauthorized)")
@@ -85,6 +80,10 @@ func getCurrentTrackForChannel(channel string) (track currentPlayingTrackRespons
 func getCurrentArtistTitleForChannel(channel string) (artistTitle string, err error) {
 	track, err := getCurrentTrackForChannel(channel)
 	if err != nil {
+		if errors.Is(err, errNotPlaying) {
+			return "", nil
+		}
+
 		return "", fmt.Errorf("getting track info: %w", err)
 	}
 
@@ -102,6 +101,10 @@ func getCurrentArtistTitleForChannel(channel string) (artistTitle string, err er
 func getCurrentLinkForChannel(channel string) (link string, err error) {
 	track, err := getCurrentTrackForChannel(channel)
 	if err != nil {
+		if errors.Is(err, errNotPlaying) {
+			return "", nil
+		}
+
 		return "", fmt.Errorf("getting track info: %w", err)
 	}
 

internal/actors/spotify/http.go

@@ -70,20 +70,3 @@ func handleStartAuth(w http.ResponseWriter, r *http.Request) {
 
 	fmt.Fprintln(w, "Spotify is now authorized for this channel, you can close this page")
 }
-
-func oauthConfig(channel, redirectURL string) (conf *oauth2.Config, err error) {
-	clientID, err := getModuleConfig(actorName, channel).String("clientId")
-	if err != nil {
-		return nil, fmt.Errorf("getting clientId for channel: %w", err)
-	}
-
-	return &oauth2.Config{
-		ClientID: clientID,
-		Endpoint: oauth2.Endpoint{
-			AuthURL:  "https://accounts.spotify.com/authorize",
-			TokenURL: "https://accounts.spotify.com/api/token",
-		},
-		RedirectURL: redirectURL,
-		Scopes:      []string{"user-read-currently-playing"},
-	}, nil
-}

internal/actors/spotify/spotify.go

@@ -35,7 +35,7 @@ func Register(args plugins.RegistrationArguments) (err error) {
 		plugins.GenericTemplateFunctionGetter(getCurrentArtistTitleForChannel),
 		plugins.TemplateFuncDocumentation{
 			Name:        "spotifyCurrentPlaying",
-			Description: "Retrieves the current playing track for the given channel",
+			Description: "Retrieves the current playing track for the given channel (returns an empty string when nothing is playing)",
 			Syntax:      "spotifyCurrentPlaying <channel>",
 			Example: &plugins.TemplateFuncDocumentationExample{
 				MatchMessage:   "^!spotify",
@@ -51,7 +51,7 @@ func Register(args plugins.RegistrationArguments) (err error) {
 		plugins.GenericTemplateFunctionGetter(getCurrentLinkForChannel),
 		plugins.TemplateFuncDocumentation{
 			Name:        "spotifyLink",
-			Description: "Retrieves the link for the playing track for the given channel",
+			Description: "Retrieves the link for the playing track for the given channel (returns an empty string when nothing is playing)",
 			Syntax:      "spotifyLink <channel>",
 			Example: &plugins.TemplateFuncDocumentationExample{
 				MatchMessage:   "^!spotifylink",