Use ytdlp to get the correct playlist thumbnail

Author: chkuendig

pkg/builder/builder.go

@@ -13,10 +13,10 @@ type Builder interface {
 	Build(ctx context.Context, cfg *feed.Config) (*model.Feed, error)
 }
 
-func New(ctx context.Context, provider model.Provider, key string) (Builder, error) {
+func New(ctx context.Context, provider model.Provider, key string, downloader Downloader) (Builder, error) {
 	switch provider {
 	case model.ProviderYoutube:
-		return NewYouTubeBuilder(key)
+		return NewYouTubeBuilder(key, downloader)
 	case model.ProviderVimeo:
 		return NewVimeoBuilder(ctx, key)
 	case model.ProviderSoundcloud:

pkg/builder/youtube.go

@@ -16,7 +16,11 @@ import (
 	"google.golang.org/api/youtube/v3"
 
 	"github.com/mxpv/podsync/pkg/model"
+	"github.com/mxpv/podsync/pkg/ytdl"
 )
+type Downloader interface {
+	PlaylistMetadata(ctx context.Context, url string) (metadata ytdl.PlaylistMetadata, err error) 
+}
 
 const (
 	maxYoutubeResults       = 50
@@ -35,6 +39,7 @@ func (key apiKey) Get() (string, string) {
 type YouTubeBuilder struct {
 	client *youtube.Service
 	key    apiKey
+	downloader Downloader
 }
 
 // Cost: 5 units (call method: 1, snippet: 2, contentDetails: 2)
@@ -225,8 +230,17 @@ func (yt *YouTubeBuilder) queryFeed(ctx context.Context, feed *model.Feed, info
 		} else { // nolint:golint
 			feed.PubDate = date
 		}
-		
-		thumbnails = playlist.Snippet.Thumbnails
+		metadata, err := yt.downloader.PlaylistMetadata(ctx, feed.ItemURL)
+		if err != nil {
+			return errors.Wrapf(err, "failed to get playlist metadata for %s", feed.ItemURL)
+		}
+		log.Infof("Playlist metadata: %v", metadata)
+		if(len(metadata.Thumbnails) > 0) {
+			// best qualtiy thumbnail is the last one
+			feed.CoverArt = metadata.Thumbnails[len(metadata.Thumbnails)-1].Url
+		} else {
+			thumbnails = playlist.Snippet.Thumbnails
+		}
 
 	default:
 		return errors.New("unsupported link format")
@@ -235,9 +249,9 @@ func (yt *YouTubeBuilder) queryFeed(ctx context.Context, feed *model.Feed, info
 	if feed.Description == "" {
 		feed.Description = fmt.Sprintf("%s (%s)", feed.Title, feed.PubDate)
 	}
-
+	if feed.CoverArt == "" {
 		feed.CoverArt = yt.selectThumbnail(thumbnails, feed.CoverArtQuality, "")
-	
+	}
 	return nil
 }
 
@@ -457,7 +471,7 @@ func (yt *YouTubeBuilder) Build(ctx context.Context, cfg *feed.Config) (*model.F
 	return _feed, nil
 }
 
-func NewYouTubeBuilder(key string) (*YouTubeBuilder, error) {
+func NewYouTubeBuilder(key string, ytdlp Downloader) (*YouTubeBuilder, error) {
 	if key == "" {
 		return nil, errors.New("empty YouTube API key")
 	}
@@ -467,5 +481,5 @@ func NewYouTubeBuilder(key string) (*YouTubeBuilder, error) {
 		return nil, errors.Wrap(err, "failed to create youtube client")
 	}
 
-	return &YouTubeBuilder{client: yt, key: apiKey(key)}, nil
+	return &YouTubeBuilder{client: yt, key: apiKey(key), downloader:ytdlp}, nil
 }

pkg/ytdl/ytdl.go

@@ -1,6 +1,7 @@
 package ytdl
 
 import (
+    "encoding/json"
 	"context"
 	"fmt"
 	"io"
@@ -24,6 +25,26 @@ const (
 	UpdatePeriod           = 24 * time.Hour
 )
 
+type PlaylistMetadataThumbnail struct {
+	Id string `json:"id"`
+	Url string `json:"url"`
+	Resolution string `json:"resolution"`
+	Width int `json:"width"`
+	Height int `json:"height"`
+}
+
+type PlaylistMetadata struct {
+  Id string `json:"id"`
+  Title string `json:"title"`
+  Description string `json:"description"`
+  Thumbnails []PlaylistMetadataThumbnail `json:"thumbnails"`
+  Channel string `json:"channel"`
+  ChannelId string `json:"channel_id"`
+  ChannelUrl string `json:"channel_url"`
+  WebpageUrl string `json:"webpage_url"`
+
+}
+
 var (
 	ErrTooManyRequests = errors.New(http.StatusText(http.StatusTooManyRequests))
 )
@@ -156,6 +177,36 @@ func (dl *YoutubeDl) Update(ctx context.Context) error {
 	return nil
 }
 
+
+func (dl *YoutubeDl) PlaylistMetadata(ctx context.Context, url string) (metadata PlaylistMetadata, err error) {
+	log.Info("getting playlist metadata for: ", url)
+	args := []string{
+		"--playlist-items", "0",
+		"-J", // JSON output
+		"-q", // quiet mode
+		"--no-warnings", // suppress warnings
+		url,
+	}
+	dl.updateLock.Lock()
+	defer dl.updateLock.Unlock()
+	output, err := dl.exec(ctx, args...)
+	if err != nil {
+		log.WithError(err).Errorf("youtube-dl error: %s", url)
+
+		// YouTube might block host with HTTP Error 429: Too Many Requests
+		if strings.Contains(output, "HTTP Error 429") {
+			return PlaylistMetadata{}, ErrTooManyRequests
+		}
+
+		log.Error(output)
+		return PlaylistMetadata{}, errors.New(output)
+	}
+
+	var playlistMetadata PlaylistMetadata
+	json.Unmarshal([]byte(output), &playlistMetadata)
+	return playlistMetadata, nil
+}
+
 func (dl *YoutubeDl) Download(ctx context.Context, feedConfig *feed.Config, episode *model.Episode) (r io.ReadCloser, err error) {
 	tmpDir, err := os.MkdirTemp("", "podsync-")
 	if err != nil {

services/update/updater.go

@@ -23,6 +23,7 @@ import (
 
 type Downloader interface {
 	Download(ctx context.Context, feedConfig *feed.Config, episode *model.Episode) (io.ReadCloser, error)
+	PlaylistMetadata(ctx context.Context, url string) (metadata ytdl.PlaylistMetadata, err error) 
 }
 
 type TokenList []string