Merge pull request #811 from TiA4f8R/playlists-improvements-and-yt-playlists-fixes

[YouTube] Fix the extraction of series playlists and don't return the view count as the stream count for learning playlists

extractor/src/main/java/org/schabi/newpipe/extractor/playlist/PlaylistExtractor.java

@@ -8,15 +8,14 @@ import org.schabi.newpipe.extractor.stream.StreamInfoItem;
 
 import javax.annotation.Nonnull;
 
+import static org.schabi.newpipe.extractor.utils.Utils.EMPTY_STRING;
+
 public abstract class PlaylistExtractor extends ListExtractor<StreamInfoItem> {
 
-    public PlaylistExtractor(StreamingService service, ListLinkHandler linkHandler) {
+    public PlaylistExtractor(final StreamingService service, final ListLinkHandler linkHandler) {
         super(service, linkHandler);
     }
 
-    public abstract String getThumbnailUrl() throws ParsingException;
-    public abstract String getBannerUrl() throws ParsingException;
-
     public abstract String getUploaderUrl() throws ParsingException;
     public abstract String getUploaderName() throws ParsingException;
     public abstract String getUploaderAvatarUrl() throws ParsingException;
@@ -24,8 +23,30 @@ public abstract class PlaylistExtractor extends ListExtractor<StreamInfoItem> {
 
     public abstract long getStreamCount() throws ParsingException;
 
-    @Nonnull public abstract String getSubChannelName() throws ParsingException;
+    @Nonnull
-    @Nonnull public abstract String getSubChannelUrl() throws ParsingException;
+    public String getThumbnailUrl() throws ParsingException {
-    @Nonnull public abstract String getSubChannelAvatarUrl() throws ParsingException;
+        return EMPTY_STRING;
+    }
 
+    @Nonnull
+    public String getBannerUrl() throws ParsingException {
+        // Banner can't be handled by frontend right now.
+        // Whoever is willing to implement this should also implement it in the frontend.
+        return EMPTY_STRING;
+    }
+
+    @Nonnull
+    public String getSubChannelName() throws ParsingException {
+        return EMPTY_STRING;
+    }
+
+    @Nonnull
+    public String getSubChannelUrl() throws ParsingException {
+        return EMPTY_STRING;
+    }
+
+    @Nonnull
+    public String getSubChannelAvatarUrl() throws ParsingException {
+        return EMPTY_STRING;
+    }
 }

extractor/src/main/java/org/schabi/newpipe/extractor/services/bandcamp/extractors/BandcampPlaylistExtractor.java

@@ -19,10 +19,13 @@ import org.schabi.newpipe.extractor.stream.StreamInfoItemsCollector;
 
 import javax.annotation.Nonnull;
 import java.io.IOException;
+import java.util.Objects;
 
 import static org.schabi.newpipe.extractor.services.bandcamp.extractors.BandcampExtractorHelper.getImageUrl;
 import static org.schabi.newpipe.extractor.utils.JsonUtils.getJsonData;
 import static org.schabi.newpipe.extractor.services.bandcamp.extractors.BandcampStreamExtractor.getAlbumInfoJson;
+import static org.schabi.newpipe.extractor.utils.Utils.EMPTY_STRING;
+import static org.schabi.newpipe.extractor.utils.Utils.HTTPS;
 
 public class BandcampPlaylistExtractor extends PlaylistExtractor {
 
@@ -57,33 +60,27 @@ public class BandcampPlaylistExtractor extends PlaylistExtractor {
             throw new ParsingException("JSON does not exist", e);
         }
 
-
+        if (trackInfo.isEmpty()) {
-
-        if (trackInfo.size() <= 0) {
             // Albums without trackInfo need to be purchased before they can be played
             throw new ContentNotAvailableException("Album needs to be purchased");
         }
     }
 
+    @Nonnull
     @Override
     public String getThumbnailUrl() throws ParsingException {
         if (albumJson.isNull("art_id")) {
-            return "";
+            return EMPTY_STRING;
         } else {
             return getImageUrl(albumJson.getLong("art_id"), true);
         }
     }
 
-    @Override
-    public String getBannerUrl() {
-        return "";
-    }
-
     @Override
     public String getUploaderUrl() throws ParsingException {
         final String[] parts = getUrl().split("/");
         // https: (/) (/) * .bandcamp.com (/) and leave out the rest
-        return "https://" + parts[2] + "/";
+        return HTTPS + parts[2] + "/";
     }
 
     @Override
@@ -94,9 +91,10 @@ public class BandcampPlaylistExtractor extends PlaylistExtractor {
     @Override
     public String getUploaderAvatarUrl() {
         try {
-            return document.getElementsByClass("band-photo").first().attr("src");
+            return Objects.requireNonNull(document.getElementsByClass("band-photo").first())
-        } catch (NullPointerException e) {
+                    .attr("src");
-            return "";
+        } catch (final NullPointerException e) {
+            return EMPTY_STRING;
         }
     }
 
@@ -110,24 +108,6 @@ public class BandcampPlaylistExtractor extends PlaylistExtractor {
         return trackInfo.size();
     }
 
-    @Nonnull
-    @Override
-    public String getSubChannelName() {
-        return "";
-    }
-
-    @Nonnull
-    @Override
-    public String getSubChannelUrl() {
-        return "";
-    }
-
-    @Nonnull
-    @Override
-    public String getSubChannelAvatarUrl() {
-        return "";
-    }
-
     @Nonnull
     @Override
     public InfoItemsPage<StreamInfoItem> getInitialPage() throws ExtractionException {
@@ -146,14 +126,13 @@ public class BandcampPlaylistExtractor extends PlaylistExtractor {
                 collector.commit(new BandcampPlaylistStreamInfoItemExtractor(
                         track, getUploaderUrl(), getThumbnailUrl()));
             }
-
         }
 
         return new InfoItemsPage<>(collector, null);
     }
 
     @Override
-    public InfoItemsPage<StreamInfoItem> getPage(Page page) {
+    public InfoItemsPage<StreamInfoItem> getPage(final Page page) {
         return null;
     }
 

extractor/src/main/java/org/schabi/newpipe/extractor/services/peertube/extractors/PeertubePlaylistExtractor.java

@@ -29,16 +29,12 @@ public class PeertubePlaylistExtractor extends PlaylistExtractor {
         super(service, linkHandler);
     }
 
+    @Nonnull
     @Override
     public String getThumbnailUrl() throws ParsingException {
         return getBaseUrl() + playlistInfo.getString("thumbnailPath");
     }
 
-    @Override
-    public String getBannerUrl() {
-        return null;
-    }
-
     @Override
     public String getUploaderUrl() {
         return playlistInfo.getObject("ownerAccount").getString("url");

extractor/src/main/java/org/schabi/newpipe/extractor/services/soundcloud/extractors/SoundcloudPlaylistExtractor.java

@@ -23,9 +23,9 @@ import java.util.ArrayList;
 import java.util.List;
 
 import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 
 import static org.schabi.newpipe.extractor.services.soundcloud.SoundcloudParsingHelper.SOUNDCLOUD_API_V2_URL;
+import static org.schabi.newpipe.extractor.utils.Utils.EMPTY_STRING;
 import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
 
 public class SoundcloudPlaylistExtractor extends PlaylistExtractor {
@@ -67,7 +67,7 @@ public class SoundcloudPlaylistExtractor extends PlaylistExtractor {
         return playlist.getString("title");
     }
 
-    @Nullable
+    @Nonnull
     @Override
     public String getThumbnailUrl() {
         String artworkUrl = playlist.getString("artwork_url");
@@ -80,24 +80,21 @@ public class SoundcloudPlaylistExtractor extends PlaylistExtractor {
 
                 for (final StreamInfoItem item : infoItems.getItems()) {
                     artworkUrl = item.getThumbnailUrl();
-                    if (!isNullOrEmpty(artworkUrl)) break;
+                    if (!isNullOrEmpty(artworkUrl)) {
+                        break;
+                    }
                 }
             } catch (final Exception ignored) {
             }
 
             if (artworkUrl == null) {
-                return null;
+                return EMPTY_STRING;
             }
         }
 
         return artworkUrl.replace("large.jpg", "crop.jpg");
     }
 
-    @Override
-    public String getBannerUrl() {
-        return null;
-    }
-
     @Override
     public String getUploaderUrl() {
         return SoundcloudParsingHelper.getUploaderUrl(playlist);
@@ -123,24 +120,6 @@ public class SoundcloudPlaylistExtractor extends PlaylistExtractor {
         return playlist.getLong("track_count");
     }
 
-    @Nonnull
-    @Override
-    public String getSubChannelName() {
-        return "";
-    }
-
-    @Nonnull
-    @Override
-    public String getSubChannelUrl() {
-        return "";
-    }
-
-    @Nonnull
-    @Override
-    public String getSubChannelAvatarUrl() {
-        return "";
-    }
-
     @Nonnull
     @Override
     public InfoItemsPage<StreamInfoItem> getInitialPage() {
@@ -148,19 +127,21 @@ public class SoundcloudPlaylistExtractor extends PlaylistExtractor {
                 new StreamInfoItemsCollector(getServiceId());
         final List<String> ids = new ArrayList<>();
 
-        final JsonArray tracks = playlist.getArray("tracks");
+        playlist.getArray("tracks")
-        for (final Object o : tracks) {
+                .stream()
-            if (o instanceof JsonObject) {
+                .filter(JsonObject.class::isInstance)
-                final JsonObject track = (JsonObject) o;
+                .map(JsonObject.class::cast)
-                if (track.has("title")) { // i.e. if full info is available
+                .forEachOrdered(track -> {
-                    streamInfoItemsCollector.commit(new SoundcloudStreamInfoItemExtractor(track));
+                    // i.e. if full info is available
-                } else {
+                    if (track.has("title")) {
-                    // %09d would be enough, but a 0 before the number does not create problems, so
+                        streamInfoItemsCollector.commit(
-                    // let's be sure
+                                new SoundcloudStreamInfoItemExtractor(track));
-                    ids.add(String.format("%010d", track.getInt("id")));
+                    } else {
-                }
+                        // %09d would be enough, but a 0 before the number does not create
-            }
+                        // problems, so let's be sure
-        }
+                        ids.add(String.format("%010d", track.getInt("id")));
+                    }
+                });
 
         return new InfoItemsPage<>(streamInfoItemsCollector, new Page(ids));
     }

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubeMixPlaylistExtractor.java

@@ -23,6 +23,7 @@ import org.schabi.newpipe.extractor.utils.JsonUtils;
 
 import java.io.IOException;
 import java.net.URL;
+import java.nio.charset.StandardCharsets;
 import java.util.*;
 
 import javax.annotation.Nonnull;
@@ -71,7 +72,7 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
             jsonBody.value("playlistIndex", Integer.parseInt(playlistIndexString));
         }
 
-        final byte[] body = JsonWriter.string(jsonBody.done()).getBytes(UTF_8);
+        final byte[] body = JsonWriter.string(jsonBody.done()).getBytes(StandardCharsets.UTF_8);
 
         final Map<String, List<String>> headers = new HashMap<>();
         addClientInfoHeaders(headers);
@@ -97,6 +98,7 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
         return name;
     }
 
+    @Nonnull
     @Override
     public String getThumbnailUrl() throws ParsingException {
         try {
@@ -108,19 +110,15 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
                         .getObject("watchEndpoint").getString("videoId"));
             } catch (final Exception ignored) {
             }
+
             throw new ParsingException("Could not get playlist thumbnail", e);
         }
     }
 
-    @Override
-    public String getBannerUrl() {
-        return "";
-    }
-
     @Override
     public String getUploaderUrl() {
         // YouTube mixes are auto-generated by YouTube
-        return "";
+        return EMPTY_STRING;
     }
 
     @Override
@@ -132,7 +130,7 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
     @Override
     public String getUploaderAvatarUrl() {
         // YouTube mixes are auto-generated by YouTube
-        return "";
+        return EMPTY_STRING;
     }
 
     @Override
@@ -148,8 +146,8 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
 
     @Nonnull
     @Override
-    public InfoItemsPage<StreamInfoItem> getInitialPage() throws IOException,
+    public InfoItemsPage<StreamInfoItem> getInitialPage()
-            ExtractionException {
+            throws IOException, ExtractionException {
         final StreamInfoItemsCollector collector = new StreamInfoItemsCollector(getServiceId());
         collectStreamsFrom(collector, playlistData.getArray("contents"));
 
@@ -159,9 +157,10 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
         return new InfoItemsPage<>(collector, getNextPageFrom(playlistData, cookies));
     }
 
-    private Page getNextPageFrom(final JsonObject playlistJson,
+    @Nonnull
-                                 final Map<String, String> cookies) throws IOException,
+    private Page getNextPageFrom(@Nonnull final JsonObject playlistJson,
-            ExtractionException {
+                                 final Map<String, String> cookies)
+            throws IOException, ExtractionException {
         final JsonObject lastStream = ((JsonObject) playlistJson.getArray("contents")
                 .get(playlistJson.getArray("contents").size() - 1));
         if (lastStream == null || lastStream.getObject("playlistPanelVideoRenderer") == null) {
@@ -181,7 +180,7 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
                 .value("playlistIndex", index)
                 .value("params", params)
                 .done())
-                .getBytes(UTF_8);
+                .getBytes(StandardCharsets.UTF_8);
 
         return new Page(YOUTUBEI_V1_URL + "next?key=" + getKey(), null, null, cookies, body);
     }
@@ -217,26 +216,23 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
 
     private void collectStreamsFrom(@Nonnull final StreamInfoItemsCollector collector,
                                     @Nullable final List<Object> streams) {
-
         if (streams == null) {
             return;
         }
 
         final TimeAgoParser timeAgoParser = getTimeAgoParser();
 
-        for (final Object stream : streams) {
+        streams.stream()
-            if (stream instanceof JsonObject) {
+                .filter(JsonObject.class::isInstance)
-                final JsonObject streamInfo = ((JsonObject) stream)
+                .map(JsonObject.class::cast)
-                        .getObject("playlistPanelVideoRenderer");
+                .map(stream -> stream.getObject("playlistPanelVideoRenderer"))
-                if (streamInfo != null) {
+                .filter(Objects::nonNull)
-                    collector.commit(new YoutubeStreamInfoItemExtractor(streamInfo,
+                .map(streamInfo -> new YoutubeStreamInfoItemExtractor(streamInfo, timeAgoParser))
-                            timeAgoParser));
+                .forEachOrdered(collector::commit);
-                }
-            }
-        }
     }
 
-    private String getThumbnailUrlFromPlaylistId(final String playlistId) throws ParsingException {
+    @Nonnull
+    private String getThumbnailUrlFromPlaylistId(@Nonnull final String playlistId) throws ParsingException {
         final String videoId;
         if (playlistId.startsWith("RDMM")) {
             videoId = playlistId.substring(4);
@@ -251,25 +247,8 @@ public class YoutubeMixPlaylistExtractor extends PlaylistExtractor {
         return getThumbnailUrlFromVideoId(videoId);
     }
 
+    @Nonnull
     private String getThumbnailUrlFromVideoId(final String videoId) {
         return "https://i.ytimg.com/vi/" + videoId + "/hqdefault.jpg";
     }
-
-    @Nonnull
-    @Override
-    public String getSubChannelName() {
-        return "";
-    }
-
-    @Nonnull
-    @Override
-    public String getSubChannelUrl() {
-        return "";
-    }
-
-    @Nonnull
-    @Override
-    public String getSubChannelAvatarUrl() {
-        return "";
-    }
 }

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/extractors/YoutubePlaylistExtractor.java

@@ -21,22 +21,31 @@ import org.schabi.newpipe.extractor.utils.JsonUtils;
 import org.schabi.newpipe.extractor.utils.Utils;
 
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.*;
-import static org.schabi.newpipe.extractor.utils.Utils.UTF_8;
+import static org.schabi.newpipe.extractor.utils.Utils.*;
-import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
 
-@SuppressWarnings("WeakerAccess")
 public class YoutubePlaylistExtractor extends PlaylistExtractor {
-    private JsonObject initialData;
+    // Minimum size of the stats array in the browse response which includes the streams count
+    private static final int STATS_ARRAY_WITH_STREAMS_COUNT_MIN_SIZE = 2;
+
+    // Names of some objects in JSON response frequently used in this class
+    private static final String PLAYLIST_VIDEO_RENDERER = "playlistVideoRenderer";
+    private static final String PLAYLIST_VIDEO_LIST_RENDERER = "playlistVideoListRenderer";
+    private static final String VIDEO_OWNER_RENDERER = "videoOwnerRenderer";
+
+    private JsonObject browseResponse;
     private JsonObject playlistInfo;
 
-    public YoutubePlaylistExtractor(StreamingService service, ListLinkHandler linkHandler) {
+    public YoutubePlaylistExtractor(final StreamingService service,
+                                    final ListLinkHandler linkHandler) {
         super(service, linkHandler);
     }
 
@@ -45,41 +54,46 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
             ExtractionException {
         final Localization localization = getExtractorLocalization();
         final byte[] body = JsonWriter.string(prepareDesktopJsonBuilder(localization,
-                getExtractorContentCountry())
+                        getExtractorContentCountry())
-                .value("browseId", "VL" + getId())
+                        .value("browseId", "VL" + getId())
-                .value("params", "wgYCCAA%3D") // Show unavailable videos
+                        .value("params", "wgYCCAA%3D") // Show unavailable videos
-                .done())
+                        .done())
-                .getBytes(UTF_8);
+                .getBytes(StandardCharsets.UTF_8);
 
-        initialData = getJsonPostResponse("browse", body, localization);
+        browseResponse = getJsonPostResponse("browse", body, localization);
-        YoutubeParsingHelper.defaultAlertsCheck(initialData);
+        YoutubeParsingHelper.defaultAlertsCheck(browseResponse);
 
         playlistInfo = getPlaylistInfo();
     }
 
     private JsonObject getUploaderInfo() throws ParsingException {
-        final JsonArray items = initialData.getObject("sidebar")
+        final JsonArray items = browseResponse.getObject("sidebar")
-                .getObject("playlistSidebarRenderer").getArray("items");
+                .getObject("playlistSidebarRenderer")
+                .getArray("items");
 
         JsonObject videoOwner = items.getObject(1)
-                .getObject("playlistSidebarSecondaryInfoRenderer").getObject("videoOwner");
+                .getObject("playlistSidebarSecondaryInfoRenderer")
-        if (videoOwner.has("videoOwnerRenderer")) {
+                .getObject("videoOwner");
-            return videoOwner.getObject("videoOwnerRenderer");
+        if (videoOwner.has(VIDEO_OWNER_RENDERER)) {
+            return videoOwner.getObject(VIDEO_OWNER_RENDERER);
         }
 
         // we might want to create a loop here instead of using duplicated code
         videoOwner = items.getObject(items.size())
-                .getObject("playlistSidebarSecondaryInfoRenderer").getObject("videoOwner");
+                .getObject("playlistSidebarSecondaryInfoRenderer")
-        if (videoOwner.has("videoOwnerRenderer")) {
+                .getObject("videoOwner");
-            return videoOwner.getObject("videoOwnerRenderer");
+        if (videoOwner.has(VIDEO_OWNER_RENDERER)) {
+            return videoOwner.getObject(VIDEO_OWNER_RENDERER);
         }
         throw new ParsingException("Could not get uploader info");
     }
 
     private JsonObject getPlaylistInfo() throws ParsingException {
         try {
-            return initialData.getObject("sidebar").getObject("playlistSidebarRenderer")
+            return browseResponse.getObject("sidebar")
-                    .getArray("items").getObject(0)
+                    .getObject("playlistSidebarRenderer")
+                    .getArray("items")
+                    .getObject(0)
                     .getObject("playlistSidebarPrimaryInfoRenderer");
         } catch (final Exception e) {
             throw new ParsingException("Could not get PlaylistInfo", e);
@@ -90,33 +104,41 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
     @Override
     public String getName() throws ParsingException {
         final String name = getTextFromObject(playlistInfo.getObject("title"));
-        if (!isNullOrEmpty(name)) return name;
+        if (!isNullOrEmpty(name)) {
+            return name;
+        }
 
-        return initialData.getObject("microformat").getObject("microformatDataRenderer").getString("title");
+        return browseResponse.getObject("microformat")
+                .getObject("microformatDataRenderer")
+                .getString("title");
     }
 
+    @Nonnull
     @Override
     public String getThumbnailUrl() throws ParsingException {
-        String url = playlistInfo.getObject("thumbnailRenderer").getObject("playlistVideoThumbnailRenderer")
+        String url = playlistInfo.getObject("thumbnailRenderer")
-                .getObject("thumbnail").getArray("thumbnails").getObject(0).getString("url");
+                .getObject("playlistVideoThumbnailRenderer")
+                .getObject("thumbnail")
+                .getArray("thumbnails")
+                .getObject(0)
+                .getString("url");
 
         if (isNullOrEmpty(url)) {
-            url = initialData.getObject("microformat").getObject("microformatDataRenderer").getObject("thumbnail")
+            url = browseResponse.getObject("microformat")
-                    .getArray("thumbnails").getObject(0).getString("url");
+                    .getObject("microformatDataRenderer")
+                    .getObject("thumbnail")
+                    .getArray("thumbnails")
+                    .getObject(0)
+                    .getString("url");
 
-            if (isNullOrEmpty(url)) throw new ParsingException("Could not get playlist thumbnail");
+            if (isNullOrEmpty(url)) {
+                throw new ParsingException("Could not get playlist thumbnail");
+            }
         }
 
         return fixThumbnailUrl(url);
     }
 
-    @Override
-    public String getBannerUrl() {
-        // Banner can't be handled by frontend right now.
-        // Whoever is willing to implement this should also implement it in the frontend.
-        return "";
-    }
-
     @Override
     public String getUploaderUrl() throws ParsingException {
         try {
@@ -138,7 +160,11 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
     @Override
     public String getUploaderAvatarUrl() throws ParsingException {
         try {
-            final String url = getUploaderInfo().getObject("thumbnail").getArray("thumbnails").getObject(0).getString("url");
+            final String url = getUploaderInfo()
+                    .getObject("thumbnail")
+                    .getArray("thumbnails")
+                    .getObject(0)
+                    .getString("url");
 
             return fixThumbnailUrl(url);
         } catch (final Exception e) {
@@ -148,14 +174,29 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
 
     @Override
     public boolean isUploaderVerified() throws ParsingException {
+        // YouTube doesn't provide this information
         return false;
     }
 
     @Override
     public long getStreamCount() throws ParsingException {
         try {
-            final String viewsText = getTextFromObject(getPlaylistInfo().getArray("stats").getObject(0));
+            final JsonArray stats = playlistInfo.getArray("stats");
-            return Long.parseLong(Utils.removeNonDigitCharacters(viewsText));
+            // For unknown reasons, YouTube don't provide the stream count for learning playlists
+            // on the desktop client but only the number of views and the playlist modified date
+            // On normal playlists, at least 3 items are returned: the number of videos, the number
+            // of views and the playlist modification date
+            // We can get it by using another client, however it seems we can't get the avatar
+            // uploader URL with another client than the WEB client
+            if (stats.size() > STATS_ARRAY_WITH_STREAMS_COUNT_MIN_SIZE) {
+                final String videosText = getTextFromObject(playlistInfo.getArray("stats")
+                        .getObject(0));
+                if (videosText != null) {
+                    return Long.parseLong(Utils.removeNonDigitCharacters(videosText));
+                }
+            }
+
+            return ITEM_COUNT_UNKNOWN;
         } catch (final Exception e) {
             throw new ParsingException("Could not get video count from playlist", e);
         }
@@ -164,19 +205,19 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
     @Nonnull
     @Override
     public String getSubChannelName() {
-        return "";
+        return EMPTY_STRING;
     }
 
     @Nonnull
     @Override
     public String getSubChannelUrl() {
-        return "";
+        return EMPTY_STRING;
     }
 
     @Nonnull
     @Override
     public String getSubChannelAvatarUrl() {
-        return "";
+        return EMPTY_STRING;
     }
 
     @Nonnull
@@ -185,26 +226,32 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
         final StreamInfoItemsCollector collector = new StreamInfoItemsCollector(getServiceId());
         Page nextPage = null;
 
-        final JsonArray contents = initialData.getObject("contents")
+        final JsonArray contents = browseResponse.getObject("contents")
-                .getObject("twoColumnBrowseResultsRenderer").getArray("tabs").getObject(0)
+                .getObject("twoColumnBrowseResultsRenderer")
-                .getObject("tabRenderer").getObject("content").getObject("sectionListRenderer")
+                .getArray("tabs")
-                .getArray("contents").getObject(0).getObject("itemSectionRenderer")
+                .getObject(0)
+                .getObject("tabRenderer")
+                .getObject("content")
+                .getObject("sectionListRenderer")
                 .getArray("contents");
 
-        if (contents.getObject(0).has("playlistSegmentRenderer")) {
+        final JsonObject videoPlaylistObject = contents.stream()
-            for (final Object segment : contents) {
+                .filter(JsonObject.class::isInstance)
-                if (((JsonObject) segment).getObject("playlistSegmentRenderer")
+                .map(JsonObject.class::cast)
-                        .has("videoList")) {
+                .map(content -> content.getObject("itemSectionRenderer")
-                    collectStreamsFrom(collector, ((JsonObject) segment)
+                        .getArray("contents")
-                            .getObject("playlistSegmentRenderer").getObject("videoList")
+                        .getObject(0))
-                            .getObject("playlistVideoListRenderer").getArray("contents"));
+                .filter(contentItemSectionRendererContents ->
-                }
+                        contentItemSectionRendererContents.has(PLAYLIST_VIDEO_LIST_RENDERER)
-            }
+                                || contentItemSectionRendererContents.has(
+                                "playlistSegmentRenderer"))
+                .findFirst()
+                .orElse(null);
 
-            return new InfoItemsPage<>(collector, null);
+        if (videoPlaylistObject != null && videoPlaylistObject.has(PLAYLIST_VIDEO_LIST_RENDERER)) {
-        } else if (contents.getObject(0).has("playlistVideoListRenderer")) {
+            final JsonArray videosArray = videoPlaylistObject
-            final JsonObject videos = contents.getObject(0).getObject("playlistVideoListRenderer");
+                    .getObject(PLAYLIST_VIDEO_LIST_RENDERER)
-            final JsonArray videosArray = videos.getArray("contents");
+                    .getArray("contents");
             collectStreamsFrom(collector, videosArray);
 
             nextPage = getNextPageFrom(videosArray);
@@ -229,7 +276,8 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
         final JsonObject ajaxJson = JsonUtils.toJsonObject(getValidJsonResponseBody(response));
 
         final JsonArray continuation = ajaxJson.getArray("onResponseReceivedActions")
-                .getObject(0).getObject("appendContinuationItemsAction")
+                .getObject(0)
+                .getObject("appendContinuationItemsAction")
                 .getArray("continuationItems");
 
         collectStreamsFrom(collector, continuation);
@@ -237,8 +285,9 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
         return new InfoItemsPage<>(collector, getNextPageFrom(continuation));
     }
 
-    private Page getNextPageFrom(final JsonArray contents) throws IOException,
+    @Nullable
-            ExtractionException {
+    private Page getNextPageFrom(final JsonArray contents)
+            throws IOException, ExtractionException {
         if (isNullOrEmpty(contents)) {
             return null;
         }
@@ -252,10 +301,10 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
                     .getString("token");
 
             final byte[] body = JsonWriter.string(prepareDesktopJsonBuilder(
-                    getExtractorLocalization(), getExtractorContentCountry())
+                            getExtractorLocalization(), getExtractorContentCountry())
-                    .value("continuation", continuation)
+                            .value("continuation", continuation)
-                    .done())
+                            .done())
-                    .getBytes(UTF_8);
+                    .getBytes(StandardCharsets.UTF_8);
 
             return new Page(YOUTUBEI_V1_URL + "browse?key=" + getKey(), body);
         } else {
@@ -263,20 +312,21 @@ public class YoutubePlaylistExtractor extends PlaylistExtractor {
         }
     }
 
-    private void collectStreamsFrom(final StreamInfoItemsCollector collector,
+    private void collectStreamsFrom(@Nonnull final StreamInfoItemsCollector collector,
-                                    final JsonArray videos) {
+                                    @Nonnull final JsonArray videos) {
         final TimeAgoParser timeAgoParser = getTimeAgoParser();
 
-        for (final Object video : videos) {
+        videos.stream()
-            if (((JsonObject) video).has("playlistVideoRenderer")) {
+                .filter(JsonObject.class::isInstance)
-                collector.commit(new YoutubeStreamInfoItemExtractor(((JsonObject) video)
+                .map(JsonObject.class::cast)
-                        .getObject("playlistVideoRenderer"), timeAgoParser) {
+                .filter(video -> video.has(PLAYLIST_VIDEO_RENDERER))
+                .map(video -> new YoutubeStreamInfoItemExtractor(
+                        video.getObject(PLAYLIST_VIDEO_RENDERER), timeAgoParser) {
                     @Override
                     public long getViewCount() {
                         return -1;
                     }
-                });
+                })
-            }
+                .forEachOrdered(collector::commit);
-        }
     }
 }

extractor/src/test/java/org/schabi/newpipe/extractor/services/soundcloud/SoundcloudPlaylistExtractorTest.java

@@ -7,12 +7,14 @@ import org.schabi.newpipe.downloader.DownloaderTestImpl;
 import org.schabi.newpipe.extractor.ExtractorAsserts;
 import org.schabi.newpipe.extractor.ListExtractor;
 import org.schabi.newpipe.extractor.NewPipe;
+import org.schabi.newpipe.extractor.exceptions.ParsingException;
 import org.schabi.newpipe.extractor.playlist.PlaylistExtractor;
 import org.schabi.newpipe.extractor.services.BasePlaylistExtractorTest;
 import org.schabi.newpipe.extractor.services.soundcloud.extractors.SoundcloudPlaylistExtractor;
 import org.schabi.newpipe.extractor.stream.StreamInfoItem;
 
 import static org.junit.jupiter.api.Assertions.*;
+import static org.schabi.newpipe.extractor.ExtractorAsserts.assertEmpty;
 import static org.schabi.newpipe.extractor.ExtractorAsserts.assertIsSecureUrl;
 import static org.schabi.newpipe.extractor.ServiceList.SoundCloud;
 import static org.schabi.newpipe.extractor.services.DefaultTests.*;
@@ -85,9 +87,9 @@ public class SoundcloudPlaylistExtractorTest {
         }
 
         @Test
-        public void testBannerUrl() {
+        public void testBannerUrl() throws ParsingException {
             // SoundCloud playlists do not have a banner
-            assertNull(extractor.getBannerUrl());
+            assertEmpty(extractor.getBannerUrl());
         }
 
         @Test
@@ -182,9 +184,9 @@ public class SoundcloudPlaylistExtractorTest {
         }
 
         @Test
-        public void testBannerUrl() {
+        public void testBannerUrl() throws ParsingException {
             // SoundCloud playlists do not have a banner
-            assertNull(extractor.getBannerUrl());
+            assertEmpty(extractor.getBannerUrl());
         }
 
         @Test
@@ -294,9 +296,9 @@ public class SoundcloudPlaylistExtractorTest {
         }
 
         @Test
-        public void testBannerUrl() {
+        public void testBannerUrl() throws ParsingException {
             // SoundCloud playlists do not have a banner
-            assertNull(extractor.getBannerUrl());
+            assertEmpty(extractor.getBannerUrl());
         }
 
         @Test
@@ -398,9 +400,9 @@ public class SoundcloudPlaylistExtractorTest {
         }
 
         @Test
-        public void testBannerUrl() {
+        public void testBannerUrl() throws ParsingException {
             // SoundCloud playlists do not have a banner
-            assertNull(extractor.getBannerUrl());
+            assertEmpty(extractor.getBannerUrl());
         }
 
         @Test

extractor/src/test/java/org/schabi/newpipe/extractor/services/youtube/YoutubePlaylistExtractorTest.java

@@ -23,6 +23,7 @@ import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.schabi.newpipe.extractor.ExtractorAsserts.assertIsSecureUrl;
+import static org.schabi.newpipe.extractor.ListExtractor.ITEM_COUNT_UNKNOWN;
 import static org.schabi.newpipe.extractor.ServiceList.YouTube;
 import static org.schabi.newpipe.extractor.services.DefaultTests.assertNoMoreItems;
 import static org.schabi.newpipe.extractor.services.DefaultTests.defaultTestGetPageInNewExtractor;
@@ -129,7 +130,7 @@ public class YoutubePlaylistExtractorTest {
 
         @Disabled
         @Test
-        public void testBannerUrl() {
+        public void testBannerUrl() throws ParsingException {
             final String bannerUrl = extractor.getBannerUrl();
             assertIsSecureUrl(bannerUrl);
             ExtractorAsserts.assertContains("yt", bannerUrl);
@@ -249,7 +250,7 @@ public class YoutubePlaylistExtractorTest {
 
         @Disabled
         @Test
-        public void testBannerUrl() {
+        public void testBannerUrl() throws ParsingException {
             final String bannerUrl = extractor.getBannerUrl();
             assertIsSecureUrl(bannerUrl);
             ExtractorAsserts.assertContains("yt", bannerUrl);
@@ -352,7 +353,7 @@ public class YoutubePlaylistExtractorTest {
 
         @Disabled
         @Test
-        public void testBannerUrl() {
+        public void testBannerUrl() throws ParsingException {
             final String bannerUrl = extractor.getBannerUrl();
             assertIsSecureUrl(bannerUrl);
             ExtractorAsserts.assertContains("yt", bannerUrl);
@@ -377,7 +378,8 @@ public class YoutubePlaylistExtractorTest {
 
         @Test
         public void testStreamCount() throws Exception {
-            ExtractorAsserts.assertGreater(40, extractor.getStreamCount());
+            // We are not able to extract the stream count of YouTube learning playlists
+            assertEquals(ITEM_COUNT_UNKNOWN, extractor.getStreamCount());
         }
 
         @Override