[YT] Correctly resolve redirects when resolving channel ids

Author: litetex

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/YoutubeChannelHelper.java

@@ -1,26 +1,28 @@
 package org.schabi.newpipe.extractor.services.youtube;
 
+import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.defaultAlertsCheck;
+import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.getJsonPostResponse;
+import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.getTextFromObject;
+import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.hasArtistOrVerifiedIconBadgeAttachment;
+import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.prepareDesktopJsonBuilder;
+import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
+
 import com.grack.nanojson.JsonObject;
 import com.grack.nanojson.JsonWriter;
+
 import org.schabi.newpipe.extractor.exceptions.ContentNotAvailableException;
 import org.schabi.newpipe.extractor.exceptions.ExtractionException;
 import org.schabi.newpipe.extractor.exceptions.ParsingException;
 import org.schabi.newpipe.extractor.localization.ContentCountry;
 import org.schabi.newpipe.extractor.localization.Localization;
 
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import java.io.IOException;
 import java.io.Serializable;
 import java.nio.charset.StandardCharsets;
 import java.util.Optional;
 
-import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.defaultAlertsCheck;
-import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.getJsonPostResponse;
-import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.getTextFromObject;
-import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.hasArtistOrVerifiedIconBadgeAttachment;
-import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.prepareDesktopJsonBuilder;
-import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 /**
  * Shared functions for extracting YouTube channel pages and tabs.
@@ -65,25 +67,42 @@ public static String resolveChannelId(@Nonnull final String idOrPath)
         // URL, then no information about the channel associated with this URL was found,
         // so the unresolved url will be returned.
         if (!channelId[0].equals("channel")) {
-            final byte[] body = JsonWriter.string(
-                    prepareDesktopJsonBuilder(Localization.DEFAULT, ContentCountry.DEFAULT)
-                            .value("url", "https://www.youtube.com/" + idOrPath)
+            String urlToResolve = "https://www.youtube.com/" + idOrPath;
+
+            JsonObject endpoint = new JsonObject();
+            String webPageType = "";
+            // Try to resolve YT channel redirects
+            // It works like that:
+            // @TheDailyShow
+            // -> resolves to thedailyshow
+            // -> resolves to the id: UCwWhs_6x42TyRM4Wstoq8HA
+            for (int tries = 0;
+                 urlToResolve != null && tries < 3;
+                 tries++) {
+                final byte[] body = JsonWriter.string(
+                        prepareDesktopJsonBuilder(Localization.DEFAULT, ContentCountry.DEFAULT)
+                            .value("url", urlToResolve)
                             .done())
                     .getBytes(StandardCharsets.UTF_8);
 
-            final JsonObject jsonResponse = getJsonPostResponse(
+                final JsonObject jsonResponse = getJsonPostResponse(
                     "navigation/resolve_url", body, Localization.DEFAULT);
 
-            checkIfChannelResponseIsValid(jsonResponse);
+                checkIfChannelResponseIsValid(jsonResponse);
 
-            final JsonObject endpoint = jsonResponse.getObject("endpoint");
+                endpoint = jsonResponse.getObject("endpoint");
 
-            final String webPageType = endpoint.getObject("commandMetadata")
+                webPageType = endpoint.getObject("commandMetadata")
                     .getObject("webCommandMetadata")
                     .getString("webPageType", "");
 
-            final JsonObject browseEndpoint = endpoint.getObject(BROWSE_ENDPOINT);
-            final String browseId = browseEndpoint.getString(BROWSE_ID, "");
+                urlToResolve = "WEB_PAGE_TYPE_UNKNOWN".equals(webPageType)
+                    ? endpoint.getObject("urlEndpoint").getString("url")
+                    : null;
+            }
+
+            final String browseId = endpoint.getObject(BROWSE_ENDPOINT)
+                .getString(BROWSE_ID, "");
 
             if (webPageType.equalsIgnoreCase("WEB_PAGE_TYPE_BROWSE")
                     || webPageType.equalsIgnoreCase("WEB_PAGE_TYPE_CHANNEL")
@@ -94,6 +113,11 @@ public static String resolveChannelId(@Nonnull final String idOrPath)
 
                 return browseId;
             }
+
+            // Otherwise the code after that will run into an IndexOutOfBoundsException
+            if (channelId.length < 2) {
+                throw new ExtractionException("Failed to resolve channelId for " + idOrPath);
+            }
         }
 
         // return the unresolved URL