Use the youtubei API for YouTube searches + update mocks + ignore a test

Add getSearchParameter, a new method in YoutubeSearchQueryHandlerFactory class which returns the params field for a search, or an empty string if there is no one.
Update mocks of YoutubeSearchExtractorTest.
Ignore StreamSegmentsTestOstCollection test of YoutubeStreamExtractorDefaultTest because the video is now only available in China.

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

@@ -22,6 +22,7 @@
 import java.util.List;
 import java.util.Map;
 
+import static org.schabi.newpipe.extractor.services.youtube.linkHandler.YoutubeSearchQueryHandlerFactory.getSearchParameter;
 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.isNullOrEmpty;
@@ -55,11 +56,33 @@ public YoutubeSearchExtractor(final StreamingService service, final SearchQueryH
 
     @Override
     public void onFetchPage(@Nonnull final Downloader downloader) throws IOException, ExtractionException {
-        final String url = getUrl() + "&pbj=1";
+        final String query = super.getSearchString();
+
+        // Get the search parameter of the request
+        final List<String> contentFilters = super.getLinkHandler().getContentFilters();
+        final String params;
+        if (!isNullOrEmpty(contentFilters)) {
+            final String searchType = contentFilters.get(0);
+            params = getSearchParameter(searchType);
+        } else {
+            params = "";
+        }
 
-        final JsonArray ajaxJson = getJsonResponse(url, getExtractorLocalization());
+        final byte[] body;
+        if (!isNullOrEmpty(params)) {
+            body = JsonWriter.string(prepareJsonBuilder()
+                    .value("query", query)
+                    .value("params", params)
+                    .done())
+                    .getBytes(UTF_8);
+        } else {
+            body = JsonWriter.string(prepareJsonBuilder()
+                    .value("query", query)
+                    .done())
+                    .getBytes(UTF_8);
+        }
 
-        initialData = ajaxJson.getObject(1).getObject("response");
+        initialData = getJsonPostResponse("search", body, getExtractorLocalization());
     }
 
     @Nonnull

extractor/src/main/java/org/schabi/newpipe/extractor/services/youtube/linkHandler/YoutubeSearchQueryHandlerFactory.java

@@ -8,6 +8,7 @@
 import java.util.List;
 
 import static org.schabi.newpipe.extractor.utils.Utils.UTF_8;
+import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
 
 public class YoutubeSearchQueryHandlerFactory extends SearchQueryHandlerFactory {
 
@@ -72,4 +73,27 @@ public String[] getAvailableContentFilter() {
 //                MUSIC_ARTISTS
         };
     }
+
+    public static String getSearchParameter(final String contentFilter) {
+        if (!isNullOrEmpty(contentFilter)) {
+            switch (contentFilter) {
+                case VIDEOS:
+                    return "EgIQAQ%3D%3D";
+                case CHANNELS:
+                    return "EgIQAg%3D%3D";
+                case PLAYLISTS:
+                    return "EgIQAw%3D%3D";
+                case ALL:
+                case MUSIC_SONGS:
+                case MUSIC_VIDEOS:
+                case MUSIC_ALBUMS:
+                case MUSIC_PLAYLISTS:
+                case MUSIC_ARTISTS:
+                default:
+                    return "";
+            }
+        } else {
+            return "";
+        }
+    }
 }

extractor/src/test/java/org/schabi/newpipe/extractor/services/youtube/stream/YoutubeStreamExtractorDefaultTest.java

@@ -245,6 +245,7 @@ public static void setUp() throws Exception {
         // @formatter:on
     }
 
+    @Ignore("Test broken, video is only available in China")
     public static class StreamSegmentsTestOstCollection extends DefaultStreamExtractorTest {
         // StreamSegment example with single macro-makers panel
         private static final String ID = "2RYrHwnLHw0";