[YouTube] Refactor some extraction code using Optional

Author: Isira-Seneviratne

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

@@ -519,22 +519,23 @@ public static String getChannelName(@Nullable final ChannelHeader channelHeader,
         }
 
         return Optional.ofNullable(channelHeader)
-                .map(header -> {
+                .flatMap(header -> {
                     final JsonObject channelJson = header.json;
                     switch (header.headerType) {
                         case PAGE:
-                            return channelJson.getObject(CONTENT)
+                            final String pageTitle = channelJson.getObject(CONTENT)
                                     .getObject(PAGE_HEADER_VIEW_MODEL)
                                     .getObject(TITLE)
                                     .getObject("dynamicTextViewModel")
                                     .getObject("text")
                                     .getString(CONTENT, channelJson.getString("pageTitle"));
+                            return Optional.ofNullable(pageTitle);
                         case CAROUSEL:
                         case INTERACTIVE_TABBED:
                             return getTextFromObject(channelJson.getObject(TITLE));
                         case C4_TABBED:
                         default:
-                            return channelJson.getString(TITLE);
+                            return Optional.ofNullable(channelJson.getString(TITLE));
                     }
                 })
                 // The channel name from a microformatDataRenderer may be different from the one

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

@@ -5,7 +5,6 @@
 import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.getTextFromObjectOrThrow;
 import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.getUrlFromNavigationEndpoint;
 import static org.schabi.newpipe.extractor.services.youtube.YoutubeParsingHelper.isGoogleURL;
-import static org.schabi.newpipe.extractor.utils.Utils.isNullOrEmpty;
 import static org.schabi.newpipe.extractor.utils.Utils.replaceHttpWithHttps;
 
 import com.grack.nanojson.JsonArray;
@@ -67,14 +66,11 @@ public static List<MetaInfo> getMetaInfo(@Nonnull final JsonArray contents)
     private static MetaInfo getInfoPanelContent(@Nonnull final JsonObject infoPanelContentRenderer)
             throws ParsingException {
         final MetaInfo metaInfo = new MetaInfo();
-        final StringBuilder sb = new StringBuilder();
-        for (final Object paragraph : infoPanelContentRenderer.getArray("paragraphs")) {
-            if (sb.length() != 0) {
-                sb.append("<br>");
-            }
-            sb.append(getTextFromObject((JsonObject) paragraph));
-        }
-        metaInfo.setContent(new Description(sb.toString(), Description.HTML));
+        final String description = infoPanelContentRenderer.getArray("paragraphs")
+                .streamAsJsonObjects()
+                .map(paragraph -> getTextFromObject(paragraph).orElse(""))
+                .collect(Collectors.joining("<br>"));
+        metaInfo.setContent(new Description(description, Description.HTML));
         if (infoPanelContentRenderer.has("sourceEndpoint")) {
             final String metaInfoLinkUrl = getUrlFromNavigationEndpoint(
                     infoPanelContentRenderer.getObject("sourceEndpoint"));
@@ -86,10 +82,9 @@ private static MetaInfo getInfoPanelContent(@Nonnull final JsonObject infoPanelC
             }
 
             final String metaInfoLinkText = getTextFromObject(
-                    infoPanelContentRenderer.getObject("inlineSource"));
-            if (isNullOrEmpty(metaInfoLinkText)) {
-                throw new ParsingException("Could not get metadata info link text.");
-            }
+                    infoPanelContentRenderer.getObject("inlineSource"))
+                    .orElseThrow(() ->
+                            new ParsingException("Could not get metadata info link text."));
             metaInfo.addUrlText(metaInfoLinkText);
         }
 
@@ -101,13 +96,12 @@ private static MetaInfo getClarificationRenderer(
             @Nonnull final JsonObject clarificationRenderer) throws ParsingException {
         final MetaInfo metaInfo = new MetaInfo();
 
-        final String title = getTextFromObject(clarificationRenderer
-                .getObject("contentTitle"));
-        final String text = getTextFromObject(clarificationRenderer
-                .getObject("text"));
-        if (title == null || text == null) {
-            throw new ParsingException("Could not extract clarification renderer content");
-        }
+        final String title = getTextFromObject(clarificationRenderer.getObject("contentTitle"))
+                .orElseThrow(() ->
+                        new ParsingException("Could not extract clarification renderer content"));
+        final String text = getTextFromObject(clarificationRenderer.getObject("text"))
+                .orElseThrow(() ->
+                        new ParsingException("Could not extract clarification renderer content"));
         metaInfo.setTitle(title);
         metaInfo.setContent(new Description(text, Description.PLAIN_TEXT));
 
@@ -122,11 +116,9 @@ private static MetaInfo getClarificationRenderer(
                 throw new ParsingException("Could not get metadata info URL", e);
             }
 
-            final String metaInfoLinkText = getTextFromObject(
-                    actionButton.getObject("text"));
-            if (isNullOrEmpty(metaInfoLinkText)) {
-                throw new ParsingException("Could not get metadata info link text.");
-            }
+            final String metaInfoLinkText = getTextFromObject(actionButton.getObject("text"))
+                    .orElseThrow(() ->
+                            new ParsingException("Could not get metadata info link text."));
             metaInfo.addUrlText(metaInfoLinkText);
         }
 
@@ -138,9 +130,9 @@ private static MetaInfo getClarificationRenderer(
             if (url != null && !isGoogleURL(url)) {
                 try {
                     metaInfo.addUrl(new URL(url));
-                    final String description = getTextFromObject(clarificationRenderer
-                            .getObject("secondarySource"));
-                    metaInfo.addUrlText(description == null ? url : description);
+                    final String urlText = getTextFromObject(clarificationRenderer
+                            .getObject("secondarySource")).orElse(url);
+                    metaInfo.addUrlText(urlText);
                 } catch (final MalformedURLException e) {
                     throw new ParsingException("Could not get metadata info secondary URL", e);
                 }

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

@@ -776,125 +776,80 @@ public static String getUrlFromNavigationEndpoint(
      *
      * @param textObject JSON object to get the text from
      * @param html       whether to return HTML, by parsing the {@code navigationEndpoint}
-     * @return text in the JSON object or {@code null}
+     * @return text in the JSON object as an {@link Optional}
      */
-    @Nullable
-    public static String getTextFromObject(final JsonObject textObject, final boolean html) {
-        if (isNullOrEmpty(textObject)) {
-            return null;
-        }
-
-        if (textObject.has("simpleText")) {
-            return textObject.getString("simpleText");
-        }
-
-        final JsonArray runs = textObject.getArray("runs");
-        if (runs.isEmpty()) {
-            return null;
-        }
-
-        final StringBuilder textBuilder = new StringBuilder();
-        for (final Object o : runs) {
-            final JsonObject run = (JsonObject) o;
-            String text = run.getString("text");
-
-            if (html) {
-                if (run.has("navigationEndpoint")) {
-                    final String url = getUrlFromNavigationEndpoint(
-                            run.getObject("navigationEndpoint"));
-                    if (!isNullOrEmpty(url)) {
-                        text = "<a href=\"" + Entities.escape(url) + "\">" + Entities.escape(text)
-                                + "</a>";
+    @Nonnull
+    public static Optional<String> getTextFromObject(@Nonnull final JsonObject textObject,
+                                                     final boolean html) {
+        return Optional.ofNullable(textObject.getString("simpleText"))
+                .or(() -> {
+                    final var runs = textObject.getArray("runs");
+                    final String text = runs.streamAsJsonObjects()
+                            .map(run -> {
+                                String textString = run.getString("text");
+
+                                if (html) {
+                                    final String url = getUrlFromNavigationEndpoint(
+                                            run.getObject("navigationEndpoint"));
+                                    if (!isNullOrEmpty(url)) {
+                                        textString = "<a href=\"" + Entities.escape(url) + "\">"
+                                                + Entities.escape(textString) + "</a>";
+                                    }
+
+                                    if (run.getBoolean("strikethrough")) {
+                                        textString = "<s>" + textString + "</s>";
+                                    }
+                                    if (run.getBoolean("italics")) {
+                                        textString = "<i>" + textString + "</i>";
+                                    }
+                                    if (run.getBoolean("bold")) {
+                                        textString = "<b>" + textString + "</b>";
+                                    }
+                                }
+
+                                return textString;
+                            })
+                            .collect(Collectors.joining());
+
+                    final String string;
+                    if (html) {
+                        string = text.replaceAll("\\n", "<br>")
+                                .replaceAll(" {2}", " &nbsp;");
+                    } else {
+                        string = text;
                     }
-                }
-
-                final boolean bold = run.has("bold")
-                        && run.getBoolean("bold");
-                final boolean italic = run.has("italics")
-                        && run.getBoolean("italics");
-                final boolean strikethrough = run.has("strikethrough")
-                        && run.getBoolean("strikethrough");
-
-                if (bold) {
-                    textBuilder.append("<b>");
-                }
-                if (italic) {
-                    textBuilder.append("<i>");
-                }
-                if (strikethrough) {
-                    textBuilder.append("<s>");
-                }
-
-                textBuilder.append(text);
-
-                if (strikethrough) {
-                    textBuilder.append("</s>");
-                }
-                if (italic) {
-                    textBuilder.append("</i>");
-                }
-                if (bold) {
-                    textBuilder.append("</b>");
-                }
-            } else {
-                textBuilder.append(text);
-            }
-        }
-
-        String text = textBuilder.toString();
-
-        if (html) {
-            text = text.replaceAll("\\n", "<br>");
-            text = text.replaceAll(" {2}", " &nbsp;");
-        }
-
-        return text;
+                    return Optional.of(string);
+                })
+                .filter(text -> !text.isEmpty());
     }
 
     @Nonnull
     public static String getTextFromObjectOrThrow(final JsonObject textObject, final String error)
             throws ParsingException {
-        final String result = getTextFromObject(textObject);
-        if (result == null) {
-            throw new ParsingException("Could not extract text: " + error);
-        }
-        return result;
+        return getTextFromObject(textObject)
+                .orElseThrow(() -> new ParsingException("Could not extract text: " + error));
     }
 
-    @Nullable
-    public static String getTextFromObject(final JsonObject textObject) {
+    @Nonnull
+    public static Optional<String> getTextFromObject(@Nonnull final JsonObject textObject) {
         return getTextFromObject(textObject, false);
     }
 
-    @Nullable
-    public static String getUrlFromObject(final JsonObject textObject) {
-        if (isNullOrEmpty(textObject)) {
-            return null;
-        }
-
-        final JsonArray runs = textObject.getArray("runs");
-        if (runs.isEmpty()) {
-            return null;
-        }
-
-        for (final Object textPart : runs) {
-            final String url = getUrlFromNavigationEndpoint(((JsonObject) textPart)
-                    .getObject("navigationEndpoint"));
-            if (!isNullOrEmpty(url)) {
-                return url;
-            }
-        }
-
-        return null;
+    @Nonnull
+    public static Optional<String> getUrlFromObject(@Nonnull final JsonObject textObject) {
+        return textObject.getArray("runs").streamAsJsonObjects()
+                .map(textPart -> getUrlFromNavigationEndpoint(textPart
+                        .getObject("navigationEndpoint")))
+                .filter(url -> !isNullOrEmpty(url))
+                .findFirst();
     }
 
-    @Nullable
-    public static String getTextAtKey(@Nonnull final JsonObject jsonObject, final String theKey) {
-        if (jsonObject.isString(theKey)) {
-            return jsonObject.getString(theKey);
-        } else {
-            return getTextFromObject(jsonObject.getObject(theKey));
-        }
+    @Nonnull
+    public static Optional<String> getTextAtKey(@Nonnull final JsonObject jsonObject,
+                                                final String theKey) {
+        return Optional.ofNullable(jsonObject.getString(theKey))
+                .filter(text -> !text.isEmpty())
+                .or(() -> getTextFromObject(jsonObject.getObject(theKey)));
     }
 
     public static String fixThumbnailUrl(@Nonnull final String thumbnailUrl) {
@@ -1222,7 +1177,8 @@ public static void defaultAlertsCheck(@Nonnull final JsonObject initialData)
         final JsonArray alerts = initialData.getArray("alerts");
         if (!isNullOrEmpty(alerts)) {
             final JsonObject alertRenderer = alerts.getObject(0).getObject("alertRenderer");
-            final String alertText = getTextFromObject(alertRenderer.getObject("text"));
+            final String alertText = getTextFromObject(alertRenderer.getObject("text"))
+                    .orElse(null);
             final String alertType = alertRenderer.getString("type", "");
             if (alertType.equalsIgnoreCase("ERROR")) {
                 if (alertText != null

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

@@ -49,10 +49,8 @@ public long getStreamCount() throws ParsingException {
         final String streamCountText = getTextFromObject(
                 showRenderer.getObject("thumbnailOverlays")
                         .getObject("thumbnailOverlayBottomPanelRenderer")
-                        .getObject("text"));
-        if (streamCountText == null) {
-            throw new ParsingException("Could not get stream count");
-        }
+                        .getObject("text"))
+                .orElseThrow(() -> new ParsingException("Could not get stream count"));
 
         try {
             // The data returned could be a human/shortened number, but no show with more than 1000

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

@@ -257,7 +257,7 @@ public long getSubscriberCount() throws ParsingException {
 
             if (textObject != null) {
                 try {
-                    return Utils.mixedNumberWordToLong(getTextFromObject(textObject));
+                    return Utils.mixedNumberWordToLong(getTextFromObject(textObject).orElse(""));
                 } catch (final NumberFormatException e) {
                     throw new ParsingException("Could not get subscriber count", e);
                 }
@@ -321,7 +321,8 @@ public String getDescription() throws ParsingException {
                 The description extracted is incomplete and the original one can be only
                 accessed from the About tab
                  */
-                return getTextFromObject(channelHeader.json.getObject("description"));
+                return getTextFromObject(channelHeader.json.getObject("description"))
+                        .orElse(null);
             }
 
             return jsonResponse.getObject(METADATA)