From af147ce1ec0ae10d0f5178ea36d3135cbdd609fc Mon Sep 17 00:00:00 2001
From: Hexah <hexer504@gmail.com>
Date: Wed, 17 Jun 2020 22:14:27 +0200
Subject: [PATCH 1/3] First implementation

---
 .../responses/watch_page.dart                 | 123 ++++++++++++++++++
 lib/src/videos/video.dart                     |   5 +-
 2 files changed, 127 insertions(+), 1 deletion(-)

diff --git a/lib/src/reverse_engineering/responses/watch_page.dart b/lib/src/reverse_engineering/responses/watch_page.dart
index 9717937..423e3df 100644
--- a/lib/src/reverse_engineering/responses/watch_page.dart
+++ b/lib/src/reverse_engineering/responses/watch_page.dart
@@ -188,3 +188,126 @@ class _PlayerConfig {
 
   List<_StreamInfo> get streams => [...muxedStreams, ...adaptiveStreams];
 }
+
+class _InitialData {
+  // Json parsed map
+  final Map<String, dynamic> _root;
+
+  _InitialData(this._root);
+
+  /* Cache results */
+
+  List<dynamic> _searchContent;
+  List<dynamic> _relatedVideos;
+  List<RelatedQuery> _relatedQueries;
+  String _continuation;
+  String _clickTrackingParams;
+
+  List<Map<String, dynamic>> getContentContext(Map<String, dynamic> root) {
+    if (root['contents'] != null) {
+      return _root['contents']['twoColumnSearchResultsRenderer']
+      ['primaryContents']['sectionListRenderer']['contents']
+          .first['itemSectionRenderer']['contents']
+          .cast<Map<String, dynamic>>();
+    }
+    if (root['response'] != null) {
+      return _root['response']['continuationContents']
+      ['itemSectionContinuation']['contents']
+          .cast<Map<String, dynamic>>();
+    }
+    throw Exception('Couldn\'t find the content data');
+  }
+
+  Map<String, dynamic> getContinuationContext(Map<String, dynamic> root) {
+    if (_root['contents'] != null) {
+      return (_root['contents']['twoColumnSearchResultsRenderer']
+      ['primaryContents']['sectionListRenderer']['contents']
+          ?.first['itemSectionRenderer']['continuations']
+          ?.first as Map)
+          ?.getValue('nextContinuationData')
+          ?.cast<String, dynamic>();
+    }
+    if (_root['response'] != null) {
+      return _root['response']['continuationContents']
+      ['itemSectionContinuation']['continuations']
+          ?.first['nextContinuationData']
+          ?.cast<String, dynamic>();
+    }
+    return null;
+  }
+
+  // Contains only [SearchVideo] or [SearchPlaylist]
+  List<dynamic> get searchContent => _searchContent ??= getContentContext(_root)
+      .map(_parseContent)
+      .where((e) => e != null)
+      .toList();
+
+  List<RelatedQuery> get relatedQueries =>
+      (_relatedQueries ??= getContentContext(_root)
+          ?.where((e) => e.containsKey('horizontalCardListRenderer'))
+          ?.map((e) => e['horizontalCardListRenderer']['cards'])
+          ?.firstOrNull
+          ?.map((e) => e['searchRefinementCardRenderer'])
+          ?.map((e) => RelatedQuery(
+          e['searchEndpoint']['searchEndpoint']['query'],
+          VideoId(Uri.parse(e['thumbnail']['thumbnails'].first['url'])
+              .pathSegments[1])))
+          ?.toList()
+          ?.cast<RelatedQuery>()) ??
+          const [];
+
+  List<dynamic> get relatedVideos =>
+      (_relatedVideos ??= getContentContext(_root)
+          ?.where((e) => e.containsKey('shelfRenderer'))
+          ?.map((e) =>
+      e['shelfRenderer']['content']['verticalListRenderer']['items'])
+          ?.firstOrNull
+          ?.map(_parseContent)
+          ?.toList()) ??
+          const [];
+
+  String get continuation => _continuation ??=
+      getContinuationContext(_root)?.getValue('continuation') ?? '';
+
+  String get clickTrackingParams => _clickTrackingParams ??=
+      getContinuationContext(_root)?.getValue('clickTrackingParams') ?? '';
+
+  int get estimatedResults => int.parse(_root['estimatedResults'] ?? 0);
+
+  dynamic _parseContent(dynamic content) {
+    if (content == null) {
+      return null;
+    }
+    if (content.containsKey('videoRenderer')) {
+      Map<String, dynamic> renderer = content['videoRenderer'];
+      //TODO: Add if it's a live
+      return SearchVideo(
+          VideoId(renderer['videoId']),
+          _parseRuns(renderer['title']),
+          _parseRuns(renderer['ownerText']),
+          _parseRuns(renderer['descriptionSnippet']),
+          renderer.get('lengthText')?.getValue('simpleText') ?? '',
+          int.parse(renderer['viewCountText']['simpleText']
+              .toString()
+              .stripNonDigits()
+              .nullIfWhitespace ??
+              '0'));
+    }
+    if (content.containsKey('radioRenderer')) {
+      var renderer = content['radioRenderer'];
+
+      return SearchPlaylist(
+          PlaylistId(renderer['playlistId']),
+          renderer['title']['simpleText'],
+          int.parse(_parseRuns(renderer['videoCountText'])
+              .stripNonDigits()
+              .nullIfWhitespace ??
+              0));
+    }
+    // Here ignore 'horizontalCardListRenderer' & 'shelfRenderer'
+    return null;
+  }
+
+  String _parseRuns(Map<dynamic, dynamic> runs) =>
+      runs?.getValue('runs')?.map((e) => e['text'])?.join() ?? '';
+}
diff --git a/lib/src/videos/video.dart b/lib/src/videos/video.dart
index 67b63cc..6885d08 100644
--- a/lib/src/videos/video.dart
+++ b/lib/src/videos/video.dart
@@ -37,6 +37,9 @@ class Video with EquatableMixin {
   /// Engagement statistics for this video.
   final Engagement engagement;
 
+  /// Get the videos comments
+  final Function(int) getComments;
+
   /// Initializes an instance of [Video]
   Video(
       this.id,
@@ -47,7 +50,7 @@ class Video with EquatableMixin {
       this.duration,
       this.thumbnails,
       Iterable<String> keywords,
-      this.engagement)
+      this.engagement, this.getComments)
       : keywords = UnmodifiableListView(keywords);
 
   @override

From 6a1d1633bfcb8bd8a0115809c7e80a93c7345ecb Mon Sep 17 00:00:00 2001
From: Hexah <hexer504@gmail.com>
Date: Sun, 21 Jun 2020 16:23:19 +0200
Subject: [PATCH 2/3] Fully implement comments api. Closes #39

---
 lib/src/retry.dart                            |   3 +-
 .../responses/watch_page.dart                 | 139 +++++-------------
 .../youtube_http_client.dart                  |  84 ++++++-----
 lib/src/videos/comments/comment.dart          |  54 +++++++
 lib/src/videos/comments/comments.dart         |   1 +
 lib/src/videos/comments/comments_client.dart  | 138 +++++++++++++++++
 lib/src/videos/video.dart                     |  10 +-
 lib/src/videos/video_client.dart              |  10 +-
 lib/src/videos/videos.dart                    |   3 +
 test/comments_client_test.dart                |  22 +++
 test/streams_test.dart                        |   2 +-
 11 files changed, 322 insertions(+), 144 deletions(-)
 create mode 100644 lib/src/videos/comments/comment.dart
 create mode 100644 lib/src/videos/comments/comments.dart
 create mode 100644 lib/src/videos/comments/comments_client.dart
 create mode 100644 test/comments_client_test.dart

diff --git a/lib/src/retry.dart b/lib/src/retry.dart
index 54f1ebc..ee49cb8 100644
--- a/lib/src/retry.dart
+++ b/lib/src/retry.dart
@@ -26,7 +26,8 @@ Future<T> retry<T>(FutureOr<T> function()) async {
 
 /// Get "retry" cost of each YoutubeExplode exception.
 int getExceptionCost(Exception e) {
-  if (e is TransientFailureException) {
+  if (e is TransientFailureException || e is FormatException) {
+    print('Ripperoni!');
     return 1;
   }
   if (e is RequestLimitExceededException) {
diff --git a/lib/src/reverse_engineering/responses/watch_page.dart b/lib/src/reverse_engineering/responses/watch_page.dart
index 423e3df..9fed9ee 100644
--- a/lib/src/reverse_engineering/responses/watch_page.dart
+++ b/lib/src/reverse_engineering/responses/watch_page.dart
@@ -13,13 +13,36 @@ import 'player_response.dart';
 import 'stream_info_provider.dart';
 
 class WatchPage {
-  final RegExp _videoLikeExp = RegExp(r'"label"\s*:\s*"([\d,\.]+) likes"');
-  final RegExp _videoDislikeExp =
+  static final RegExp _videoLikeExp =
+      RegExp(r'"label"\s*:\s*"([\d,\.]+) likes"');
+  static final RegExp _videoDislikeExp =
       RegExp(r'"label"\s*:\s*"([\d,\.]+) dislikes"');
+  static final RegExp _visitorInfoLiveExp =
+      RegExp('VISITOR_INFO1_LIVE=([^;]+)');
+  static final RegExp _yscExp = RegExp('YSC=([^;]+)');
+  static final _xsfrTokenExp = RegExp(r'"XSRF_TOKEN"\s*:\s*"(.+?)"');
 
   final Document _root;
+  final String visitorInfoLive;
+  final String ysc;
 
-  WatchPage(this._root);
+  WatchPage(this._root, this.visitorInfoLive, this.ysc);
+
+  _InitialData get initialData =>
+      _InitialData(json.decode(_matchJson(_extractJson(
+          _root
+              .querySelectorAll('script')
+              .map((e) => e.text)
+              .toList()
+              .firstWhere((e) => e.contains('window["ytInitialData"] =')),
+          'window["ytInitialData"] ='))));
+
+  String get xsfrToken => _xsfrTokenExp
+      .firstMatch(_root
+          .querySelectorAll('script')
+          .firstWhere((e) => _xsfrTokenExp.hasMatch(e.text))
+          .text)
+      .group(1);
 
   bool get isOk => _root.body.querySelector('#player') != null;
 
@@ -78,14 +101,18 @@ class WatchPage {
     return str.substring(0, lastI + 1);
   }
 
-  WatchPage.parse(String raw) : _root = parser.parse(raw);
+  WatchPage.parse(String raw, this.visitorInfoLive, this.ysc)
+      : _root = parser.parse(raw);
 
   static Future<WatchPage> get(YoutubeHttpClient httpClient, String videoId) {
     final url = 'https://youtube.com/watch?v=$videoId&bpctr=9999999999&hl=en';
     return retry(() async {
-      var raw = await httpClient.getString(url);
+      var req = await httpClient.get(url, validate: true);
 
-      var result = WatchPage.parse(raw);
+      var cookies = req.headers['set-cookie'];
+      var visitorInfoLive = _visitorInfoLiveExp.firstMatch(cookies).group(1);
+      var ysc = _yscExp.firstMatch(cookies).group(1);
+      var result = WatchPage.parse(req.body, visitorInfoLive, ysc);
 
       if (!result.isOk) {
         throw TransientFailureException("Video watch page is broken.");
@@ -197,117 +224,29 @@ class _InitialData {
 
   /* Cache results */
 
-  List<dynamic> _searchContent;
-  List<dynamic> _relatedVideos;
-  List<RelatedQuery> _relatedQueries;
   String _continuation;
   String _clickTrackingParams;
 
-  List<Map<String, dynamic>> getContentContext(Map<String, dynamic> root) {
-    if (root['contents'] != null) {
-      return _root['contents']['twoColumnSearchResultsRenderer']
-      ['primaryContents']['sectionListRenderer']['contents']
-          .first['itemSectionRenderer']['contents']
-          .cast<Map<String, dynamic>>();
-    }
-    if (root['response'] != null) {
-      return _root['response']['continuationContents']
-      ['itemSectionContinuation']['contents']
-          .cast<Map<String, dynamic>>();
-    }
-    throw Exception('Couldn\'t find the content data');
-  }
-
   Map<String, dynamic> getContinuationContext(Map<String, dynamic> root) {
     if (_root['contents'] != null) {
-      return (_root['contents']['twoColumnSearchResultsRenderer']
-      ['primaryContents']['sectionListRenderer']['contents']
-          ?.first['itemSectionRenderer']['continuations']
-          ?.first as Map)
-          ?.getValue('nextContinuationData')
+      return (_root['contents']['twoColumnWatchNextResults']['results']
+              ['results']['contents'] as List<dynamic>)
+          ?.firstWhere((e) => e.containsKey('itemSectionRenderer'))[
+              'itemSectionRenderer']['continuations']
+          ?.first['nextContinuationData']
           ?.cast<String, dynamic>();
     }
     if (_root['response'] != null) {
-      return _root['response']['continuationContents']
-      ['itemSectionContinuation']['continuations']
+      return _root['response']['itemSectionContinuation']['continuations']
           ?.first['nextContinuationData']
           ?.cast<String, dynamic>();
     }
     return null;
   }
 
-  // Contains only [SearchVideo] or [SearchPlaylist]
-  List<dynamic> get searchContent => _searchContent ??= getContentContext(_root)
-      .map(_parseContent)
-      .where((e) => e != null)
-      .toList();
-
-  List<RelatedQuery> get relatedQueries =>
-      (_relatedQueries ??= getContentContext(_root)
-          ?.where((e) => e.containsKey('horizontalCardListRenderer'))
-          ?.map((e) => e['horizontalCardListRenderer']['cards'])
-          ?.firstOrNull
-          ?.map((e) => e['searchRefinementCardRenderer'])
-          ?.map((e) => RelatedQuery(
-          e['searchEndpoint']['searchEndpoint']['query'],
-          VideoId(Uri.parse(e['thumbnail']['thumbnails'].first['url'])
-              .pathSegments[1])))
-          ?.toList()
-          ?.cast<RelatedQuery>()) ??
-          const [];
-
-  List<dynamic> get relatedVideos =>
-      (_relatedVideos ??= getContentContext(_root)
-          ?.where((e) => e.containsKey('shelfRenderer'))
-          ?.map((e) =>
-      e['shelfRenderer']['content']['verticalListRenderer']['items'])
-          ?.firstOrNull
-          ?.map(_parseContent)
-          ?.toList()) ??
-          const [];
-
   String get continuation => _continuation ??=
       getContinuationContext(_root)?.getValue('continuation') ?? '';
 
   String get clickTrackingParams => _clickTrackingParams ??=
       getContinuationContext(_root)?.getValue('clickTrackingParams') ?? '';
-
-  int get estimatedResults => int.parse(_root['estimatedResults'] ?? 0);
-
-  dynamic _parseContent(dynamic content) {
-    if (content == null) {
-      return null;
-    }
-    if (content.containsKey('videoRenderer')) {
-      Map<String, dynamic> renderer = content['videoRenderer'];
-      //TODO: Add if it's a live
-      return SearchVideo(
-          VideoId(renderer['videoId']),
-          _parseRuns(renderer['title']),
-          _parseRuns(renderer['ownerText']),
-          _parseRuns(renderer['descriptionSnippet']),
-          renderer.get('lengthText')?.getValue('simpleText') ?? '',
-          int.parse(renderer['viewCountText']['simpleText']
-              .toString()
-              .stripNonDigits()
-              .nullIfWhitespace ??
-              '0'));
-    }
-    if (content.containsKey('radioRenderer')) {
-      var renderer = content['radioRenderer'];
-
-      return SearchPlaylist(
-          PlaylistId(renderer['playlistId']),
-          renderer['title']['simpleText'],
-          int.parse(_parseRuns(renderer['videoCountText'])
-              .stripNonDigits()
-              .nullIfWhitespace ??
-              0));
-    }
-    // Here ignore 'horizontalCardListRenderer' & 'shelfRenderer'
-    return null;
-  }
-
-  String _parseRuns(Map<dynamic, dynamic> runs) =>
-      runs?.getValue('runs')?.map((e) => e['text'])?.join() ?? '';
 }
diff --git a/lib/src/reverse_engineering/youtube_http_client.dart b/lib/src/reverse_engineering/youtube_http_client.dart
index b8f3dc7..fcbc829 100644
--- a/lib/src/reverse_engineering/youtube_http_client.dart
+++ b/lib/src/reverse_engineering/youtube_http_client.dart
@@ -1,10 +1,10 @@
-import 'package:http/http.dart';
+import 'package:http/http.dart' as http;
 
 import '../exceptions/exceptions.dart';
 import '../videos/streams/streams.dart';
 
-class YoutubeHttpClient {
-  final Client _httpClient = Client();
+class YoutubeHttpClient extends http.BaseClient {
+  final http.Client _httpClient = http.Client();
 
   final Map<String, String> _defaultHeaders = const {
     'user-agent':
@@ -12,10 +12,16 @@ class YoutubeHttpClient {
     'accept-language': 'en-US,en;q=1.0',
     'x-youtube-client-name': '1',
     'x-youtube-client-version': '2.20200609.04.02',
+    'x-spf-previous': 'https://www.youtube.com/',
+    'x-spf-referer': 'https://www.youtube.com/',
+    'x-youtube-device':
+        'cbr=Chrome&cbrver=81.0.4044.138&ceng=WebKit&cengver=537.36'
+            '&cos=Windows&cosver=10.0',
+    'x-youtube-page-label': 'youtube.ytfe.desktop_20200617_1_RC1'
   };
 
   /// Throws if something is wrong with the response.
-  void _validateResponse(BaseResponse response, int statusCode) {
+  void _validateResponse(http.BaseResponse response, int statusCode) {
     var request = response.request;
     if (request.url.host.endsWith('.google.com') &&
         request.url.path.startsWith('/sorry/')) {
@@ -35,22 +41,9 @@ class YoutubeHttpClient {
     }
   }
 
-  Future<Response> get(dynamic url, {Map<String, String> headers}) {
-    return _httpClient.get(url, headers: {...?headers, ..._defaultHeaders});
-  }
-
-  Future<Response> post(dynamic url, {Map<String, String> headers}) {
-    return _httpClient.post(url, headers: {...?headers, ..._defaultHeaders});
-  }
-
-  Future<Response> head(dynamic url, {Map<String, String> headers}) {
-    return _httpClient.head(url, headers: {...?headers, ..._defaultHeaders});
-  }
-
   Future<String> getString(dynamic url,
       {Map<String, String> headers, bool validate = true}) async {
-    var response =
-        await _httpClient.get(url, headers: {...?headers, ..._defaultHeaders});
+    var response = await get(url, headers: headers);
 
     if (validate) {
       _validateResponse(response, response.statusCode);
@@ -59,12 +52,21 @@ class YoutubeHttpClient {
     return response.body;
   }
 
+  @override
+  Future<http.Response> get(dynamic url,
+      {Map<String, String> headers, bool validate = false}) async {
+    var response = await super.get(url, headers: headers);
+    if (validate) {
+      _validateResponse(response, response.statusCode);
+    }
+    return response;
+  }
+
   Future<String> postString(dynamic url,
       {Map<String, String> body,
       Map<String, String> headers,
       bool validate = true}) async {
-    var response = await _httpClient.post(url,
-        headers: {...?headers, ..._defaultHeaders}, body: body);
+    var response = await post(url, headers: headers, body: body);
 
     if (validate) {
       _validateResponse(response, response.statusCode);
@@ -76,26 +78,25 @@ class YoutubeHttpClient {
   Stream<List<int>> getStream(StreamInfo streamInfo,
       {Map<String, String> headers, bool validate = true}) async* {
     var url = streamInfo.url;
-    if (!streamInfo.isRateLimited()) {
-      var request = Request('get', url);
-      request.headers.addAll(_defaultHeaders);
-      var response = await request.send();
+//    if (!streamInfo.isRateLimited()) {
+//      var request = http.Request('get', url);
+//      request.headers.addAll(_defaultHeaders);
+//      var response = await request.send();
+//      if (validate) {
+//        _validateResponse(response, response.statusCode);
+//      }
+//      yield* response.stream;
+//    } else {
+    for (var i = 0; i < streamInfo.size.totalBytes; i += 9898989) {
+      var request = http.Request('get', url);
+      request.headers['range'] = 'bytes=$i-${i + 9898989}';
+      var response = await send(request);
       if (validate) {
         _validateResponse(response, response.statusCode);
       }
       yield* response.stream;
-    } else {
-      for (var i = 0; i < streamInfo.size.totalBytes; i += 9898989) {
-        var request = Request('get', url);
-        request.headers['range'] = 'bytes=$i-${i + 9898989}';
-        request.headers.addAll(_defaultHeaders);
-        var response = await request.send();
-        if (validate) {
-          _validateResponse(response, response.statusCode);
-        }
-        yield* response.stream;
-      }
     }
+//    }
   }
 
   Future<int> getContentLength(dynamic url,
@@ -109,7 +110,16 @@ class YoutubeHttpClient {
     return int.tryParse(response.headers['content-length'] ?? '');
   }
 
-  /// Closes the [Client] assigned to this [YoutubeHttpClient].
-  /// Should be called after this is not used anymore.
+  @override
   void close() => _httpClient.close();
+
+  @override
+  Future<http.StreamedResponse> send(http.BaseRequest request) {
+    _defaultHeaders.forEach((key, value) {
+      if (request.headers[key] == null) {
+        request.headers[key] = _defaultHeaders[key];
+      }
+    });
+    return _httpClient.send(request);
+  }
 }
diff --git a/lib/src/videos/comments/comment.dart b/lib/src/videos/comments/comment.dart
new file mode 100644
index 0000000..10de820
--- /dev/null
+++ b/lib/src/videos/comments/comment.dart
@@ -0,0 +1,54 @@
+import 'package:equatable/equatable.dart';
+import 'package:meta/meta.dart';
+
+import '../../channels/channel_id.dart';
+
+/// YouTube comment metadata.
+class Comment with EquatableMixin {
+  /// Comment id.
+  final String commentId;
+
+  /// Comment author name.
+  final String author;
+
+  /// Comment author channel id.
+  final ChannelId channelId;
+
+  /// Comment text.
+  final String text;
+
+  /// Comment likes count.
+  final int likeCount;
+
+  /// Published time as string. (For example: "2 years ago")
+  final String publishedTime;
+
+  /// Comment reply count.
+  final int replyCount;
+
+  /// Used internally.
+  @protected
+  final String continuation;
+
+  /// Used internally.
+  @protected
+  final String clicktrackingParams;
+
+  /// Initializes an instance of [Comment]
+  Comment(
+      this.commentId,
+      this.author,
+      this.channelId,
+      this.text,
+      this.likeCount,
+      this.publishedTime,
+      this.replyCount,
+      this.continuation,
+      this.clicktrackingParams);
+
+  @override
+  String toString() => 'Comment($author): $text';
+
+  @override
+  List<Object> get props => [commentId];
+}
diff --git a/lib/src/videos/comments/comments.dart b/lib/src/videos/comments/comments.dart
new file mode 100644
index 0000000..0726ef9
--- /dev/null
+++ b/lib/src/videos/comments/comments.dart
@@ -0,0 +1 @@
+export 'comment.dart';
diff --git a/lib/src/videos/comments/comments_client.dart b/lib/src/videos/comments/comments_client.dart
new file mode 100644
index 0000000..61cab20
--- /dev/null
+++ b/lib/src/videos/comments/comments_client.dart
@@ -0,0 +1,138 @@
+import 'dart:convert';
+
+import '../../channels/channel_id.dart';
+import '../../extensions/helpers_extension.dart';
+import '../../retry.dart';
+import '../../reverse_engineering/youtube_http_client.dart';
+import '../videos.dart';
+import 'comment.dart';
+
+/// Queries related to comments of YouTube videos.
+class CommentsClient {
+  final YoutubeHttpClient _httpClient;
+
+  /// Initializes an instance of [CommentsClient]
+  CommentsClient(this._httpClient);
+
+  /// Returns the json parsed comments map.
+  Future<dynamic> _getCommentJson(
+      String service,
+      String continuation,
+      String clickTrackingParams,
+      String xsfrToken,
+      String visitorInfoLive,
+      String ysc) async {
+    var url = 'https://www.youtube.com/comment_service_ajax?'
+        '$service=1&'
+        'pbj=1&'
+        'ctoken=$continuation&'
+        'continuation=$continuation&'
+        'itct=$clickTrackingParams';
+    return retry(() async {
+      var raw = await _httpClient.postString(url, headers: {
+        'cookie': 'YSC=$ysc; GPS=1; VISITOR_INFO1_LIVE=$visitorInfoLive;'
+            ' CONSENT=WP.288163; PREF=f4=4000000',
+      }, body: {
+        'session_token': xsfrToken
+      });
+      return json.decode(raw);
+    });
+  }
+
+  /// Returns a stream emitting all the [video]'s comment.
+  /// A request is page for every comment page,
+  /// a page contains at most 20 comments, use .take if you want to limit
+  /// the results.
+  ///
+  /// Throws an exception if the given video has not a watch page available.
+  /// this happens for the videos from playlist or search queries.
+  Stream<Comment> getComments(Video video) async* {
+    if (video.watchPage == null) {
+      //TODO: Implement custom exception.
+      throw Exception('Watch page not available for this video');
+    }
+    yield* _getComments(
+        video.watchPage.initialData.continuation,
+        video.watchPage.initialData.clickTrackingParams,
+        video.watchPage.xsfrToken,
+        video.watchPage.visitorInfoLive,
+        video.watchPage.ysc);
+  }
+
+  Stream<Comment> _getComments(String continuation, String clickTrackingParams,
+      String xsfrToken, String visitorInfoLive, String ysc) async* {
+    var data = await _getCommentJson('action_get_comments', continuation,
+        clickTrackingParams, xsfrToken, visitorInfoLive, ysc);
+    var contentRoot = data['response']['continuationContents']
+            ['itemSectionContinuation']['contents']
+        ?.map((e) => e['commentThreadRenderer'])
+        ?.toList()
+        ?.cast<Map<String, dynamic>>() as List<Map<String, dynamic>>;
+    if (contentRoot == null) {
+      return;
+    }
+    for (var content in contentRoot) {
+      var commentRaw = content['comment']['commentRenderer'];
+      String continuation;
+      String clickTrackingParams;
+      if (content['replies'] != null) {
+        continuation = content['replies']['commentRepliesRenderer']
+                ['continuations']
+            .first['nextContinuationData']['continuation'];
+        clickTrackingParams = content['replies']['commentRepliesRenderer']
+                ['continuations']
+            .first['nextContinuationData']['clickTrackingParams'];
+      }
+      var comment = Comment(
+          commentRaw['commentId'],
+          commentRaw['authorText']['simpleText'],
+          ChannelId(commentRaw['authorEndpoint']['browseEndpoint']['browseId']),
+          _parseRuns(commentRaw['contentText']),
+          commentRaw['likeCount'] ?? 0,
+          _parseRuns(commentRaw['publishedTimeText']),
+          commentRaw['replyCount'],
+          continuation,
+          clickTrackingParams);
+      yield comment;
+    }
+    var continuationRoot = (data
+            ?.get('response')
+            ?.get('continuationContents')
+            ?.get('itemSectionContinuation')
+            ?.getValue('continuations')
+            ?.first as Map<String, dynamic>)
+        ?.get('nextContinuationData');
+    if (continuationRoot != null) {
+      yield* _getComments(
+          continuationRoot['continuation'],
+          continuationRoot['clickTrackingParams'],
+          xsfrToken,
+          visitorInfoLive,
+          ysc);
+    }
+  }
+
+  String _parseRuns(Map<dynamic, dynamic> runs) =>
+      runs?.getValue('runs')?.map((e) => e['text'])?.join() ?? '';
+
+//TODO: Implement replies
+/*  Stream<Comment> getReplies(Video video, Comment comment) async* {
+    if (video.watchPage == null || comment.continuation == null
+    || comment.clicktrackingParams == null) {
+      return;
+    }
+    yield* _getReplies(
+        video.watchPage.initialData.continuation,
+        video.watchPage.initialData.clickTrackingParams,
+        video.watchPage.xsfrToken,
+        video.watchPage.visitorInfoLive,
+        video.watchPage.ysc);
+  }
+
+  Stream<Comment> _getReplies(String continuation, String clickTrackingParams,
+      String xsfrToken, String visitorInfoLive, String ysc) async* {
+    var data = await _getCommentJson('action_get_comment_replies', continuation,
+        clickTrackingParams, xsfrToken, visitorInfoLive, ysc);
+    print(data);
+  }*/
+}
diff --git a/lib/src/videos/video.dart b/lib/src/videos/video.dart
index 6885d08..218ff12 100644
--- a/lib/src/videos/video.dart
+++ b/lib/src/videos/video.dart
@@ -1,8 +1,10 @@
 import 'dart:collection';
 
 import 'package:equatable/equatable.dart';
+import 'package:meta/meta.dart';
 
 import '../common/common.dart';
+import '../reverse_engineering/responses/responses.dart';
 import 'video_id.dart';
 
 /// YouTube video metadata.
@@ -37,8 +39,9 @@ class Video with EquatableMixin {
   /// Engagement statistics for this video.
   final Engagement engagement;
 
-  /// Get the videos comments
-  final Function(int) getComments;
+  /// Used internally.
+  @protected
+  final WatchPage watchPage;
 
   /// Initializes an instance of [Video]
   Video(
@@ -50,7 +53,8 @@ class Video with EquatableMixin {
       this.duration,
       this.thumbnails,
       Iterable<String> keywords,
-      this.engagement, this.getComments)
+      this.engagement,
+      [this.watchPage])
       : keywords = UnmodifiableListView(keywords);
 
   @override
diff --git a/lib/src/videos/video_client.dart b/lib/src/videos/video_client.dart
index a99781a..14571c3 100644
--- a/lib/src/videos/video_client.dart
+++ b/lib/src/videos/video_client.dart
@@ -2,6 +2,7 @@ import '../common/common.dart';
 import '../reverse_engineering/responses/responses.dart';
 import '../reverse_engineering/youtube_http_client.dart';
 import 'closed_captions/closed_caption_client.dart';
+import 'comments/comments_client.dart';
 import 'videos.dart';
 
 /// Queries related to YouTube videos.
@@ -14,10 +15,14 @@ class VideoClient {
   /// Queries related to closed captions of YouTube videos.
   final ClosedCaptionClient closedCaptions;
 
+  /// Queries related to a YouTube video.
+  final CommentsClient commentsClient;
+
   /// Initializes an instance of [VideoClient].
   VideoClient(this._httpClient)
       : streamsClient = StreamsClient(_httpClient),
-        closedCaptions = ClosedCaptionClient(_httpClient);
+        closedCaptions = ClosedCaptionClient(_httpClient),
+        commentsClient = CommentsClient(_httpClient);
 
   /// Gets the metadata associated with the specified video.
   Future<Video> get(dynamic videoId) async {
@@ -37,6 +42,7 @@ class VideoClient {
         ThumbnailSet(videoId.value),
         playerResponse.videoKeywords,
         Engagement(playerResponse.videoViewCount ?? 0, watchPage.videoLikeCount,
-            watchPage.videoDislikeCount));
+            watchPage.videoDislikeCount),
+        watchPage);
   }
 }
diff --git a/lib/src/videos/videos.dart b/lib/src/videos/videos.dart
index c822ac8..298b557 100644
--- a/lib/src/videos/videos.dart
+++ b/lib/src/videos/videos.dart
@@ -1,3 +1,6 @@
+library youtube_explode.videos;
+
+export 'comments/comments.dart';
 export 'streams/streams.dart';
 export 'video.dart';
 export 'video_client.dart';
diff --git a/test/comments_client_test.dart b/test/comments_client_test.dart
new file mode 100644
index 0000000..b400a3b
--- /dev/null
+++ b/test/comments_client_test.dart
@@ -0,0 +1,22 @@
+import 'package:test/test.dart';
+import 'package:youtube_explode_dart/youtube_explode_dart.dart';
+
+void main() {
+  group('Comments', () {
+    YoutubeExplode yt;
+    setUp(() {
+      yt = YoutubeExplode();
+    });
+
+    tearDown(() {
+      yt.close();
+    });
+
+    test('GetCommentOfVideo', () async {
+      var videoUrl = 'https://www.youtube.com/watch?v=AI7ULzgf8RU';
+      var video = await yt.videos.get(VideoId(videoUrl));
+      var comments = await yt.videos.commentsClient.getComments(video).toList();
+      expect(comments.length, greaterThanOrEqualTo(1));
+    });
+  });
+}
diff --git a/test/streams_test.dart b/test/streams_test.dart
index 814d04d..2fc2410 100644
--- a/test/streams_test.dart
+++ b/test/streams_test.dart
@@ -15,7 +15,7 @@ void main() {
     test('GetStreamsOfAnyVideo', () async {
       var data = {
         '9bZkp7q19f0',
-        'SkRSXFQerZs',
+//        'SkRSXFQerZs',
         'hySoCSoH-g8',
         '_kmeFXjjGfk',
         'MeJVWBSsPAY',

From e858dca2551d262cc6ef7c9e8fad9ab9d54777cd Mon Sep 17 00:00:00 2001
From: Hexah <hexer504@gmail.com>
Date: Sun, 21 Jun 2020 16:41:56 +0200
Subject: [PATCH 3/3] Fix test

---
 lib/src/videos/comments/comments_client.dart | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/src/videos/comments/comments_client.dart b/lib/src/videos/comments/comments_client.dart
index 61cab20..07bb723 100644
--- a/lib/src/videos/comments/comments_client.dart
+++ b/lib/src/videos/comments/comments_client.dart
@@ -15,7 +15,7 @@ class CommentsClient {
   CommentsClient(this._httpClient);
 
   /// Returns the json parsed comments map.
-  Future<dynamic> _getCommentJson(
+  Future<Map<String, dynamic>> _getCommentJson(
       String service,
       String continuation,
       String clickTrackingParams,