path: root/youtube/comments.py

from youtube import proto, util, yt_data_extract, accounts
from youtube import yt_app
import settings

import json
import base64
import urllib
import re

import flask
from flask import request

# Here's what I know about the secret key (starting with ASJN_i)
# *The secret key definitely contains the following information (or perhaps the information is stored at youtube's servers):
#   -Video id
#   -Offset
#   -Sort
# *If the video id or sort in the ctoken contradicts the ASJN, the response is an error. The offset encoded outside the ASJN is ignored entirely.
# *The ASJN is base64 encoded data, indicated by the fact that the character after "ASJN_i" is one of ("0", "1", "2", "3")
# *The encoded data is not valid protobuf
# *The encoded data (after the 5 or so bytes that are always the same) is indistinguishable from random data according to a battery of randomness tests
# *The ASJN in the ctoken provided by a response changes in regular intervals of about a second or two.
# *Old ASJN's continue to work, and start at the same comment even if new comments have been posted since
# *The ASJN has no relation with any of the data in the response it came from

def make_comment_ctoken(video_id, sort=0, offset=0, lc='', secret_key=''):
    video_id = proto.as_bytes(video_id)
    secret_key = proto.as_bytes(secret_key)
    

    page_info = proto.string(4,video_id) + proto.uint(6, sort)
    offset_information = proto.nested(4, page_info) + proto.uint(5, offset)
    if secret_key:
        offset_information = proto.string(1, secret_key) + offset_information

    page_params = proto.string(2, video_id)
    if lc:
        page_params += proto.string(6, proto.percent_b64encode(proto.string(15, lc)))

    result = proto.nested(2, page_params) + proto.uint(3,6) + proto.nested(6, offset_information)
    return base64.urlsafe_b64encode(result).decode('ascii')

def comment_replies_ctoken(video_id, comment_id, max_results=500):  

    params = proto.string(2, comment_id) + proto.uint(9, max_results)
    params = proto.nested(3, params)
    
    result = proto.nested(2, proto.string(2, video_id)) + proto.uint(3,6) + proto.nested(6, params)
    return base64.urlsafe_b64encode(result).decode('ascii')

def ctoken_metadata(ctoken):
    result = dict()
    params = proto.parse(proto.b64_to_bytes(ctoken))
    result['video_id'] = proto.parse(params[2])[2].decode('ascii')

    offset_information = proto.parse(params[6])
    result['offset'] = offset_information.get(5, 0)

    result['is_replies'] = False
    if (3 in offset_information) and (2 in proto.parse(offset_information[3])):
        result['is_replies'] = True
        result['sort'] = None
    else:
        try:
            result['sort'] = proto.parse(offset_information[4])[6]
        except KeyError:
            result['sort'] = 0
    return result


mobile_headers = {
    'User-Agent': 'Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.0 Mobile/14E304 Safari/602.1',
    'Accept': '*/*',
    'Accept-Language': 'en-US,en;q=0.5',
    'X-YouTube-Client-Name': '2',
    'X-YouTube-Client-Version': '2.20180823',
}
def request_comments(ctoken, replies=False):
    if replies: # let's make it use different urls for no reason despite all the data being encoded
        base_url = "https://m.youtube.com/watch_comment?action_get_comment_replies=1&ctoken="
    else:
        base_url = "https://m.youtube.com/watch_comment?action_get_comments=1&ctoken="
    url = base_url + ctoken.replace("=", "%3D") + "&pbj=1"

    for i in range(0,8):    # don't retry more than 8 times
        content = util.fetch_url(url, headers=mobile_headers, report_text="Retrieved comments", debug_name='request_comments')
        if content[0:4] == b")]}'":             # random closing characters included at beginning of response for some reason
            content = content[4:]
        elif content[0:10] == b'\n<!DOCTYPE':   # occasionally returns html instead of json for no reason
            content = b''
            print("got <!DOCTYPE>, retrying")
            continue
        break
    return content


def single_comment_ctoken(video_id, comment_id):
    page_params = proto.string(2, video_id) + proto.string(6, proto.percent_b64encode(proto.string(15, comment_id)))

    result = proto.nested(2, page_params) + proto.uint(3,6)
    return base64.urlsafe_b64encode(result).decode('ascii')



def parse_comments_polymer(content):
    try:
        video_title = ''
        content = json.loads(util.uppercase_escape(content.decode('utf-8')))
        url = content[1]['url']
        ctoken = urllib.parse.parse_qs(url[url.find('?')+1:])['ctoken'][0]
        metadata = ctoken_metadata(ctoken)

        try:
            comments_raw = content[1]['response']['continuationContents']['commentSectionContinuation']['items']
        except KeyError:
            comments_raw = content[1]['response']['continuationContents']['commentRepliesContinuation']['contents']

        ctoken = util.default_multi_get(content, 1, 'response', 'continuationContents', 'commentSectionContinuation', 'continuations', 0, 'nextContinuationData', 'continuation', default='')

        comments = []
        for comment_json in comments_raw:
            number_of_replies = 0
            try:
                comment_thread = comment_json['commentThreadRenderer']
            except KeyError:
                comment_renderer = comment_json['commentRenderer']
            else:
                if 'commentTargetTitle' in comment_thread:
                    video_title = comment_thread['commentTargetTitle']['runs'][0]['text']

                if 'replies' in comment_thread:
                    view_replies_text = yt_data_extract.get_plain_text(comment_thread['replies']['commentRepliesRenderer']['moreText'])
                    view_replies_text = view_replies_text.replace(',', '')
                    match = re.search(r'(\d+)', view_replies_text)
                    if match is None:
                        number_of_replies = 1
                    else:
                        number_of_replies = int(match.group(1))
                comment_renderer = comment_thread['comment']['commentRenderer']

            comment = {
                'author_id': comment_renderer.get('authorId', ''),
                'author_avatar': comment_renderer['authorThumbnail']['thumbnails'][0]['url'],
                'likes': comment_renderer['likeCount'],
                'published': yt_data_extract.get_plain_text(comment_renderer['publishedTimeText']),
                'text': comment_renderer['contentText'].get('runs', ''),
                'number_of_replies': number_of_replies,
                'comment_id': comment_renderer['commentId'],
            }

            if 'authorText' in comment_renderer:     # deleted channels have no name or channel link
                comment['author'] = yt_data_extract.get_plain_text(comment_renderer['authorText'])
                comment['author_url'] = comment_renderer['authorEndpoint']['commandMetadata']['webCommandMetadata']['url']
                comment['author_channel_id'] = comment_renderer['authorEndpoint']['browseEndpoint']['browseId']
            else:
                comment['author'] = ''
                comment['author_url'] = ''
                comment['author_channel_id'] = ''

            comments.append(comment)
    except Exception as e:
        print('Error parsing comments: ' + str(e))
        comments = ()
        ctoken = ''

    return {
        'ctoken': ctoken,
        'comments': comments,
        'video_title': video_title,
        'video_id': metadata['video_id'],
        'offset': metadata['offset'],
        'is_replies': metadata['is_replies'],
        'sort': metadata['sort'],
    }

def post_process_comments_info(comments_info):
    for comment in comments_info['comments']:
        comment['author_url'] = util.URL_ORIGIN + comment['author_url']
        comment['author_avatar'] = '/' + comment['author_avatar']

        comment['permalink'] = util.URL_ORIGIN + '/watch?v=' + comments_info['video_id'] + '&lc=' + comment['comment_id']

        if comment['author_channel_id'] in accounts.accounts:
            comment['delete_url'] = (util.URL_ORIGIN + '/delete_comment?video_id='
                + comments_info['video_id']
                + '&channel_id='+ comment['author_channel_id']
                + '&author_id=' + comment['author_id']
                + '&comment_id=' + comment['comment_id'])

        num_replies = comment['number_of_replies']
        if num_replies == 0:
            comment['replies_url'] = util.URL_ORIGIN + '/post_comment?parent_id=' + comment['comment_id'] + "&video_id=" + comments_info['video_id']
        else:
            comment['replies_url'] = util.URL_ORIGIN + '/comments?parent_id=' + comment['comment_id'] + "&video_id=" + comments_info['video_id']

        if num_replies == 0:
            comment['view_replies_text'] = 'Reply'
        elif num_replies == 1:
            comment['view_replies_text'] = '1 reply'
        else:
            comment['view_replies_text'] = str(num_replies) + ' replies'


        if comment['likes'] == 1:
            comment['likes_text'] = '1 like'
        else:
            comment['likes_text'] = str(comment['likes']) + ' likes'

    comments_info['include_avatars'] = settings.enable_comment_avatars
    if comments_info['ctoken'] != '':
        comments_info['more_comments_url'] = util.URL_ORIGIN + '/comments?ctoken=' + comments_info['ctoken']

    comments_info['page_number'] = page_number = str(int(comments_info['offset']/20) + 1)

    if not comments_info['is_replies']:
        comments_info['sort_text'] = 'top' if comments_info['sort'] == 0 else 'newest'


    comments_info['video_url'] = util.URL_ORIGIN + '/watch?v=' + comments_info['video_id']
    comments_info['video_thumbnail'] = '/i.ytimg.com/vi/'+ comments_info['video_id'] + '/mqdefault.jpg'


def video_comments(video_id, sort=0, offset=0, lc='', secret_key=''):
    if settings.enable_comments:
        comments_info = parse_comments_polymer(request_comments(make_comment_ctoken(video_id, sort, offset, lc, secret_key)))
        post_process_comments_info(comments_info)

        post_comment_url = util.URL_ORIGIN + "/post_comment?video_id=" + video_id
        other_sort_url = util.URL_ORIGIN + '/comments?ctoken=' + make_comment_ctoken(video_id, sort=1 - sort, lc=lc)
        other_sort_text = 'Sort by ' + ('newest' if sort == 0 else 'top')
        comments_info['comment_links'] = [('Post comment', post_comment_url), (other_sort_text, other_sort_url)]

        return comments_info

    return {}



@yt_app.route('/comments')
def get_comments_page():
    ctoken = request.args.get('ctoken', '')
    replies = False
    if not ctoken:
        video_id = request.args['video_id']
        parent_id = request.args['parent_id']

        ctoken = comment_replies_ctoken(video_id, parent_id)
        replies = True

    comments_info = parse_comments_polymer(request_comments(ctoken, replies))
    post_process_comments_info(comments_info)

    if not replies:
        other_sort_url = util.URL_ORIGIN + '/comments?ctoken=' + make_comment_ctoken(comments_info['video_id'], sort=1 - comments_info['sort'])
        other_sort_text = 'Sort by ' + ('newest' if comments_info['sort'] == 0 else 'top')
        comments_info['comment_links'] = [(other_sort_text, other_sort_url)]


    comment_posting_box_info = {
        'form_action': '' if replies else util.URL_ORIGIN + '/post_comment',
        'video_id': comments_info['video_id'],
        'accounts': accounts.account_list_data(),
        'include_video_id_input': not replies,
        'replying': replies,
    }

    return flask.render_template('comments_page.html',
        comments_info = comments_info,
        comment_posting_box_info = comment_posting_box_info,
    )