1 files changed, 128 insertions, 0 deletions
diff --git a/youtube/playlist.py b/youtube/playlist.py
new file mode 100644
index 0000000..83d530c
--- /dev/null
+++ b/youtube/playlist.py
@@ -0,0 +1,128 @@
+from youtube import util, yt_data_extract, proto, local_playlist
+from youtube import yt_app
+import settings
+
+import base64
+import urllib
+import json
+import string
+import gevent
+import math
+from flask import request
+import flask
+
+
+def playlist_ctoken(playlist_id, offset, include_shorts=True):
+
+    offset = proto.uint(1, offset)
+    offset = b'PT:' + proto.unpadded_b64encode(offset)
+    offset = proto.string(15, offset)
+    if not include_shorts:
+        offset += proto.string(104, proto.uint(2, 1))
+
+    continuation_info = proto.string(3, proto.percent_b64encode(offset))
+
+    playlist_id = proto.string(2, 'VL' + playlist_id)
+    pointless_nest = proto.string(80226972, playlist_id + continuation_info)
+
+    return base64.urlsafe_b64encode(pointless_nest).decode('ascii')
+
+
+def playlist_first_page(playlist_id, report_text="Retrieved playlist",
+                        use_mobile=False):
+    if use_mobile:
+        url = 'https://m.youtube.com/playlist?list=' + playlist_id + '&pbj=1'
+        content = util.fetch_url(
+            url, util.mobile_xhr_headers,
+            report_text=report_text, debug_name='playlist_first_page'
+        )
+        content = json.loads(content.decode('utf-8'))
+    else:
+        url = 'https://www.youtube.com/playlist?list=' + playlist_id + '&pbj=1'
+        content = util.fetch_url(
+            url, util.desktop_xhr_headers,
+            report_text=report_text, debug_name='playlist_first_page'
+        )
+        content = json.loads(content.decode('utf-8'))
+
+    return content
+
+
+def get_videos(playlist_id, page, include_shorts=True, use_mobile=False,
+               report_text='Retrieved playlist'):
+    # mobile requests return 20 videos per page
+    if use_mobile:
+        page_size = 20
+        headers = util.mobile_xhr_headers
+    # desktop requests return 100 videos per page
+    else:
+        page_size = 100
+        headers = util.desktop_xhr_headers
+
+    url = "https://m.youtube.com/playlist?ctoken="
+    url += playlist_ctoken(playlist_id, (int(page)-1)*page_size,
+                           include_shorts=include_shorts)
+    url += "&pbj=1"
+    content = util.fetch_url(
+        url, headers, report_text=report_text,
+        debug_name='playlist_videos'
+    )
+
+    info = json.loads(content.decode('utf-8'))
+    return info
+
+
+@yt_app.route('/playlist')
+def get_playlist_page():
+    if 'list' not in request.args:
+        abort(400)
+
+    playlist_id = request.args.get('list')
+    page = request.args.get('page', '1')
+
+    if page == '1':
+        first_page_json = playlist_first_page(playlist_id)
+        this_page_json = first_page_json
+    else:
+        tasks = (
+            gevent.spawn(
+                playlist_first_page, playlist_id,
+                report_text="Retrieved playlist info", use_mobile=True
+            ),
+            gevent.spawn(get_videos, playlist_id, page)
+        )
+        gevent.joinall(tasks)
+        util.check_gevent_exceptions(*tasks)
+        first_page_json, this_page_json = tasks[0].value, tasks[1].value
+
+    info = yt_data_extract.extract_playlist_info(this_page_json)
+    if info['error']:
+        return flask.render_template('error.html', error_message=info['error'])
+
+    if page != '1':
+        info['metadata'] = yt_data_extract.extract_playlist_metadata(first_page_json)
+
+    util.prefix_urls(info['metadata'])
+    for item in info.get('items', ()):
+        util.prefix_urls(item)
+        util.add_extra_html_info(item)
+        if 'id' in item:
+            item['thumbnail'] = f"{settings.img_prefix}https://i.ytimg.com/vi/{item['id']}/hqdefault.jpg"
+
+        item['url'] += '&list=' + playlist_id
+        if item['index']:
+            item['url'] += '&index=' + str(item['index'])
+
+    video_count = yt_data_extract.deep_get(info, 'metadata', 'video_count')
+    if video_count is None:
+        video_count = 40
+
+    return flask.render_template(
+        'playlist.html',
+        header_playlist_names=local_playlist.get_playlist_names(),
+        video_list=info.get('items', []),
+        num_pages=math.ceil(video_count/100),
+        parameters_dictionary=request.args,
+
+        **info['metadata']
+    ).encode('utf-8')