From 6d74ea6802998f0db0075b1778f830d49be019e8 Mon Sep 17 00:00:00 2001
From: girst <tobi@isticktoit.net>
Date: Sat, 29 Apr 2023 12:44:11 +0000
Subject: [PATCH] use resolve_url endpoint for channel canonicalisation

one less seperate place we call into youtube's frontend apis

we now support:
  - /channel/ucid
  - /c/vanity
  - /user/username
  - /@handle
  - /brandname

according to https://support.google.com/youtube/answer/6180214?hl=en
vanity urls and usernames are legacy, brand urls aren't documented at
all.
---
 app/browse/__init__.py | 15 ++++++++-------
 app/browse/lib.py      | 26 ++++++++------------------
 2 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/app/browse/__init__.py b/app/browse/__init__.py
index 6a6b1aa..4673dd6 100644
--- a/app/browse/__init__.py
+++ b/app/browse/__init__.py
@@ -118,6 +118,7 @@ def channel(channel_id, subpage="videos"):
         is_subscribed=is_subscribed,
         continuation=continuation)
 
+@frontend.route('/<user>/<subpage>')
 @frontend.route('/user/<user>/')
 @frontend.route('/user/<user>/<subpage>')
 @frontend.route('/c/<user>/')
@@ -127,15 +128,17 @@ def channel_redirect(user, subpage=None):
     The browse_ajax 'API' needs the UCID.
     """
 
-    typ = request.path.split("/")[1] # 'c' or 'user'
-
     # inverse of the test in /channel/:
     if re.match(r"(UC[A-Za-z0-9_-]{22})", user):
         return redirect(url_for('.channel', channel_id=user))
 
-    channel_id = canonicalize_channel(user, typ)
+    if subpage not in (None, "home", "videos", "shorts", "streams", "playlists", "community", "channels", "about"):
+        raise NotFound("not a valid channel subpage")
+
+    channel_id = canonicalize_channel(request.path)
     if not channel_id:
-        raise NotFound("channel appears to not exist")
+        raise NotFound("channel does not exist")
+
     return redirect(
         url_for('.channel', channel_id=channel_id, subpage=subpage), 308
     )
@@ -177,9 +180,7 @@ def plain_user_or_video(something):
         # prevent a lot of false-positives (and reduce youtube api calls)
         raise NotFound
 
-    # possible channel names: need to distinguish /name from /@name
-    typ = "c" if something[0] != "@" else ""
-    channel_id = canonicalize_channel(something, typ)
+    channel_id = canonicalize_channel(something) # /vanity or /@handle
     if channel_id:
         return redirect(url_for('.channel', channel_id=channel_id))
     elif re.match(r"^[-_0-9A-Za-z]{11}$", something): # looks like a video id
diff --git a/app/browse/lib.py b/app/browse/lib.py
index 5d46b05..a4becf7 100644
--- a/app/browse/lib.py
+++ b/app/browse/lib.py
@@ -12,7 +12,7 @@ def fetch_ajax(endpoint, **kwargs):
     today = datetime.now(timezone.utc).strftime("%Y%m%d")
 
     # TODO: this is not cached any more! -> https://github.com/reclosedev/requests-cache/issues/154
-    # Note: this 'innertube' API key exists since at least 2015: https://stackoverflow.com/q/33511165
+    # TODO: replace host with youtubei.googleapis.com (used by android)?
     r = requests.post(f"https://www.youtube.com/youtubei/v1/{endpoint}?key=AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8", json={
         **kwargs,
         'context': {'client': {
@@ -28,24 +28,14 @@ def fetch_ajax(endpoint, **kwargs):
 
     return r.json()
 
-def canonicalize_channel(name, typ="c"):
-    if re.fullmatch(r"(UC[A-Za-z0-9_-]{22})", name):
-        return name
+def canonicalize_channel(path):
+    if re.fullmatch(r"(UC[A-Za-z0-9_-]{22})", path):
+        return path
 
-    # get UCID of /c/ (vanity URLs):
-    today = datetime.now(timezone.utc).strftime("%Y%m%d")
-    typ += "/" if typ != "@" else ""
-    r = requests.get(f'https://www.youtube.com/{typ}{name}/about?pbj=1&hl=en_US', headers={
-        'x-youtube-client-name': '1',
-        'x-youtube-client-version': f'2.{today}.01.01', # see fetch_searchresults()
-    })
-    try:
-        return r.json()[1]['response']['metadata']['channelMetadataRenderer']['rssUrl'].split("=")[1]
-    except:
-        pass
-
-    # unable to extract:
-    return None
+    # Note: for /watch, append query string, then return .endpoint.watchEndpoint.videoId
+    resolved = fetch_ajax("navigation/resolve_url", url=f"https://www.youtube.com/{path}")
+    channel_id = resolved.get('endpoint',{}).get('browseEndpoint',{}).get('browseId')
+    return channel_id
 
 def find_and_parse_error(result):
     error_obj = (
-- 
2.39.3