fix error handling, null URLs in templates, and Radio playlist support

- Global error handler: friendly messages for 429, 502, 403, 400
  instead of raw tracebacks. Filter FetchError from Flask logger.
- Fix None URLs in templates: protect href/src in common_elements,
  playlist, watch, and comments templates against None values.
- Radio playlists (RD...): redirect /playlist?list=RD... to
  /watch?v=...&list=RD... since YouTube only supports them in player.
- Wrap player client fallbacks (ios, tv_embedded) in try/catch so
  a failed fallback doesn't crash the whole page.

7 files changed, 86 insertions, 46 deletions

diff --git a/youtube/__init__.py b/youtube/__init__.py
index a8a725d..4859589 100644
--- a/youtube/__init__.py
+++ b/youtube/__init__.py
@@ -5,6 +5,7 @@ from flask import request
 import jinja2
 import settings
 import traceback
+import logging
 import re
 from sys import exc_info
 from flask_babel import Babel
@@ -12,6 +13,15 @@ from flask_babel import Babel
 yt_app = flask.Flask(__name__)
 yt_app.config['TEMPLATES_AUTO_RELOAD'] = True
 yt_app.url_map.strict_slashes = False
+
+# Don't log full tracebacks for handled FetchErrors
+class FetchErrorFilter(logging.Filter):
+    def filter(self, record):
+        if record.exc_info and record.exc_info[0] == util.FetchError:
+            return False
+        return True
+
+yt_app.logger.addFilter(FetchErrorFilter())
 # yt_app.jinja_env.trim_blocks = True
 # yt_app.jinja_env.lstrip_blocks = True
 
@@ -124,49 +134,54 @@ def timestamps(text):
 @yt_app.errorhandler(500)
 def error_page(e):
     slim = request.args.get('slim', False) # whether it was an ajax request
-    if (exc_info()[0] == util.FetchError
-        and exc_info()[1].code == '429'
-        and settings.route_tor
-    ):
-        error_message = ('Error: YouTube blocked the request because the Tor'
-            ' exit node is overutilized. Try getting a new exit node by'
-            ' using the New Identity button in the Tor Browser.')
-        if exc_info()[1].error_message:
-            error_message += '\n\n' + exc_info()[1].error_message
-        if exc_info()[1].ip:
-            error_message += '\n\nExit node IP address: ' + exc_info()[1].ip
-        return flask.render_template('error.html', error_message=error_message, slim=slim), 502
-    elif exc_info()[0] == util.FetchError and exc_info()[1].error_message:
-        # Handle specific error codes with user-friendly messages
-        error_code = exc_info()[1].code
-        error_msg = exc_info()[1].error_message
-
-        if error_code == '400':
-            error_message = (f'Error: Bad Request (400)\n\n{error_msg}\n\n'
-                           'This usually means the URL or parameters are invalid. '
-                           'Try going back and trying a different option.')
+    if exc_info()[0] == util.FetchError:
+        fetch_err = exc_info()[1]
+        error_code = fetch_err.code
+
+        if error_code == '429' and settings.route_tor:
+            error_message = ('Error: YouTube blocked the request because the Tor'
+                ' exit node is overutilized. Try getting a new exit node by'
+                ' using the New Identity button in the Tor Browser.')
+            if fetch_err.error_message:
+                error_message += '\n\n' + fetch_err.error_message
+            if fetch_err.ip:
+                error_message += '\n\nExit node IP address: ' + fetch_err.ip
+            return flask.render_template('error.html', error_message=error_message, slim=slim), 502
+
+        elif error_code == '429':
+            error_message = ('YouTube is temporarily blocking requests from your IP address (429 Too Many Requests).\n\n'
+                'Try:\n'
+                '• Wait a few minutes and refresh\n'
+                '• Enable Tor routing in Settings for automatic IP rotation\n'
+                '• Use a VPN to change your IP address')
+            if fetch_err.ip:
+                error_message += '\n\nYour IP: ' + fetch_err.ip
+            return flask.render_template('error.html', error_message=error_message, slim=slim), 429
+
+        elif error_code == '502' and ('Failed to resolve' in str(fetch_err) or 'Failed to establish' in str(fetch_err)):
+            error_message = ('Could not connect to YouTube.\n\n'
+                'Check your internet connection and try again.')
+            return flask.render_template('error.html', error_message=error_message, slim=slim), 502
+
+        elif error_code == '403':
+            error_message = ('YouTube blocked this request (403 Forbidden).\n\n'
+                'Try enabling Tor routing in Settings.')
+            return flask.render_template('error.html', error_message=error_message, slim=slim), 403
+
         elif error_code == '404':
             error_message = 'Error: The page you are looking for isn\'t here.'
+            return flask.render_template('error.html', error_code=error_code,
+                                         error_message=error_message, slim=slim), 404
+
         else:
-            error_message = f'Error: {error_code} - {error_msg}'
-
-        return (flask.render_template(
-                    'error.html',
-                    error_message=error_message,
-                    slim=slim
-                ), 502)
-    elif (exc_info()[0] == util.FetchError
-        and exc_info()[1].code == '404'
-    ):
-        error_message = ('Error: The page you are looking for isn\'t here.')
-        return flask.render_template('error.html',
-                                     error_code=exc_info()[1].code,
-                                     error_message=error_message,
-                                     slim=slim), 404
+            # Catch-all for any other FetchError (400, etc.)
+            error_message = f'Error communicating with YouTube ({error_code}).'
+            if fetch_err.error_message:
+                error_message += '\n\n' + fetch_err.error_message
+            return flask.render_template('error.html', error_message=error_message, slim=slim), 502
+
     return flask.render_template('error.html', traceback=traceback.format_exc(),
-                                 error_code=exc_info()[1].code,
                                  slim=slim), 500
-    # return flask.render_template('error.html', traceback=traceback.format_exc(), slim=slim), 500
 
 
 font_choices = {
diff --git a/youtube/playlist.py b/youtube/playlist.py
index bedf2d2..c7e0410 100644
--- a/youtube/playlist.py
+++ b/youtube/playlist.py
@@ -78,6 +78,15 @@ def get_playlist_page():
         abort(400)
 
     playlist_id = request.args.get('list')
+
+    # Radio/Mix playlists (RD...) only work as watch page, not playlist page
+    if playlist_id.startswith('RD'):
+        first_video_id = playlist_id[2:]  # video ID after 'RD' prefix
+        return flask.redirect(
+            util.URL_ORIGIN + '/watch?v=' + first_video_id + '&list=' + playlist_id,
+            302
+        )
+
     page = request.args.get('page', '1')
 
     if page == '1':
diff --git a/youtube/templates/comments.html b/youtube/templates/comments.html
index 7bd75e5..4728a0a 100644
--- a/youtube/templates/comments.html
+++ b/youtube/templates/comments.html
@@ -3,13 +3,13 @@
 {% macro render_comment(comment, include_avatar, timestamp_links=False) %}
     <div class="comment-container">
         <div class="comment">
-            <a class="author-avatar" href="{{ comment['author_url'] }}" title="{{ comment['author'] }}">
+            <a class="author-avatar" href="{{ comment['author_url'] or '#' }}" title="{{ comment['author'] }}">
                 {% if include_avatar %}
                     <img class="author-avatar-img" alt="{{ comment['author'] }}" src="{{ comment['author_avatar'] }}">
                 {% endif %}
             </a>
             <address class="author-name">
-                <a class="author" href="{{ comment['author_url'] }}" title="{{ comment['author'] }}">{{ comment['author'] }}</a>
+                <a class="author" href="{{ comment['author_url'] or '#' }}" title="{{ comment['author'] }}">{{ comment['author'] }}</a>
             </address>
             <a class="permalink" href="{{ comment['permalink'] }}" title="permalink">
                 <span>{{ comment['time_published'] }}</span>
diff --git a/youtube/templates/common_elements.html b/youtube/templates/common_elements.html
index bd43761..5b72063 100644
--- a/youtube/templates/common_elements.html
+++ b/youtube/templates/common_elements.html
@@ -20,7 +20,7 @@
             {{ info['error'] }}
         {% else %}
             <div class="item-video {{ info['type'] + '-item' }}">
-                <a class="thumbnail-box" href="{{ info['url'] }}" title="{{ info['title'] }}">
+                <a class="thumbnail-box" href="{{ info['url'] or '#' }}" title="{{ info['title'] }}">
                     <div class="thumbnail {% if info['type'] == 'channel' %} channel {% endif %}">
                         {% if lazy_load %}
                             <img class="thumbnail-img lazy" alt="&#x20;" data-src="{{ info['thumbnail'] }}" onerror="thumbnail_fallback(this)">
@@ -35,7 +35,7 @@
                         {% endif %}
                     </div>
                 </a>
-                <h4 class="title"><a href="{{ info['url'] }}" title="{{ info['title'] }}">{{ info['title'] }}</a></h4>
+                <h4 class="title"><a href="{{ info['url'] or '#' }}" title="{{ info['title'] }}">{{ info['title'] }}</a></h4>
 
                 {% if include_author %}
                     {% set author_description = info['author'] %}
diff --git a/youtube/templates/playlist.html b/youtube/templates/playlist.html
index 994523e..dc9c37a 100644
--- a/youtube/templates/playlist.html
+++ b/youtube/templates/playlist.html
@@ -10,11 +10,17 @@
 
     <div class="playlist-metadata">
         <div class="author">
+            {% if thumbnail %}
             <img alt="{{ title }}" src="{{ thumbnail }}">
+            {% endif %}
             <h2>{{ title }}</h2>
         </div>
         <div class="summary">
+            {% if author_url %}
             <a class="playlist-author" href="{{ author_url }}">{{ author }}</a>
+            {% else %}
+            <span class="playlist-author">{{ author }}</span>
+            {% endif %}
         </div>
         <div class="playlist-stats">
             <div>{{ video_count|commatize }} videos</div>
diff --git a/youtube/templates/watch.html b/youtube/templates/watch.html
index 5ff31cb..d62884f 100644
--- a/youtube/templates/watch.html
+++ b/youtube/templates/watch.html
@@ -172,7 +172,11 @@
                             {% else %}
                                 <li>{{ playlist['current_index']+1 }}/{{ playlist['video_count'] }}</li>
                             {% endif %}
+                            {% if playlist['author_url'] %}
                             <li><a href="{{ playlist['author_url'] }}" title="{{ playlist['author'] }}">{{ playlist['author'] }}</a></li>
+                            {% elif playlist['author'] %}
+                            <li>{{ playlist['author'] }}</li>
+                            {% endif %}
                         </ul>
                     </div>
                     <nav class="playlist-videos">
diff --git a/youtube/watch.py b/youtube/watch.py
index 2fbc1fc..360fbc9 100644
--- a/youtube/watch.py
+++ b/youtube/watch.py
@@ -431,14 +431,20 @@ def extract_info(video_id, use_invidious, playlist_id=None, index=None):
     # Fallback to 'ios' if no valid URLs are found
     if not info.get('formats') or info.get('player_urls_missing'):
         print(f"No URLs found in '{primary_client}', attempting with '{fallback_client}'.")
-        player_response = fetch_player_response(fallback_client, video_id) or {}
-        yt_data_extract.update_with_new_urls(info, player_response)
+        try:
+            player_response = fetch_player_response(fallback_client, video_id) or {}
+            yt_data_extract.update_with_new_urls(info, player_response)
+        except util.FetchError as e:
+            print(f"Fallback '{fallback_client}' failed: {e}")
 
     # Final attempt with 'tv_embedded' if there are still no URLs
     if not info.get('formats') or info.get('player_urls_missing'):
         print(f"No URLs found in '{fallback_client}', attempting with '{last_resort_client}'")
-        player_response = fetch_player_response(last_resort_client, video_id) or {}
-        yt_data_extract.update_with_new_urls(info, player_response)
+        try:
+            player_response = fetch_player_response(last_resort_client, video_id) or {}
+            yt_data_extract.update_with_new_urls(info, player_response)
+        except util.FetchError as e:
+            print(f"Fallback '{last_resort_client}' failed: {e}")
 
     # signature decryption
     if info.get('formats'):