Extraction: Proper error handling for terminated or non-existant channels

youtube/channel.py

@@ -186,6 +186,8 @@ def get_channel_page(channel_id, tab='videos'):
 
 
     info = yt_data_extract.extract_channel_info(json.loads(polymer_json), tab)
+    if info['errors']:
+        return flask.render_template('error.html', error_message = '\n'.join(info['errors']))
     post_process_channel_info(info)
     if tab in ('videos', 'search'):
         info['number_of_videos'] = number_of_videos
@@ -226,6 +228,9 @@ def get_channel_page_general_url(base_url, tab, request):
 
 
     info = yt_data_extract.extract_channel_info(json.loads(polymer_json), tab)
+    if info['errors']:
+        return flask.render_template('error.html', error_message = '\n'.join(info['errors']))
+
     post_process_channel_info(info)
     if tab in ('videos', 'search'):
         info['number_of_videos'] = 1000

youtube/subscriptions.py

@@ -455,7 +455,12 @@ def _get_upstream_videos(channel_id):
         print('Failed to read atoma feed for ' + channel_status_name)
         traceback.print_exc()
 
-    videos = yt_data_extract.extract_channel_info(json.loads(channel_tab), 'videos')['items']
+    channel_info = yt_data_extract.extract_channel_info(json.loads(channel_tab), 'videos')
+    if channel_info['errors']:
+        print('Error checking channel ' + channel_status_name + ': ' + ', '.join(channel_info['errors']))
+        return
+
+    videos = channel_info['items']
     for i, video_item in enumerate(videos):
         if 'description' not in video_item:
             video_item['description'] = ''

youtube/yt_data_extract.py

@@ -281,6 +281,7 @@ def parse_info_prepare_for_html(renderer, additional_info={}):
 
 
 def extract_channel_info(polymer_json, tab):
+    info = {'errors': []}
     response = polymer_json[1]['response']
     try:
         microformat = response['microformat']['microformatDataRenderer']
@@ -289,18 +290,18 @@ def extract_channel_info(polymer_json, tab):
     # example terminated channel: https://www.youtube.com/channel/UCnKJeK_r90jDdIuzHXC0Org
     except KeyError:
         if 'alerts' in response and len(response['alerts']) > 0:
-            result = ''
             for alert in response['alerts']:
-                result += alert['alertRenderer']['text']['simpleText'] + '\n'
-            flask.abort(200, result)
+                info['errors'].append(alert['alertRenderer']['text']['simpleText'])
+            return info
         elif 'errors' in response['responseContext']:
             for error in response['responseContext']['errors']['error']:
                 if error['code'] == 'INVALID_VALUE' and error['location'] == 'browse_id':
-                    flask.abort(404, 'This channel does not exist')
-        raise
+                    info['errors'].append('This channel does not exist')
+                    return info
+        info['errors'].append('Failure getting microformat')
+        return info
 
 
-    info = {}
     info['current_tab'] = tab