refactor: replace string concatenations with f-strings

youtube/channel.py

@@ -253,7 +253,7 @@ def get_channel_tab(channel_id, page="1", sort=3, tab='videos', view=1,
     # For now it seems to be constant for the API endpoint, not dependent
     # on the browsing session or channel
     key = 'AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8'
-    url = 'https://www.youtube.com/youtubei/v1/browse?key=' + key
+    url = f'https://www.youtube.com/youtubei/v1/browse?key={key}'
 
     data = {
         'context': {
@@ -285,8 +285,8 @@ def get_number_of_videos_channel(channel_id):
         return 1000
 
     # Uploads playlist
-    playlist_id = 'UU' + channel_id[2:]
-    url = 'https://m.youtube.com/playlist?list=' + playlist_id + '&pbj=1'
+    playlist_id = f'UU{channel_id[2:]}'
+    url = f'https://m.youtube.com/playlist?list={playlist_id}&pbj=1'
 
     try:
         response = util.fetch_url(url, headers_mobile,
@@ -328,7 +328,7 @@ def get_channel_id(base_url):
     # method that gives the smallest possible response at ~4 kb
     # needs to be as fast as possible
     base_url = base_url.replace('https://www', 'https://m') # avoid redirect
-    response = util.fetch_url(base_url + '/about?pbj=1', headers_mobile,
+    response = util.fetch_url(f'{base_url}/about?pbj=1', headers_mobile,
         debug_name='get_channel_id', report_text='Got channel id').decode('utf-8')
     match = channel_id_re.search(response)
     if match:
@@ -372,7 +372,7 @@ def get_channel_search_json(channel_id, query, page):
     ctoken = base64.urlsafe_b64encode(proto.nested(80226972, ctoken)).decode('ascii')
 
     key = 'AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8'
-    url = 'https://www.youtube.com/youtubei/v1/browse?key=' + key
+    url = f'https://www.youtube.com/youtubei/v1/browse?key={key}'
 
     data = {
         'context': {
@@ -414,18 +414,18 @@ def post_process_channel_info(info):
 
 def get_channel_first_page(base_url=None, tab='videos', channel_id=None, sort=None):
     if channel_id:
-        base_url = 'https://www.youtube.com/channel/' + channel_id
+        base_url = f'https://www.youtube.com/channel/{channel_id}'
 
     # Build URL with sort parameter
     # YouTube URL sort params: p=popular, dd=newest, lad=newest no shorts
     # Note: 'da' (oldest) was removed by YouTube in January 2026
-    url = base_url + '/' + tab + '?pbj=1&view=0'
+    url = f'{base_url}/{tab}?pbj=1&view=0'
     if sort:
         # Map sort values to YouTube's URL parameter values
         sort_map = {'3': 'dd', '4': 'lad'}
-        url += '&sort=' + sort_map.get(sort, 'dd')
+        url += f'&sort={sort_map.get(sort, "dd")}'
 
-    return util.fetch_url(url, headers_desktop, debug_name='gen_channel_' + tab)
+    return util.fetch_url(url, headers_desktop, debug_name=f'gen_channel_{tab}')
 
 
 playlist_sort_codes = {'2': "da", '3': "dd", '4': "lad"}
@@ -462,7 +462,7 @@ def get_channel_page_general_url(base_url, tab, request, channel_id=None):
         if page_number == 1:
             tasks = (
                 gevent.spawn(playlist.playlist_first_page,
-                             'UU' + channel_id[2:],
+                             f'UU{channel_id[2:]}',
                              report_text='Retrieved channel videos'),
                 gevent.spawn(get_metadata, channel_id),
             )
@@ -477,11 +477,11 @@ def get_channel_page_general_url(base_url, tab, request, channel_id=None):
                 set_cached_number_of_videos(channel_id, number_of_videos)
         else:
             tasks = (
-                gevent.spawn(playlist.get_videos, 'UU' + channel_id[2:],
+                gevent.spawn(playlist.get_videos, f'UU{channel_id[2:]}',
                              page_number, include_shorts=True),
                 gevent.spawn(get_metadata, channel_id),
                 gevent.spawn(get_number_of_videos_channel, channel_id),
-                gevent.spawn(playlist.playlist_first_page, 'UU' + channel_id[2:],
+                gevent.spawn(playlist.playlist_first_page, f'UU{channel_id[2:]}',
                              report_text='Retrieved channel video count'),
             )
             gevent.joinall(tasks)
@@ -567,10 +567,10 @@ def get_channel_page_general_url(base_url, tab, request, channel_id=None):
     elif tab == 'search' and channel_id:
         polymer_json = get_channel_search_json(channel_id, query, page_number)
     elif tab == 'search':
-        url = base_url + '/search?pbj=1&query=' + urllib.parse.quote(query, safe='')
+        url = f'{base_url}/search?pbj=1&query={urllib.parse.quote(query, safe="")}'
         polymer_json = util.fetch_url(url, headers_desktop, debug_name='gen_channel_search')
     elif tab != 'videos':
-        flask.abort(404, 'Unknown channel tab: ' + tab)
+        flask.abort(404, f'Unknown channel tab: {tab}')
 
     if polymer_json is not None and info is None:
         info = yt_data_extract.extract_channel_info(
@@ -583,7 +583,7 @@ def get_channel_page_general_url(base_url, tab, request, channel_id=None):
         return flask.render_template('error.html', error_message=info['error'])
 
     if channel_id:
-        info['channel_url'] = 'https://www.youtube.com/channel/' + channel_id
+        info['channel_url'] = f'https://www.youtube.com/channel/{channel_id}'
         info['channel_id'] = channel_id
     else:
         channel_id = info['channel_id']
@@ -663,22 +663,22 @@ def get_channel_page_general_url(base_url, tab, request, channel_id=None):
 @yt_app.route('/channel/<channel_id>/')
 @yt_app.route('/channel/<channel_id>/<tab>')
 def get_channel_page(channel_id, tab='videos'):
-    return get_channel_page_general_url('https://www.youtube.com/channel/' + channel_id, tab, request, channel_id)
+    return get_channel_page_general_url(f'https://www.youtube.com/channel/{channel_id}', tab, request, channel_id)
 
 
 @yt_app.route('/user/<username>/')
 @yt_app.route('/user/<username>/<tab>')
 def get_user_page(username, tab='videos'):
-    return get_channel_page_general_url('https://www.youtube.com/user/' + username, tab, request)
+    return get_channel_page_general_url(f'https://www.youtube.com/user/{username}', tab, request)
 
 
 @yt_app.route('/c/<custom>/')
 @yt_app.route('/c/<custom>/<tab>')
 def get_custom_c_page(custom, tab='videos'):
-    return get_channel_page_general_url('https://www.youtube.com/c/' + custom, tab, request)
+    return get_channel_page_general_url(f'https://www.youtube.com/c/{custom}', tab, request)
 
 
 @yt_app.route('/<custom>')
 @yt_app.route('/<custom>/<tab>')
 def get_toplevel_custom_page(custom, tab='videos'):
-    return get_channel_page_general_url('https://www.youtube.com/' + custom, tab, request)
+    return get_channel_page_general_url(f'https://www.youtube.com/{custom}', tab, request)