Avoid dangerous accesses, more coding conventions

yt_dlp/extractor/heinetworktv.py

@@ -12,6 +12,7 @@ from ..utils import (
     get_element_html_by_id,
     get_element_text_and_html_by_tag,
     get_elements_html_by_class,
+    int_or_none,
     unified_strdate,
 )
 
@@ -57,7 +58,10 @@ class HEINetworkTVIE(InfoExtractor):
 
     def _real_extract(self, url):
         parts = urllib.parse.urlparse(url).path.split('/')
-        # remove empty parts; get last element
+        # Remove empty parts; get last element.
+        # This isn't necessarily a site-wide unique ID (we'll get that from the
+        # page content), but it at least gives us something unique-ish to pass
+        # to `_download_webpage`.
         item_id = next(filter(None, reversed(parts)))
 
         webpage = self._download_webpage(url, item_id)
@@ -69,74 +73,70 @@ class HEINetworkTVIE(InfoExtractor):
             return self._extract_single_video(webpage, url)
 
     def _extract_collection(self, webpage, url):
-        grid = get_element_html_by_class('group/collection', webpage)
-        linksHtml = get_elements_html_by_class('group/thumb', grid)
-        urls = [extract_attributes(html)['href'] for html in linksHtml]
+        if grid := get_element_html_by_class('group/collection', webpage):
+            if linksHtml := get_elements_html_by_class('group/thumb', grid):
+                urls = [extract_attributes(html).get('href') for html in linksHtml]
 
-        return self.playlist_from_matches(
-            urls,
-            ie=HEINetworkTVIE,
-            playlist_id=self._path_components(url)[-1],
-            playlist_title=self._breadcrumbs(webpage)[-1],
-        )
+                return self.playlist_from_matches(
+                    urls,
+                    ie=HEINetworkTVIE,
+                    playlist_id=self._path_components(url)[-1],
+                    playlist_title=self._breadcrumbs(webpage)[-1],
+                )
 
     def _extract_season_name_and_number(self, webpage):
-        bc = self._breadcrumbs(webpage)
-        if len(bc) != 2:
-            return None, None
-        season_name = bc[-1]
-        season_number_match = re.match(r'Season (\d+)', season_name)
-        if not season_number_match:
-            return season_name, None
-        return season_name, int(season_number_match.group(1))
+        # expected breadcrumbs to be [series, season] for an episode page
+        if (bc := self._breadcrumbs(webpage)) and len(bc) == 2:
+            season_name = bc[-1]
+            season_number_match = re.match(r'Season (?P<season>\d+)', season_name)
+            if not season_number_match:
+                return season_name, None
+            return season_name, int_or_none(season_number_match.group('season'))
+        return None, None
 
     def _extract_series_name(self, webpage):
-        bc = self._breadcrumbs(webpage)
-        if len(bc) < 1:
-            return None
-        return bc[0]
+        if (bc := self._breadcrumbs(webpage)) and len(bc) >= 1:
+            return bc[0]
 
     def _path_components(self, url):
         return [p for p in urllib.parse.urlparse(url).path.split('/') if p]
 
     def _extract_video_id(self, webpage):
         _text, html = get_element_text_and_html_by_tag('hei-video', webpage)
+        if html is None:
+            return None
         attrs = extract_attributes(html)
-        return attrs['data-episode-id']
+        return attrs.get('data-episode-id')
 
     def _clean_episode_title(self, video_title):
-        match = re.match(r'\d+\s+(?P<title>.+)', video_title)
-        if match:
+        # ex: 1301 Episode Title
+        if match := re.match(r'\d+\s+(?P<title>.+)', video_title):
             return match.group('title')
-        return None
 
     def _episode_number(self, video_title, season_number):
         if season_number is None:
             return None
+        # ex: 1301 -> season 13, episode 01
         match = re.match(fr'{re.escape(str(season_number))}(?P<episode_no>\d+)', video_title)
         if match:
-            return int(match.group('episode_no'))
-        return None
+            return int_or_none(match.group('episode_no'))
 
     def _extract_single_video(self, webpage, url):
-        path_components = self._path_components(url)
         video_id = self._extract_video_id(webpage)
-        video_src = self._extract_video_src(webpage)
-        formats, _subs = self._extract_m3u8_formats_and_subtitles(video_src, video_id)
-        air_date = self._air_date(webpage)
+        formats, _subs = self._extract_m3u8_formats_and_subtitles(
+            self._extract_video_src(webpage), video_id)
         season, season_number = self._extract_season_name_and_number(webpage)
-        series = self._extract_series_name(webpage)
         video_title = self._extract_video_title(webpage)
 
         return {
             'id': video_id,
             'title': video_title,
             'formats': formats,
-            'release_date': air_date,
+            'release_date': self._air_date(webpage),
             'season': season,
             'season_number': season_number,
-            'season_id': path_components[-2],
-            'series': series,
+            'season_id': self._path_components(url)[-2],
+            'series': self._extract_series_name(webpage),
             'episode': self._clean_episode_title(video_title),
             'episode_number': self._episode_number(video_title, season_number),
         }
@@ -150,26 +150,28 @@ class HEINetworkTVIE(InfoExtractor):
         return get_element_by_class('group/collection', webpage) is not None
 
     def _breadcrumbs(self, webpage):
-        breadcrumb_container = get_element_html_by_class('breadcrumbs', webpage)
-        root = ElementTree.fromstring(breadcrumb_container)
-        return [''.join(e.itertext()).strip() for e in root.findall('.//li')]
+        if breadcrumb_container := get_element_html_by_class('breadcrumbs', webpage):
+            root = ElementTree.fromstring(breadcrumb_container)
+            return [''.join(e.itertext()).strip() for e in root.findall('.//li')]
 
     # Single-video helpers
 
     def _extract_video_src(self, webpage):
         _, html = get_element_text_and_html_by_tag('castable-video', webpage)
+        if html is None:
+            return None
         attrs = extract_attributes(html)
-        return attrs['src']
+        return attrs.get('src')
 
     def _extract_video_title(self, webpage):
         _, mux_video = get_element_text_and_html_by_tag('mux-video', webpage)
-        attrs = extract_attributes(mux_video)
-        if 'metadata-video-title' not in attrs:
+        if mux_video is None:
             return None
-        return attrs['metadata-video-title']
+        attrs = extract_attributes(mux_video)
+        return attrs.get('metadata-video-title')
 
     def _air_date(self, webpage):
-        episode_info_container = get_element_html_by_id('hei-episode-title', webpage)
-        release_date_str = get_element_by_class('text-sm', episode_info_container)
-        matches = re.match(r'\s+Air Date: (?P<date>[\w/]+)', release_date_str)
-        return unified_strdate(matches.group('date'), day_first=False)
+        if episode_info_container := get_element_html_by_id('hei-episode-title', webpage):
+            if release_date_str := get_element_by_class('text-sm', episode_info_container):
+                if matches := re.match(r'\s+Air Date: (?P<date>[\w/]+)', release_date_str):
+                    return unified_strdate(matches.group('date'), day_first=False)