Update mailru.py

youtube_dl/extractor/mailru.py

@@ -128,8 +128,12 @@ class MailRuIE(InfoExtractor):
                 'http://api.video.mail.ru/videos/%s.json?new=1' % video_id,
                 video_id, 'Downloading video JSON')
 
+        headers = {}
+
         video_key = self._get_cookies('https://my.mail.ru').get('video_key')
-        key = 'video_key=%s' % video_key.value
+        if video_key:
+            headers['Cookie'] = 'video_key=%s' % video_key.value
+
         formats = []
         for f in video_data['videos']:
             video_url = f.get('url')
@@ -142,9 +146,7 @@ class MailRuIE(InfoExtractor):
                 'url': video_url,
                 'format_id': format_id,
                 'height': height,
-                'http_headers': {
-                    'Cookie': key,
-                },
+                'http_headers': headers,
             })
         self._sort_formats(formats)