[shared] Respect redirect URL (Closes #10170)

youtube_dl/extractor/shared.py

@@ -37,15 +37,17 @@ class SharedIE(InfoExtractor):
 
     def _real_extract(self, url):
         video_id = self._match_id(url)
-        webpage = self._download_webpage(url, video_id)
+
+        webpage, urlh = self._download_webpage_handle(url, video_id)
 
         if '>File does not exist<' in webpage:
             raise ExtractorError(
                 'Video %s does not exist' % video_id, expected=True)
 
         download_form = self._hidden_inputs(webpage)
+
         request = sanitized_Request(
-            url, urlencode_postdata(download_form))
+            urlh.geturl(), urlencode_postdata(download_form))
         request.add_header('Content-Type', 'application/x-www-form-urlencoded')
 
         video_page = self._download_webpage(