Add `--force-generic-extractor`

For some extractors that are hard to workout a good _VALID_URL we use very vague and unrestrictive ones,
e.g. just allowing anything after hostname and capturing part of URL as id.
If some of these extractors happen to have an video embed of some different hoster or platform
and this scenario was not handled in extractor itself we end up with inability to download this embed
until extractor is fixed to support embed of this kind.
Forcing downloader to use the generic extractor can be a neat temporary solution for this problem.
Example: FiveTV extractor with Tvigle embed - http://www.5-tv.ru/rabota/broadcasts/48/

youtube_dl/YoutubeDL.py

@@ -139,6 +139,7 @@ class YoutubeDL(object):
     outtmpl:           Template for output names.
     restrictfilenames: Do not allow "&" and spaces in file names
     ignoreerrors:      Do not stop on download errors.
+    force_generic_extractor: Force downloader to use the generic extractor
     nooverwrites:      Prevent overwriting files.
     playliststart:     Playlist item to start at.
     playlistend:       Playlist item to end at.
@@ -282,6 +283,7 @@ class YoutubeDL(object):
         self._num_downloads = 0
         self._screen_file = [sys.stdout, sys.stderr][params.get('logtostderr', False)]
         self._err_file = sys.stderr
+        self._force_generic_extractor_required = params.get('force_generic_extractor', False)
         self.params = params
         self.cache = Cache(self)
 
@@ -633,6 +635,10 @@ class YoutubeDL(object):
         extra_info is a dict containing the extra values to add to each result
         '''
 
+        if not ie_key and self._force_generic_extractor_required:
+            self._force_generic_extractor_required = False
+            ie_key = 'Generic'
+
         if ie_key:
             ies = [self.get_info_extractor(ie_key)]
         else:

youtube_dl/__init__.py

@@ -293,6 +293,7 @@ def _real_main(argv=None):
         'autonumber_size': opts.autonumber_size,
         'restrictfilenames': opts.restrictfilenames,
         'ignoreerrors': opts.ignoreerrors,
+        'force_generic_extractor': opts.force_generic_extractor,
         'ratelimit': opts.ratelimit,
         'nooverwrites': opts.nooverwrites,
         'retries': opts_retries,

youtube_dl/extractor/generic.py

@@ -977,7 +977,9 @@ class GenericIE(InfoExtractor):
                 'upload_date': upload_date,
             }
 
-        if not self._downloader.params.get('test', False) and not is_intentional:
+        if (not self._downloader.params.get('test', False) and
+                not is_intentional and
+                not self._downloader.params.get('force_generic_extractor', False)):
             self._downloader.report_warning('Falling back on generic information extractor.')
 
         if not full_response:

youtube_dl/options.py

@@ -150,6 +150,10 @@ def parseOpts(overrideArguments=None):
         '--extractor-descriptions',
         action='store_true', dest='list_extractor_descriptions', default=False,
         help='Output descriptions of all supported extractors')
+    general.add_option(
+        '--force-generic-extractor',
+        action='store_true', dest='force_generic_extractor', default=False,
+        help='Force extraction to use the generic extractor')
     general.add_option(
         '--default-search',
         dest='default_search', metavar='PREFIX',