[vbox7:generic] Add support for vbox7 embeds

youtube_dl/extractor/vbox7.py

@@ -1,6 +1,8 @@
 # encoding: utf-8
 from __future__ import unicode_literals
 
+import re
+
 from .common import InfoExtractor
 from ..utils import urlencode_postdata
 
@@ -29,6 +31,14 @@ class Vbox7IE(InfoExtractor):
         'only_matching': True,
     }]
 
+    @staticmethod
+    def _extract_url(webpage):
+        mobj = re.search(
+            '<iframe[^>]+src=(?P<q>["\'])(?P<url>(?:https?:)?//vbox7\.com/emb/external\.php.+?)(?P=q)',
+            webpage)
+        if mobj:
+            return mobj.group('url')
+
     def _real_extract(self, url):
         video_id = self._match_id(url)