[spike] Extract MGID via custom mobile URL

If the conventional MGID detection fails, fall back to searching for the
mobile app's custom URL format.

youtube_dl/extractor/mtv.py

@@ -201,7 +201,7 @@ class MTVServicesInfoExtractor(InfoExtractor):
             [self._get_video_info(item) for item in idoc.findall('.//item')],
             playlist_title=title, playlist_description=description)
 
-    def _extract_mgid(self, webpage):
+    def _extract_mgid(self, webpage, fatal=True):
         try:
             # the url can be http://media.mtvnservices.com/fb/{mgid}.swf
             # or http://media.mtvnservices.com/{mgid}
@@ -221,7 +221,7 @@ class MTVServicesInfoExtractor(InfoExtractor):
             sm4_embed = self._html_search_meta(
                 'sm4:video:embed', webpage, 'sm4 embed', default='')
             mgid = self._search_regex(
-                r'embed/(mgid:.+?)["\'&?/]', sm4_embed, 'mgid')
+                r'embed/(mgid:.+?)["\'&?/]', sm4_embed, 'mgid', fatal=fatal)
         return mgid
 
     def _real_extract(self, url):

youtube_dl/extractor/spike.py

@@ -1,5 +1,7 @@
 from __future__ import unicode_literals
 
+import re
+
 from .mtv import MTVServicesInfoExtractor
 
 
@@ -32,3 +34,12 @@ class SpikeIE(MTVServicesInfoExtractor):
 
     _FEED_URL = 'http://www.spike.com/feeds/mrss/'
     _MOBILE_TEMPLATE = 'http://m.spike.com/videos/video.rbml?id=%s'
+    _CUSTOM_URL_REGEX = re.compile(r'spikenetworkapp://([^/]+/[-a-fA-F0-9]+)')
+
+    def _extract_mgid(self, webpage):
+        mgid = super(SpikeIE, self)._extract_mgid(webpage, fatal=False)
+        if mgid is None:
+            url_parts = self._search_regex(self._CUSTOM_URL_REGEX, webpage, 'episode_id')
+            video_type, episode_id = url_parts.split('/', 1)
+            mgid = 'mgid:arc:{}:spike.com:{}'.format(video_type, episode_id)
+        return mgid