Support more YouTube URLs

The regular expression is also more strict, yet accepts the
youtu.be short URLs and user page URLs.

weboob/backends/youtube/backend.py

@@ -45,7 +45,7 @@ class YoutubeBackend(BaseBackend, ICapVideo):
     LICENSE = 'AGPLv3+'
     BROWSER = YoutubeBrowser
 
-    URL_RE = re.compile(r'https?://.*youtube.com/watch\?v=(.*)')
+    URL_RE = re.compile(r'^https?://(?:\w*\.?youtube\.com/watch\?v=|youtu\.be\/|\w*\.?youtube\.com\/user\/\w+#p\/u\/\d+\/)(.*)$')
     AVAILABLE_FORMATS = [38, 37, 22, 45, 35, 34, 43, 18, 6, 5, 17, 13]
     FORMAT_EXTENSIONS = {
         13: '3gp',

weboob/backends/youtube/test.py

@@ -29,4 +29,5 @@ class YoutubeTest(BackendTest):
         v = l[0]
         self.backend.fillobj(v, ('url',))
         self.assertTrue(v.url and v.url.startswith('http://'), 'URL for video "%s" not found: %s' % (v.id, v.url))
+        assert self.backend.get_video(v.shorturl)
         self.backend.browser.openurl(v.url)

weboob/backends/youtube/video.py

@@ -28,3 +28,8 @@ class YoutubeVideo(BaseVideo):
     @classmethod
     def id2url(cls, _id):
         return 'http://www.youtube.com/watch?v=%s' % _id
+
+    def _get_shorturl(self):
+        return 'http://youtu.be/%s' % self.id
+
+    shorturl = property(_get_shorturl)