better handle IDs in video backends, enhance user interaction

weboob/backend.py

@@ -115,3 +115,36 @@ class BaseBackend(object):
             if isinstance(self, c):
                 return True
         return False
+
+
+def check_domain(domain):
+    def wrapper(func):
+        def inner(self, *args, **kwargs):
+            url = args[0]
+            if isinstance(url, (str,unicode)) and not url.isdigit() and u'youjizz.com' not in url:
+                return None
+            return func(self, *args, **kwargs)
+        return inner
+    return wrapper
+
+
+def id2url(domain, id2url):
+    def wrapper(func):
+        def inner(self, *args, **kwargs):
+            arg = unicode(args[0])
+            if arg.startswith('http://'):
+                if domain in arg:
+                    url = arg
+                else:
+                    return None
+            else:
+                provider, _id = arg.split(':')
+                if provider == self.name:
+                    url = id2url(_id)
+                else:
+                    return None
+            new_args = [url]
+            new_args.extend(args[1:])
+            return func(self, *new_args, **kwargs)
+        return inner
+    return wrapper