Add show_if and hide_if methods for routes and APIs, as well as proper comparison of feature values

endpoints/api/__init__.py

@@ -85,11 +85,32 @@ def handle_api_error(error):
 
 def resource(*urls, **kwargs):
   def wrapper(api_resource):
+    if not api_resource:
+      return None
+
     api.add_resource(api_resource, *urls, **kwargs)
     return api_resource
   return wrapper
 
 
+def show_if(value):
+  def f(inner):
+    if not value:
+      return None
+
+    return inner
+  return f
+
+
+def hide_if(value):
+  def f(inner):
+    if value:
+      return None
+
+    return inner
+  return f
+
+
 def truthy_bool(param):
   return param not in {False, 'false', 'False', '0', 'FALSE', '', 'null'}
 
@@ -116,6 +137,7 @@ def method_metadata(func, name):
   return None
 
 
+
 nickname = partial(add_method_metadata, 'nickname')
 related_user_resource = partial(add_method_metadata, 'related_user_resource')
 internal_only = add_method_metadata('internal', True)