Merge branch 'patch-11'

Author: syrusakbary

graphene/relay/connection.py

@@ -5,6 +5,7 @@
 import six
 
 from graphql_relay import connection_from_list
+from promise import Promise
 
 from ..types import (AbstractType, Boolean, Enum, Int, Interface, List, NonNull, Scalar, String,
                      Union)
@@ -118,26 +119,34 @@ def type(self):
         return connection_type
 
     @classmethod
-    def connection_resolver(cls, resolver, connection, root, args, context, info):
-        resolved = resolver(root, args, context, info)
-
-        if isinstance(resolved, connection):
+    def resolve_connection(cls, connection_type, args, resolved):
+        if isinstance(resolved, connection_type):
             return resolved
 
         assert isinstance(resolved, Iterable), (
             'Resolved value from the connection field have to be iterable or instance of {}. '
             'Received "{}"'
-        ).format(connection, resolved)
+        ).format(connection_type, resolved)
         connection = connection_from_list(
             resolved,
             args,
-            connection_type=connection,
-            edge_type=connection.Edge,
+            connection_type=connection_type,
+            edge_type=connection_type.Edge,
             pageinfo_type=PageInfo
         )
         connection.iterable = resolved
         return connection
 
+    @classmethod
+    def connection_resolver(cls, resolver, connection_type, root, args, context, info):
+        resolved = resolver(root, args, context, info)
+
+        on_resolve = partial(cls.resolve_connection, connection_type, args)
+        if isinstance(resolved, Promise):
+            return resolved.then(on_resolve)
+
+        return on_resolve(resolved)
+
     def get_resolver(self, parent_resolver):
         resolver = super(IterableConnectionField, self).get_resolver(parent_resolver)
         return partial(self.connection_resolver, resolver, self.type)