Added Dynamic type (resolved in runtime)

graphene/__init__.py

@@ -9,7 +9,8 @@ from .types import (
     String, ID, Int, Float, Boolean,
     List, NonNull,
     Enum,
-    Argument
+    Argument,
+    Dynamic
 )
 from .utils.resolve_only_args import resolve_only_args
 
@@ -30,4 +31,5 @@ __all__ = [
     'List',
     'NonNull',
     'Argument',
+    'Dynamic',
     'resolve_only_args']

graphene/types/__init__.py

@@ -8,6 +8,7 @@ from .enum import Enum
 from .field import Field
 from .inputfield import InputField
 from .argument import Argument
+from .dynamic import Dynamic
 from .inputobjecttype import InputObjectType
 
 __all__ = [

graphene/types/dynamic.py

@@ -0,0 +1,13 @@
+import inspect
+from ..utils.orderedtype import OrderedType
+
+
+class Dynamic(OrderedType):
+
+    def __init__(self, type, _creation_counter=None):
+        super(Dynamic, self).__init__(_creation_counter=_creation_counter)
+        assert inspect.isfunction(type)
+        self.type = type
+
+    def get_type(self):
+        return self.type()

graphene/types/tests/test_typemap.py

@@ -2,6 +2,8 @@ import pytest
 
 from ..objecttype import ObjectType
 from ..union import Union
+from ..field import Field
+from ..dynamic import Dynamic
 from ..enum import Enum
 from ..typemap import TypeMap
 from ..scalars import String
@@ -63,3 +65,18 @@ def test_objecttype():
     assert foo_field.args == {
         'bar': GraphQLArgument(GraphQLString, description='Argument description', default_value='x')
     }
+
+
+def test_dynamic_objecttype():
+    class MyObjectType(ObjectType):
+        '''Description'''
+        bar = Dynamic(lambda: Field(String))
+
+    typemap = TypeMap([MyObjectType])
+    assert 'MyObjectType' in typemap
+    assert MyObjectType._meta.fields.keys() == ['bar']
+    graphql_type = typemap['MyObjectType']
+
+    fields = graphql_type.get_fields()
+    assert fields.keys() == ['bar']
+    assert fields['bar'].type == GraphQLString

graphene/types/typemap.py

@@ -11,6 +11,7 @@ from .inputobjecttype import InputObjectType
 from .structures import List, NonNull
 from .enum import Enum
 from .scalars import Scalar, String, Boolean, Int, Float, ID
+from .dynamic import Dynamic
 
 from graphql import GraphQLString, GraphQLField, GraphQLList, GraphQLBoolean, GraphQLInt, GraphQLFloat, GraphQLID, GraphQLNonNull, GraphQLInputObjectField, GraphQLArgument
 from graphql.type import GraphQLEnumValue
@@ -189,6 +190,10 @@ class TypeMap(GraphQLTypeMap):
     def construct_fields_for_type(cls, map, type, is_input_type=False):
         fields = OrderedDict()
         for name, field in type._meta.fields.items():
+            if isinstance(field, Dynamic):
+                field = field.get_type()
+                if not field:
+                    continue
             map = cls.reducer(map, field.type)
             field_type = cls.get_field_type(map, field.type)
             if is_input_type:

graphene/types/utils.py

@@ -2,6 +2,7 @@ from collections import OrderedDict
 
 from .unmountedtype import UnmountedType
 from .field import Field
+from .dynamic import Dynamic
 from .inputfield import InputField
 
 
@@ -50,7 +51,7 @@ def unmounted_field_in_type(attname, unmounted_field, type):
 def get_fields_in_type(in_type, attrs):
     fields_with_names = []
     for attname, value in list(attrs.items()):
-        if isinstance(value, (Field, InputField)):
+        if isinstance(value, (Field, InputField, Dynamic)):
             fields_with_names.append(
                 (attname, value)
             )