Improved lazy types support in Graphene

This commit also adds support for string types in Field, InputField, List and NonNull, where the string will be import. Usage like: Field("graphene.String")

graphene/types/field.py

@@ -6,6 +6,7 @@ from .argument import Argument, to_arguments
 from .mountedtype import MountedType
 from .structures import NonNull
 from .unmountedtype import UnmountedType
+from .utils import get_type
 
 
 base_type = type
@@ -60,9 +61,7 @@ class Field(MountedType):
 
     @property
     def type(self):
-        if inspect.isfunction(self._type) or type(self._type) is partial:
+        return get_type(self._type)
-            return self._type()
-        return self._type
 
     def get_resolver(self, parent_resolver):
         return self.resolver or parent_resolver

graphene/types/inputfield.py

@@ -1,5 +1,6 @@
 from .mountedtype import MountedType
 from .structures import NonNull
+from .utils import get_type
 
 
 class InputField(MountedType):
@@ -11,7 +12,11 @@ class InputField(MountedType):
         self.name = name
         if required:
             type = NonNull(type)
-        self.type = type
+        self._type = type
         self.deprecation_reason = deprecation_reason
         self.default_value = default_value
         self.description = description
+
+    @property
+    def type(self):
+        return get_type(self._type)

graphene/types/structures.py

@@ -1,4 +1,5 @@
 from .unmountedtype import UnmountedType
+from .utils import get_type
 
 
 class Structure(UnmountedType):
@@ -18,7 +19,11 @@ class Structure(UnmountedType):
                 cls_name,
                 of_type_name,
             ))
-        self.of_type = of_type
+        self._of_type = of_type
+
+    @property
+    def of_type(self):
+        return get_type(self._of_type)
 
     def get_type(self):
         '''

graphene/types/tests/test_field.py

@@ -1,9 +1,11 @@
 import pytest
+from functools import partial
 
 from ..argument import Argument
 from ..field import Field
 from ..structures import NonNull
 from ..scalars import String
+from .utils import MyLazyType
 
 
 class MyInstance(object):
@@ -66,6 +68,17 @@ def test_field_with_lazy_type():
     assert field.type == MyType
 
 
+def test_field_with_lazy_partial_type():
+    MyType = object()
+    field = Field(partial(lambda: MyType))
+    assert field.type == MyType
+
+
+def test_field_with_string_type():
+    field = Field("graphene.types.tests.utils.MyLazyType")
+    assert field.type == MyLazyType
+
+
 def test_field_not_source_and_resolver():
     MyType = object()
     with pytest.raises(Exception) as exc_info:

graphene/types/tests/test_inputfield.py

@@ -0,0 +1,30 @@
+import pytest
+from functools import partial
+
+from ..inputfield import InputField
+from ..structures import NonNull
+from .utils import MyLazyType
+
+
+def test_inputfield_required():
+    MyType = object()
+    field = InputField(MyType, required=True)
+    assert isinstance(field.type, NonNull)
+    assert field.type.of_type == MyType
+
+
+def test_inputfield_with_lazy_type():
+    MyType = object()
+    field = InputField(lambda: MyType)
+    assert field.type == MyType
+
+
+def test_inputfield_with_lazy_partial_type():
+    MyType = object()
+    field = InputField(partial(lambda: MyType))
+    assert field.type == MyType
+
+
+def test_inputfield_with_string_type():
+    field = InputField("graphene.types.tests.utils.MyLazyType")
+    assert field.type == MyLazyType

graphene/types/tests/test_structures.py

@@ -1,7 +1,9 @@
 import pytest
+from functools import partial
 
 from ..structures import List, NonNull
 from ..scalars import String
+from .utils import MyLazyType
 
 
 def test_list():
@@ -17,6 +19,23 @@ def test_list_with_unmounted_type():
     assert str(exc_info.value) == 'List could not have a mounted String() as inner type. Try with List(String).'
 
 
+def test_list_with_lazy_type():
+    MyType = object()
+    field = List(lambda: MyType)
+    assert field.of_type == MyType
+
+
+def test_list_with_lazy_partial_type():
+    MyType = object()
+    field = List(partial(lambda: MyType))
+    assert field.of_type == MyType
+
+
+def test_list_with_string_type():
+    field = List("graphene.types.tests.utils.MyLazyType")
+    assert field.of_type == MyLazyType
+
+
 def test_list_inherited_works_list():
     _list = List(List(String))
     assert isinstance(_list.of_type, List)
@@ -35,6 +54,23 @@ def test_nonnull():
     assert str(nonnull) == 'String!'
 
 
+def test_nonnull_with_lazy_type():
+    MyType = object()
+    field = NonNull(lambda: MyType)
+    assert field.of_type == MyType
+
+
+def test_nonnull_with_lazy_partial_type():
+    MyType = object()
+    field = NonNull(partial(lambda: MyType))
+    assert field.of_type == MyType
+
+
+def test_nonnull_with_string_type():
+    field = NonNull("graphene.types.tests.utils.MyLazyType")
+    assert field.of_type == MyLazyType
+
+
 def test_nonnull_inherited_works_list():
     _list = NonNull(List(String))
     assert isinstance(_list.of_type, List)

graphene/types/tests/utils.py

@@ -0,0 +1 @@
+MyLazyType = object()

graphene/types/typemap.py

@@ -283,6 +283,4 @@ class TypeMap(GraphQLTypeMap):
             return GraphQLList(self.get_field_type(map, type.of_type))
         if isinstance(type, NonNull):
             return GraphQLNonNull(self.get_field_type(map, type.of_type))
-        if inspect.isfunction(type):
-            type = type()
         return map.get(type._meta.name)

graphene/types/utils.py

@@ -1,5 +1,9 @@
+import inspect
 from collections import OrderedDict
+from functools import partial
+from six import string_types
 
+from ..utils.module_loading import import_string
 from .mountedtype import MountedType
 from .unmountedtype import UnmountedType
 
@@ -62,3 +66,11 @@ def yank_fields_from_attrs(attrs, _as=None, delete=True, sort=True):
     if sort:
         fields_with_names = sorted(fields_with_names, key=lambda f: f[1])
     return OrderedDict(fields_with_names)
+
+
+def get_type(_type):
+    if isinstance(_type, string_types):
+        return import_string(_type)
+    if inspect.isfunction(_type) or type(_type) is partial:
+        return _type()
+    return _type