Added OmniScalar type

graphene/__init__.py

@@ -26,7 +26,7 @@ if not __SETUP__:
         InputField,
         Schema,
         Scalar,
-        String, ID, Int, Float, Boolean,
+        String, ID, Int, Float, Boolean, OmniScalar,
         List, NonNull,
         Enum,
         Argument,

graphene/types/__init__.py

@@ -4,7 +4,7 @@ from .objecttype import ObjectType
 from .abstracttype import AbstractType
 from .interface import Interface
 from .mutation import Mutation
-from .scalars import Scalar, String, ID, Int, Float, Boolean
+from .scalars import Scalar, String, ID, Int, Float, Boolean, OmniScalar
 from .schema import Schema
 from .structures import List, NonNull
 from .enum import Enum
@@ -32,6 +32,7 @@ __all__ = [
     'Int',
     'Float',
     'Boolean',
+    'OmniScalar',
     'List',
     'NonNull',
     'Argument',

graphene/types/scalars.py

@@ -9,7 +9,6 @@ from .unmountedtype import UnmountedType
 
 
 class ScalarTypeMeta(type):
-
     def __new__(cls, name, bases, attrs):
         # Also ensure initialization is only performed for subclasses of Model
         # (excluding Model class itself).
@@ -49,6 +48,7 @@ class Scalar(six.with_metaclass(ScalarTypeMeta, UnmountedType)):
         '''
         return cls
 
+
 # As per the GraphQL Spec, Integers are only treated as valid when a valid
 # 32-bit signed integer, providing the broadest support across platforms.
 #
@@ -164,3 +164,43 @@ class ID(Scalar):
     def parse_literal(ast):
         if isinstance(ast, (StringValue, IntValue)):
             return ast.value
+
+
+class OmniScalar(Scalar):
+    '''
+    The `OmniScalar` type represents any kind of scalar type.  For values
+    whose type is nondeterministic, an OmniScalar will parse and serialize it
+    appropriately.  Non-scalar types (lists and objects) are considered null.
+    '''
+
+    _scalar_type_map = {
+        str: String,
+        unicode: String,
+        bool: Boolean,
+        int: Int,
+        float: Float,
+    }
+
+    @staticmethod
+    def serialize(value):
+        scalar_type = OmniScalar._scalar_type_map.get(type(value))
+        if scalar_type:
+            return scalar_type.serialize(value)
+        else:
+            return None
+
+    @staticmethod
+    def parse_value(value):
+        scalar_type = OmniScalar._scalar_type_map.get(type(value))
+        if scalar_type:
+            return scalar_type.parse_value(value)
+        else:
+            return None
+
+    @staticmethod
+    def parse_literal(ast):
+        scalar_type = OmniScalar._scalar_type_map.get(type(ast))
+        if scalar_type:
+            return scalar_type.parse_literal(ast)
+        else:
+            return None

graphene/types/tests/test_scalars_serialization.py

@@ -1,4 +1,4 @@
-from ..scalars import Boolean, Float, Int, String
+from ..scalars import Boolean, Float, Int, String, OmniScalar
 
 
 def test_serializes_output_int():
@@ -48,3 +48,28 @@ def test_serializes_output_boolean():
     assert Boolean.serialize(0) is False
     assert Boolean.serialize(True) is True
     assert Boolean.serialize(False) is False
+
+
+def test_serializes_output_omniscalar():
+    # Int
+    assert OmniScalar.serialize(1) == 1
+    assert OmniScalar.serialize(0) == 0
+    assert OmniScalar.serialize(-1) == -1
+    # Float
+    assert OmniScalar.serialize(0.1) == 0.1
+    assert OmniScalar.serialize(1.1) == 1.1
+    assert OmniScalar.serialize(-1.1) == -1.1
+    # String
+    assert OmniScalar.serialize('string') == 'string'
+    assert OmniScalar.serialize(u'\U0001F601') == u'\U0001F601'
+    # Boolean
+    assert OmniScalar.serialize(False) is False
+    assert OmniScalar.serialize(True) is True
+    # Other
+    assert OmniScalar.serialize(None) is None
+    assert OmniScalar.serialize([]) is None
+    assert OmniScalar.serialize({}) is None
+    assert OmniScalar.serialize(object()) is None
+    assert OmniScalar.serialize(object) is None
+    assert OmniScalar.serialize(lambda _: '') is None
+