Add Email type

graphene/types/email.py

@@ -0,0 +1,36 @@
+from __future__ import absolute_import
+
+
+from graphql import Undefined
+from graphql.language.ast import StringValueNode
+import json
+from .scalars import Scalar
+
+
+class Email(Scalar):
+    """
+    Allows use of a JSON String for input / output from the GraphQL schema.
+
+    Use of this type is *not recommended* as you lose the benefits of having a defined, static
+    schema (one of the key benefits of GraphQL).
+    """
+
+    @staticmethod
+    def serialize(dt):
+        return json.dumps(dt)
+
+    @staticmethod
+    def parse_literal(node, _variables=None):
+        # email_validator 
+        # https://pypi.org/project/email-validator/
+        # max_length=254 to be compliant with RFCs 3696 and 5321
+        if isinstance(node, StringValueNode):
+            try:
+                return json.loads(node.value)
+            except Exception as error:
+                raise ValueError(f"Badly formed JSONString: {str(error)}")
+        return Undefined
+
+    @staticmethod
+    def parse_value(value):
+        return json.loads(value)