Scalars¶
Graphene defines the following base Scalar Types:
graphene.String
graphene.Int
graphene.Float
graphene.Boolean
graphene.ID
Graphene also provides custom scalars for Dates, Times, and JSON:
graphene.types.datetime.DateTime
graphene.types.datetime.Time
graphene.types.json.JSONString
Custom scalars¶
You can create custom scalars for your schema. The following is an example for creating a DateTime scalar:
import datetime
from graphene.types import Scalar
from graphql.language import ast
class DateTime(Scalar):
'''DateTime Scalar Description'''
@staticmethod
def serialize(dt):
return dt.isoformat()
@staticmethod
def parse_literal(node):
if isinstance(node, ast.StringValue):
return datetime.datetime.strptime(
node.value, "%Y-%m-%dT%H:%M:%S.%f")
@staticmethod
def parse_value(value):
return datetime.datetime.strptime(value, "%Y-%m-%dT%H:%M:%S.%f")
Mounting Scalars¶
Scalars mounted in a ObjectType
, Interface
or Mutation
act as
Field
s.
class Person(graphene.ObjectType):
name = graphene.String()
# Is equivalent to:
class Person(graphene.ObjectType):
name = graphene.Field(graphene.String)
Note: when using the Field
constructor directly, pass the type and
not an instance.
Types mounted in a Field
act as Argument
s.
graphene.Field(graphene.String, to=graphene.String())
# Is equivalent to:
graphene.Field(graphene.String, to=graphene.Argument(graphene.String))