graphql_schema.py

import graphene
import json, csv
from datetime import datetime
from flask import Flask
from flask_graphql import GraphQLView

app = Flask(__name__)

class User(graphene.ObjectType):
	id = graphene.ID()
	username=graphene.String()
	last_login = graphene.DateTime(required=False)


class Query(graphene.ObjectType):
	users = graphene.List(User, limit=graphene.Int())
	
	def resolve_users(self, info, limit):
		return [
			User(username='Alice', last_login=datetime.now()),
			User(username='Bob', last_login=datetime.now()),
			User(username='John', last_login=datetime.now()),
			User(username='Steven', last_login=datetime.now())
		][:limit]

class CreateUser(graphene.Mutation):

	class Arguments:
		username = graphene.String()
		
	user = graphene.Field(User)

	def mutate(self, info, username: str):
		if info.context.get('is_vip'):
			username = username.upper()
			csv_writer = csv.writer('data.csv', delimeter=',')
			csv_writer.writerow([username])

		user = User(username=username, last_login=datetime.now())
		return CreateUser(user=user)

class Mutation(graphene.ObjectType):
	create_user = CreateUser.Field(name='createUser')

schema = graphene.Schema(query=Query, mutation=Mutation)

app.add_url_rule(
	'/graphql',
	view_func=GraphQLView.as_view(
		'graphql',
		schema=schema,
		graphiql=True
	)
)

result = schema.execute(
		'''
			mutation createUser($username: String){
				createUser(username: $username) {
					user {
						username,
						lastLogin
					}
				}
			}
		''',
		variable_values = {'username': 'Bob'},
		context={'is_vip': False}
	)

items = dict(result.data.items())

print(json.dumps(items, indent=4))

if __name__ == '__main__':
	app.run()