GraphQL schema and resolvers
All the GraphQL part is handled by Ariadne, a schema-first GraphQL library allowing to write the GraphQL schema using Schema Definition Language (SDL) and bind resolvers to it with minimal code.
Using Ariadne with Turbulette is quite straightforward, all Turbulette does is to define base query, mutation and subscription types for you so you can extend them in the schema.
Refer to Ariadne documentation for more information.
Schema
Assuming that we already created our Turbulette project and have an application named vehicles inside, let's start with a simple example schema in the 📁 schema folder:
# graphql/schema.graphql
extend type Query {
cars: [Car]
}
# Types
type Car {
id: ID!
model: String!
brand: String!
maxSpeed: Float!
isElectric: Boolean!
}
The first thing to note is that we extended the Query type. Why? simply because Turbulette already defines it internally. If you forget to extend you would get an error like this:
TypeError: There can be only one type named 'Query'
The same goes for Mutation and Subscription types.
Resolvers
Now that we have some schema defined we have to write the resolver for the cars query.
Create a car.py in the resolver package:
# resolvers/car.py
from turbulette import query # ObjectType("Query")
cars = [
{
"id": "1234",
"model": "X",
"brand": "SuperCars",
"maxSpeed": 235,
"isElectric": True
},
{
"id": "4321",
"model": "tank",
"brand": "SolidCar",
"maxSpeed": 145,
"isElectric": False
}
]
@query.field("cars")
async def cars_resolver(obj, info):
return cars
The important part here is @query.field("cars"): this is how ariadne knows that the cars_resolver function is the resolver of the cars query.
Info
As you see, we imported query from turbulette because the QueryType() object is already
defined by Turbulette, hence the need to extend the Query type in the schema.