Input types

In addition to object types GraphQL also supports input types. While being similar to object types, they are better suited for input data as they limit the kind of types you can use for fields.

This is how the GraphQL spec defines the difference between object types and input types:

The GraphQL Object type (ObjectTypeDefinition)... is inappropriate for re‐use (as input), because Object types can contain fields that define arguments or contain references to interfaces and unions, neither of which is appropriate for use as an input argument. For this reason, input objects have a separate type in the system.

Defining input types

In Strawberry, you can define input types by using the @strawberry.input decorator, like this:

import strawberry

@strawberry.input
class Point2D:
    x: float
    y: float

input Point2D {
  x: Float!
  y: Float!
}

Then you can use input types as argument for your fields or mutations:

import strawberry

@strawberry.type
class Mutation:
    @strawberry.mutation
    def store_point(self, a: Point2D) -> bool:
        return True

If you want to include optional arguments, you need to provide them with a default. For example if we want to expand on the above example to allow optional labeling of our point we could do:

import strawberry
from typing import Optional

@strawberry.input
class Point2D:
    x: float
    y: float
    label: Optional[str] = None

type Point2D {
    x: Float!
    y: Float!
    label: String = null
}

Alternatively you can also use strawberry.UNSET instead of the None default value, which will make the field optional in the schema:

import strawberry
from typing import Optional

@strawberry.input
class Point2D:
    x: float
    y: float
    label: Optional[str] = strawberry.UNSET

type Point2D {
    x: Float!
    y: Float!
    label: String
}

API

@strawberry.input(name: str = None, description: str = None)

Creates an input type from a class definition.

• name: if set this will be the GraphQL name, otherwise the GraphQL will be generated by camel-casing the name of the class.
• description: this is the GraphQL description that will be returned when introspecting the schema or when navigating the schema using GraphiQL.