Inputs and abstract types - FastQL

Input objects

from fastql import Input


@Input(description="Values accepted when creating a user.")
class CreateUserInput:
    name: str
    email: str

@Input follows the same class metadata contract as @Type, but its fields are compiled as GraphQL input fields and cannot have output resolvers.

Interfaces and unions

from fastql import Interface, Type, Union


@Interface
class Node:
    id: str


@Type(interfaces=[Node])
class User:
    id: str
    name: str


SearchResult = Union("SearchResult", types=[User])

Use interfaces when members guarantee shared fields. Use unions when members only share a possible result position.

Enums and scalars

@Enum maps Python enum members to GraphQL enum values. @Scalar or Scalar(...) defines custom serialization and parsing. Include non-root types explicitly in build_schema(types=[...]) when they are not reachable through a root field.