datamodel-code-generator.md

name	description	url	github
datamodel-code-generator	Pydantic model and dataclasses.dataclass generator for easy conversion of JSON, OpenAPI, JSON Schema, GraphQL and YAML data sources.	https://koxudaxi.github.io/datamodel-code-generator/	koxudaxi/datamodel-code-generator

This code generator creates pydantic v1 and v2 model, dataclasses.dataclass, typing.TypedDict and msgspec.Struct from a graphql file and others.

$ pip install 'datamodel-code-generator[graphql]'

You can generate models from a local file. For the schema file

enum Episode {
  NEWHOPE
  EMPIRE
  JEDI
}

interface Character {
  id: ID!
  name: String!
  friends: [Character]
  appearsIn: [Episode]!
}

type Starship {
  id: ID!
  name: String!
  length: Float
}

type Human implements Character {
  id: ID!
  name: String!
  friends: [Character]
  appearsIn: [Episode]!
  starships: [Starship]
  totalCredits: Int
}

type Droid implements Character {
  id: ID!
  name: String!
  friends: [Character]
  appearsIn: [Episode]!
  primaryFunction: String
}

we can running

$ datamodel-codegen --input schema.graphql --input-file-type graphql --output model.py

# generated by datamodel-codegen:
#   filename:  schema.graphql
#   timestamp: 2023-11-27T07:48:49+00:00

from __future__ import annotations

from enum import Enum
from typing import List, Optional, TypeAlias

from pydantic import BaseModel, Field
from typing_extensions import Literal

Boolean: TypeAlias = bool
"""
The `Boolean` scalar type represents `true` or `false`.
"""


Float: TypeAlias = float
"""
The `Float` scalar type represents signed double-precision fractional values as specified by [IEEE 754](https://en.wikipedia.org/wiki/IEEE_floating_point).
"""


ID: TypeAlias = str
"""
The `ID` scalar type represents a unique identifier, often used to refetch an object or as key for a cache. The ID type appears in a JSON response as a String; however, it is not intended to be human-readable. When expected as an input type, any string (such as `"4"`) or integer (such as `4`) input value will be accepted as an ID.
"""


Int: TypeAlias = int
"""
The `Int` scalar type represents non-fractional signed whole numeric values. Int can represent values between -(2^31) and 2^31 - 1.
"""


String: TypeAlias = str
"""
The `String` scalar type represents textual data, represented as UTF-8 character sequences. The String type is most often used by GraphQL to represent free-form human-readable text.
"""


class Episode(Enum):
    EMPIRE = 'EMPIRE'
    JEDI = 'JEDI'
    NEWHOPE = 'NEWHOPE'


class Character(BaseModel):
    appearsIn: List[Optional[Episode]]
    friends: Optional[List[Optional[Character]]] = Field(default_factory=list)
    id: ID
    name: String
    typename__: Optional[Literal['Character']] = Field('Character', alias='__typename')


class Droid(Character):
    appearsIn: List[Optional[Episode]]
    friends: Optional[List[Optional[Character]]] = Field(default_factory=list)
    id: ID
    name: String
    primaryFunction: Optional[String] = None
    typename__: Optional[Literal['Droid']] = Field('Droid', alias='__typename')


class Human(Character):
    appearsIn: List[Optional[Episode]]
    friends: Optional[List[Optional[Character]]] = Field(default_factory=list)
    id: ID
    name: String
    starships: Optional[List[Optional[Starship]]] = Field(default_factory=list)
    totalCredits: Optional[Int] = None
    typename__: Optional[Literal['Human']] = Field('Human', alias='__typename')


class Starship(BaseModel):
    id: ID
    length: Optional[Float] = None
    name: String
    typename__: Optional[Literal['Starship']] = Field('Starship', alias='__typename')