spec2sdk 1.0.202502110942

Generate Pydantic models and API client code from OpenAPI 3.x specifications

Usage

From command line

• Local specification spec2sdk --schema-path path/to/api.yml --output-dir path/to/output-dir/
• Remove specification spec2sdk --schema-url https://example.com/path/to/api.yml --output-dir path/to/output-dir/

From the code

from pathlib import Path
from spec2sdk.main import generate

# Local specification
generate(schema_url=Path("path/to/api.yml").absolute().as_uri(), output_dir=Path("path/to/output-dir/"))

# Remove specification
generate(schema_url="https://example.com/path/to/api.yml", output_dir=Path("path/to/output-dir/"))

Open API specification requirements

Operation ID

operationId must be specified for each endpoint to generate meaningful method names. It must be unique among all operations described in the API.

Input

paths:
  /health:
    get:
      operationId: healthCheck
      responses:
        '200':
          description: Successful response

Output

class APIClient:
    def health_check(self) -> None:
        ...

Inline schemas

Inline schemas should be annotated with the schema name in the x-schema-name field that doesn't overlap with the existing schema names in the specification.

Input

paths:
  /me:
    get:
      operationId: getMe
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                x-schema-name: User
                type: object
                properties:
                  name:
                    type: string
                  email:
                    type: string

Output

class User(Model):
    name: str | None = Field(default=None)
    email: str | None = Field(default=None)

Enum variable names

Variable names for enums can be specified by the x-enum-varnames field.

Input

components: 
  schemas:
    Direction:
      x-enum-varnames: [ NORTH, SOUTH, WEST, EAST ]
      type: string
      enum: [ N, S, W, E ]

Output

from enum import StrEnum

class Direction(StrEnum):
    NORTH = "N"
    SOUTH = "S"
    WEST = "W"
    EAST = "E"

Custom types

Register Python converters and renderers to implement custom types.

Input

components: 
  schemas: 
    User:
      type: object
      properties:
        name:
          type: string
        email:
          type: string
          format: email

from pathlib import Path
from typing import Sequence

from spec2sdk.openapi.entities import DataType, StringDataType
from spec2sdk.models.converters import converters, convert_common_fields
from spec2sdk.models.entities import PythonType
from spec2sdk.models.imports import Import
from spec2sdk.main import generate


class EmailType(PythonType):
    @property
    def type_hint(self) -> str:
        return self.name or "EmailStr"

    @property
    def imports(self) -> Sequence[Import]:
        return (
            Import(name="EmailStr", package="pydantic"),
        )

    def render(self) -> str:
        return f"type {self.name} = EmailStr" if self.name else ""


def is_email_format(data_type: DataType) -> bool:
    return isinstance(data_type, StringDataType) and data_type.format == "email"


@converters.register(predicate=is_email_format)
def convert_email_field(data_type: StringDataType) -> EmailType:
    return EmailType(**convert_common_fields(data_type))


if __name__ == "__main__":
    generate(schema_url=Path("api.yml").absolute().as_uri(), output_dir=Path("output"))

Output

from pydantic import EmailStr, Field

class User(Model):
    name: str | None = Field(default=None)
    email: EmailStr | None = Field(default=None)

Writing HTTP client

HTTP client should conform to the HTTPClientProtocol which can be found in the generated api_client.py. Below is an example of the HTTP client implemented using httpx to handle HTTP requests.

from http import HTTPMethod, HTTPStatus
from typing import Any, Mapping
from urllib.parse import urlencode

import httpx
from httpx._types import AuthTypes, TimeoutTypes


class HTTPClient:
    def __init__(self, *, base_url: str, auth: AuthTypes | None = None, timeout: TimeoutTypes | None = None, **kwargs):
        self._http_client = httpx.Client(auth=auth, base_url=base_url, timeout=timeout, **kwargs)

    def build_url(self, path: str, query: Mapping[str, Any] | None = None) -> str:
        if query is None:
            return path

        return f"{path}?{urlencode(query, doseq=True)}"

    def send_request(
        self,
        method: HTTPMethod,
        url: str,
        accept: str | None = None,
        content_type: str | None = None,
        content: bytes | None = None,
        expected_status_code: HTTPStatus = HTTPStatus.OK,
    ) -> bytes | None:
        response = self._http_client.request(
            method=method,
            url=url,
            content=content,
            headers=content_type and {"Content-Type": content_type},
        )

        if response.status_code != expected_status_code:
            raise Exception(
                f"Unexpected status code for {method} {url}: {response.status_code}.",
            )

        if (accept is not None) and (accept not in (response_content_type := response.headers.get("Content-Type", ""))):
            raise Exception(f"Expected {accept}, got {response_content_type}.")

        return response.content