saronia 1.0.0

A lightweight, spec-driven builder for API clients and controllers.

saronia

A lightweight, spec-driven builder for API clients and controllers.

Installation

# Base installation
pip install saronia

# With rnet client
pip install saronia[rnet]

# With aiohttp client
pip install saronia[aiohttp]

Features

• Declarative API controller syntax
• Type-safe request/response handling with APIResult
• Support for multiple HTTP clients (rnet, aiohttp, or custom)
• Comprehensive error handling with StatusError decorator
• Support for path parameters, query params, headers, JSON, form data, and file uploads
• Built on top of msgspex for fast serialization and kungfu for Result types

Quick Start

import asyncio
from uuid import UUID

from kungfu import Error
from msgspex import Model
from saronia import API, APIResult, get, post

# With rnet
from rnet import Client
from saronia import RnetClient

# Or with aiohttp
# from aiohttp import ClientSession
# from saronia import AiohttpClient

cool_api = API.endpoint("/coolapi/v1")


class Book(Model):
    id: UUID
    name: str


class ValidationError(Model):
    message: str


class NotFoundError(Model):
    message: str


class CreateBookDTO(Model):
    id: UUID
    name: str


@cool_api("/books")
class BooksController:
    @get("/{book_id}")
    async def get_book_by_id(self, book_id: UUID) -> APIResult[Book, ValidationError | NotFoundError]:
        ...

    @post("/create", CreateBookDTO)
    async def create_book(self) -> APIResult[Book, ValidationError | NotFoundError]:
        ...


books = BooksController()


async def main() -> None:
    # Using rnet
    client = Client()
    cool_api.build(RnetClient(client, base_url="https://api.example.com"))

    # Or using aiohttp
    # async with ClientSession() as session:
    #     cool_api.build(AiohttpClient(session, base_url="https://api.example.com"))

    book = (await books.get_book_by_id(UUID("12345678-1234-5678-1234-567812345678"))).unwrap()
    print(f"Book: {book.name}")

    match await books.create_book(id=UUID("87654321-4321-8765-4321-876543218765"), name="New Book"):
        case Error(error):
            print(f"Error: {error}")


asyncio.run(main())

Error Handling

saronia provides comprehensive error handling following OpenAPI best practices:

from http import HTTPStatus
from saronia import StatusError

# Associate error types with HTTP status codes
class NotFoundError(Model, StatusError[HTTPStatus.NOT_FOUND]):
    message: str
    resource: str


class ValidationError(Model, StatusError[HTTPStatus.BAD_REQUEST, HTTPStatus.UNPROCESSABLE_ENTITY]):
    message: str
    details: dict[str, list[str]] | None = None

# Use in controller
@get("/{book_id}")
async def get_book(self, book_id: UUID) -> APIResult[Book, NotFoundError | ValidationError]:
    ...

# Handle errors
result = await books.get_book(book_id)

match result:
    case Error(api_error):
        print(f"Status: {api_error.status}")  # HTTPStatus enum
        print(f"Path: {api_error.path}")  # Request path
        print(f"Request ID: {api_error.request_id}")  # For tracing
        print(f"Is client error: {api_error.is_client_error}")  # 4xx
        print(f"Is server error: {api_error.is_server_error}")  # 5xx

        # Pattern match on specific error types
        match api_error.error:
            case NotFoundError(message=msg):
                print(f"Not found: {msg}")
            case ValidationError(message=msg, details=details):
                print(f"Validation failed: {msg}")
    case _:
        book = result.unwrap()
        print(f"Success: {book.name}")

Custom HTTP Client

You can implement your own HTTP client by inheriting from ABCClient:

from saronia.client.abc import ABCClient

class MyCustomClient(ABCClient):
    async def request(self, path, method, *, errors, response_type, ...):
        # Your implementation
        ...