from typing import Dict, Generator

from litestar import Litestar, get
from litestar.di import Provide

STATE = {"result": None, "connection": "closed"}


def generator_function() -> Generator[str, None, None]:
    """Set the connection state to open and close it after the handler returns.

    If an error occurs, set `result` to `"error"`, else set it to `"OK"`.
    """
    try:
        STATE["connection"] = "open"
        yield "hello"
        STATE["result"] = "OK"
    except ValueError:
        STATE["result"] = "error"
    finally:
        STATE["connection"] = "closed"


@get("/{name:str}", dependencies={"message": Provide(generator_function)})
def index(name: str, message: str) -> Dict[str, str]:
    """If `name` is "John", return a message, otherwise raise an error."""
    if name == "John":
        return {name: message}
    raise ValueError()


app = Litestar(route_handlers=[index])