flasklet

A few nice things for Flask: typed flash messages, convention-based blueprint auto-discovery, route auto-importing, and helpers for rendering partials, blocks, and macros from Python.

Typed configuration

flasklet.config gives Flask apps a typed, environment-backed settings object instead of untyped app.config dict lookups.

from flasklet import config


class Settings(config.Config, prefix="BOXMINDER_"):
	base_url: str = config.from_env(default="/")
	flush_interval_seconds: int = config.from_env(default=60)


def create_app() -> Flask:
	app = Flask(__name__)
	settings = config.load(Settings)
	config.init_app(app, settings, flask_keys={"APPLICATION_ROOT": "base_url"})
	return app

A field's variable name defaults to the field name uppercased, prefixed with the class-level prefix (here BOXMINDER_BASE_URL and BOXMINDER_FLUSH_INTERVAL_SECONDS). Pass a name to from_env to override it. The prefix is inherited by subclasses. load(Settings, prefix=...) prepends a further prefix at load time.

load reads the environment when called (inside the app factory, not at import time) and converts values to the field's declared type: str, int, float, bool, Path, Optional[T], list[T], and NewType wrappers. A bool accepts only the exact strings true and false; a list is split on commas, with an empty variable meaning the empty list. A required field with a missing variable, or a value that cannot be converted, raises with the offending variable named.

Request-time access is typed through the generic read_config, passing the settings class:

config.read_config(Settings).base_url