system-pri/backend/app/__init__.py

import os

from flask import Flask
from flask_migrate import Migrate
from flask_cors import CORS

from .config import config
from .dependencies import db, ma
from .commands.startapp import startapp
from .utils import import_models
from .api import api_bp
from .errors import request_entity_too_large


def create_app(config_name: str = None) -> Flask:
    if config_name is None:
        config_name = os.environ.get("FLASK_ENV")

    app = Flask(__name__)
    app.config.from_object(config.get(config_name) or config.get("development"))

    if app.config['ENABLE_CORS']:
        CORS(app)

    db.init_app(app)
    ma.init_app(app)

    if config_name != "production":
        with app.app_context():
            import_models()

    Migrate(app, db)

    app.register_blueprint(api_bp)

    # register commands
    app.cli.add_command(startapp)

    # register errors
    app.register_error_handler(413, request_entity_too_large)

    return app