第九章：应用工厂和蓝图 —— 真正能长大的 Flask，都不会一直单文件

riderhub/
├── pyproject.toml
├── instance/
├── riderhub/
│   ├── __init__.py
│   ├── db.py
│   ├── auth.py
│   ├── missions.py
│   ├── templates/
│   │   ├── base.html
│   │   └── missions/
│   │       └── list.html
│   └── static/
│       └── app.css
└── tests/
    ├── conftest.py
    └── test_missions.py

from flask import Flask

def create_app(test_config=None):
    app = Flask(__name__, instance_relative_config=True)
    app.config.from_mapping(SECRET_KEY="dev")

    if test_config is not None:
        app.config.update(test_config)

    from . import db
    db.init_app(app)

    from .missions import bp as missions_bp
    app.register_blueprint(missions_bp)

    @app.get("/healthz")
    def healthz():
        return {"status": "ok"}

    return app

from flask import Blueprint, jsonify, request

bp = Blueprint("missions", __name__, url_prefix="/missions")

@bp.get("/")
def list_missions():
    status = request.args.get("status")
    return jsonify([
        {"id": 1, "name": "巡逻西门", "status": status or "ready"}
    ])

@bp.post("/")
def create_mission():
    data = request.get_json() or {}
    return {"id": 2, "name": data.get("name", "未命名任务")}, 201

Flask app   = 整个轻骑兵街区司令部
Blueprint   = 某个分街区的施工图与哨站注册表