flask

Flask Skill

Load when working on a Flask project. Use alongside all skills/common/ files.

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Stack

Layer	Library
Framework	Flask 3.x
ORM	SQLAlchemy 2.x + Flask-SQLAlchemy
Migrations	Flask-Migrate (Alembic)
Validation	marshmallow or pydantic v2
Auth	Flask-JWT-Extended
Settings	python-decouple / pydantic-settings
CLI	Click (built into Flask)

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Project Structure

myapp/
├── app/
│   ├── __init__.py           ← App factory: create_app()
│   ├── extensions.py         ← Flask extension instances
│   ├── config.py
│   ├── models/
│   ├── schemas/              ← Marshmallow schemas
│   ├── repositories/
│   ├── services/
│   ├── blueprints/
│   │   ├── users/
│   │   │   ├── __init__.py
│   │   │   ├── routes.py
│   │   │   └── tests/
│   │   └── auth/
│   │       ├── __init__.py
│   │       └── routes.py
│   └── errors.py             ← Error handlers
├── migrations/
├── tests/
├── .env.example
└── pyproject.toml

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App Factory

# app/__init__.py
from flask import Flask
from app.extensions import db, migrate, jwt
from app.config import Config
from app.errors import register_error_handlers
from app.blueprints.users import users_bp
from app.blueprints.auth import auth_bp

def create_app(config_class: type = Config) -> Flask:
    """Application factory."""
    app = Flask(__name__)
    app.config.from_object(config_class)

    # Initialize extensions
    db.init_app(app)
    migrate.init_app(app, db)
    jwt.init_app(app)

    # Register blueprints
    app.register_blueprint(users_bp, url_prefix="/api/v1/users")
    app.register_blueprint(auth_bp, url_prefix="/api/v1/auth")

    register_error_handlers(app)
    return app

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Extensions (Singleton Pattern)

# app/extensions.py
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from flask_jwt_extended import JWTManager

db = SQLAlchemy()
migrate = Migrate()
jwt = JWTManager()

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