Flask Api Development

# Application Factory and Configuration

## Application Factory and Configuration

```python
# config.py
import os

class Config:
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    JSON_SORT_KEYS = False

class DevelopmentConfig(Config):
    DEBUG = True
    TESTING = False
    SQLALCHEMY_DATABASE_URI = 'sqlite:///app.db'

class ProductionConfig(Config):
    DEBUG = False
    TESTING = False
    SQLALCHEMY_DATABASE_URI = os.getenv('DATABASE_URL')
    JWT_SECRET_KEY = os.getenv('JWT_SECRET_KEY')

class TestingConfig(Config):
    TESTING = True
    SQLALCHEMY_DATABASE_URI = 'sqlite:///:memory:'

# factory.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_jwt_extended import JWTManager

def create_app(config_name='development'):
    app = Flask(__name__)

    if config_name == 'production':
        from config import ProductionConfig
        app.config.from_object(ProductionConfig)
    else:
        from config import DevelopmentConfig
        app.config.from_object(DevelopmentConfig)

    db = SQLAlchemy(app)
    jwt = JWTManager(app)

    # Register blueprints
    from routes.auth import auth_bp
    from routes.users import users_bp
    app.register_blueprint(auth_bp)
    app.register_blueprint(users_bp)

    return app
```


# Authentication and JWT

## Authentication and JWT

```python
# auth.py
from flask import request, jsonify
from flask_jwt_extended import create_access_token, jwt_required, get_jwt_identity
from functools import wraps
from models import User, db

def authenticate_user(email, password):
    user = User.query.filter_by(email=email).first()
    if user and user.verify_password(password):
        return user
    return None

def login_required(f):
    @wraps(f)
    @jwt_required()
    def decorated_function(*args, **kwargs):
        identity = get_jwt_identity()
        user = User.query.get(identity)
        if not user or not user.is_active:
            return jsonify({'error': 'User not found or inactive'}), 401
        request.current_user = user
        return f(*args, **kwargs)
    return decorated_function

def admin_required(f):
    @wraps(f)
    @login_required
    def decorated_function(*args, **kwargs):
        if request.current_user.role != 'admin':
            return jsonify({'error': 'Admin access required'}), 403
        return f(*args, **kwargs)
    return decorated_function

# routes/auth.py
from flask import Blueprint, request, jsonify
from auth import authenticate_user, login_required
from models import User, db
from flask_jwt_extended import create_access_token

auth_bp = Blueprint('auth', __name__, url_prefix='/api/auth')

@auth_bp.route('/login', methods=['POST'])
def login():
    data = request.get_json()
    if not data or not data.get('email') or not data.get('password'):
        return jsonify({'error': 'Missing credentials'}), 400

    user = authenticate_user(data['email'], data['password'])
    if not user:
        return jsonify({'error': 'Invalid credentials'}), 401

    access_token = create_access_token(identity=str(user.id))
    return jsonify({
        'access_token': access_token,
        'user': user.to_dict()
    }), 200

@auth_bp.route('/register', methods=['POST'])
def register():
    data = request.get_json()
    if User.query.filter_by(email=data['email']).first():
        return jsonify({'error': 'Email already exists'}), 409

    user = User(email=data['email'], first_name=data.get('first_name'))
    user.set_password(data['password'])
    db.session.add(user)
    db.session.commit()

    return jsonify({'user': user.to_dict()}), 201

@auth_bp.route('/profile', methods=['GET'])
@login_required
def get_profile():
    return jsonify({'user': request.current_user.to_dict()}), 200
```


# Blueprints for Modular API Design

## Blueprints for Modular API Design

```python
# routes/users.py
from flask import Blueprint, request, jsonify
from auth import login_required, admin_required
from models import User, db
from sqlalchemy import or_

users_bp =