Python Web开发：Flask框架应用案例

原创朱雀 2024-12-14 21:48 11阅读 0赞

Flask，一个轻量级的Web服务框架，常用于构建小型到中型规模的Web应用。下面我们将通过一些实际案例来学习如何使用Flask。

1. **Hello, Flask!**  
   这是最基础的Flask应用，用来验证Flask框架的基本功能。

```python
from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello, Flask!'

if __name__ == '__main__':
    app.run()
```

2. **RESTful API**  
   使用Flask构建一个简单的RESTful API，如创建、获取、更新和删除用户。

```python
from flask import Flask, jsonify, request

app = Flask(__name__)

users = [
    {"id": 1, "username": "user1"},
    {"id": 2, "username": "user2"},
]

@app.route('/users', methods=['GET'])
def get_users():
    return jsonify(users)

@app.route('/users', methods=['POST'])
def create_user():
    user_data = request.get_json()
    
    if user_data:
        users.append(user_data)
        return jsonify({"message": "User created successfully", "user": user_data}}), 201

@app.route('/users/<int:user_id>', methods=['GET'])
def get_user_by_id(user_id):
    for user in users:
        if user["id"] == user_id:
            return jsonify(user)
    
    return jsonify({"message": "User not found"})), 404

@app.route('/users/<int:user_id>', methods=['PUT'])
def update_user_by_id(user_id, updated_data):
    for idx, user in enumerate(users):
        if user["id"] == user_id:
            users[idx] = {**user, **updated_data}}
            return jsonify({"message": "User updated successfully", "user": updated_data}}), 200
       
    return jsonify({"message": "User not found"})), 404

@app.route('/users/<int:user_id>', methods=['DELETE'])
def delete_user_by_id(user_id):
    for idx, user in enumerate(users):
        if user["id"] == user_id:
            del users[idx]
            return jsonify({"message": "User deleted successfully", "user": {"id": user_id}}}), 200
       
    return jsonify({"message": "User not found"})), 404

if __name__ == '__main__':
    app.run(debug=True)
```

3. **Flask-Security**  
   使用Flask-Security扩展来实现用户登录、注册、密码找回等功能。

```python
from flask import Flask, render_template
from flask_security import Security, SQLAlchemyUserDatastore, login_required, current_user

app = Flask(__name__)

# Define database models for Flask-Security
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True))
    username = db.Column(db.String(80)), unique=True)
    password = db.Column(db.String(120)))

class Role(db.Model):
    id = db.Column(db.Integer, primary_key=True))
    name = db.Column(db.String(50)), unique=True)

# Define user datastore
user_datastore = SQLAlchemyUserDatastore(db, User, Role)

# Define security configuration
security = Security(app, user_datastore))

@app.route('/')
@login_required
def home():
    return render_template('home.html', current_user=current_user))

if __name__ == '__main__':
    app.run(debug=True)
```

通过以上案例，你应该对如何使用Flask构建Web应用有了更深入的理解。