====== 第三十九章：Web应用项目 ======

===== 本章目标 =====

完成本章学习后，你将能够：
  * 设计Web应用架构
  * 实现用户认证
  * 集成数据库
  * 部署Web应用

===== 项目结构 =====

<code>
myapp/
├── app/
│   ├── __init__.py
│   ├── models.py
│   ├── views.py
│   ├── forms.py
│   └── templates/
├── config.py
├── requirements.txt
└── run.py
</code>

===== 用户认证 =====

<code python>
from flask import Flask, request, session, redirect, url_for
from werkzeug.security import generate_password_hash, check_password_hash

app = Flask(__name__)
app.secret_key = 'secret-key'

# 注册
@app.route('/register', methods=['POST'])
def register():
    username = request.form['username']
    password = generate_password_hash(request.form['password'])
    # 保存到数据库
    return redirect(url_for('login'))

# 登录
@app.route('/login', methods=['POST'])
def login():
    username = request.form['username']
    password = request.form['password']
    user = get_user(username)
    if user and check_password_hash(user.password, password):
        session['user_id'] = user.id
        return redirect(url_for('dashboard'))
    return 'Login failed'

# 登出
@app.route('/logout')
def logout():
    session.pop('user_id', None)
    return redirect(url_for('index'))
</code>

===== 数据库集成 =====

<code python>
from flask_sqlalchemy import SQLAlchemy

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///app.db'
db = SQLAlchemy(app)

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))
</code>

===== 本章实战 =====

1. 构建Todo应用
2. 构建博客系统
3. 构建电商网站

下一章：[[python_course:chapter40|第四十章：自动化脚本]]