7.3 用户注册与登录

#### 7.3.1 用户注册

创建用户注册表单和视图：

Python复制

```python
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import DataRequired, Length

class RegistrationForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired(), Length(min=4, max=20)])
    password = PasswordField('Password', validators=[DataRequired(), Length(min=6, max=35)])
    submit = SubmitField('Register')

@app.route('/register', methods=['GET', 'POST'])
def register():
    form = RegistrationForm()
    if form.validate_on_submit():
        # 注册用户逻辑
        return redirect(url_for('login'))
    return render_template('register.html', form=form)
```

#### 7.3.2 用户登录

创建用户登录表单和视图：

Python复制

```python
class LoginForm(FlaskForm):
    username = StringField('Username', validators=[DataRequired(), Length(min=4, max=20)])
    password = PasswordField('Password', validators=[DataRequired(), Length(min=6, max=35)])
    submit = SubmitField('Login')

@app.route('/login', methods=['GET', 'POST'])
def login():
    form = LoginForm()
    if form.validate_on_submit():
        user = users.get(form.username.data)
        if user and user.password == form.password.data:
            login_user(user)
            return redirect(url_for('index'))
        flash('Invalid username or password')
    return render_template('login.html', form=form)
```

#### 7.3.3 用户登出

创建用户登出视图：

Python复制

```python
@app.route('/logout')
@login_required
def logout():
    logout_user()
    return redirect(url_for('index'))
```

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