Flask WTForm验证

from flask import Flask, render_template, redirect, url_for
from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, SubmitField
from wtforms.validators import DataRequired, Length

app = Flask(__name__)
app.config['SECRET_KEY'] = 'your_secret_key'

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

@app.route('/register', methods=['GET', 'POST'])
def register():
    form = RegistrationForm()
    if form.validate_on_submit():
        # 处理表单数据
        return redirect(url_for('success'))
    return render_template('register.html', form=form)

@app.route('/success')
def success():
    return 'Registration successful!'

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

<!-- register.html -->
<form method="POST">
    {{ form.hidden_tag() }}
    <p>
        {{ form.username.label }}<br>
        {{ form.username(size=32) }}<br>
        {% for error in form.username.errors %}
        <span style="color: red;">[{{ error }}]</span>
        {% endfor %}
    </p>
    <p>
        {{ form.password.label }}<br>
        {{ form.password(size=32) }}<br>
        {% for error in form.password.errors %}
        <span style="color: red;">[{{ error }}]</span>
        {% endfor %}
    </p>
    <p>{{ form.submit() }}</p>
</form>

app.config['SECRET_KEY'] = 'your_secret_key'