flask

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField
from wtforms.validators import DataRequired, Length, Email, EqualTo
 
 
class (FlaskForm):
    username = StringField('用户名', [DataRequired('用户名必填！'), Length(min=6, max=20, message='用户名必须介于6-20字符！')])
    password = PasswordField('密码', [DataRequired('密码必填！'), Length(min=6, max=20, message='密码必须介于6-20字符！')])
    confirm = PasswordField('重复密码', [DataRequired('重复密码必填！'), EqualTo('password', message='两次密码输入不一致！')])
    email = StringField('邮箱', [DataRequired('邮箱必填！'), Email('邮箱格式不正确！')])

class RegView(MethodView):
    def get(self):
        form = UserRegisterForm(request.form)
        return render_template('register.html', form=form)
 
    def post(self):
        form = UserRegisterForm(request.form)
        if User.query.filter_by(username=form.username.data).first():
            flash("当前用户名已经注册！")
            return render_template('register.html', form=form)
        elif User.query.filter_by(email=form.email.data).first():
            flash("当前邮箱已经注册！")
            return render_template('register.html', form=form)
        else:
            form.validate_on_submit()
            user = User(
                form.username.data,
                form.password.data,
                form.email.data,
            )
            user.save()
            return redirect(url_for('.login'))

{% macro renden_field(field) %}
    {% if field.errors %}
        {% for error in field.errors %}
            <li style="font-size: medium">{{ error }}</li>
        {% endfor %}
    {% endif %}
{% endmacro %}
 
{% macro messages(get_flashed_messages) %}
    {% with messages = get_flashed_messages() %}
        {% if messages %}
            {% for message in messages %}
            <div class="alert alert-danger">
                <a href="#" class="close" data-dismiss="alert">×</a>
                {{ message }}
            </div>
            {% endfor %}
        {% endif %}
    {% endwith %}
{% endmacro %}