Flask系列09--Flask中WTForms插件,及自定义验证器

一.概述

　　django中的forms组件非常的方便,在flask中有WTForms的组件实现的也是类似的功能, 安装这个插件

二.简单使用

　　文档地址https://wtforms.readthedocs.io/en/latest/

　　简单写一个注册的form

# 注册表单
class RegForm(Form):
    username = simple.StringField(
        label='用户名',
        validators=[validators.DataRequired(message='用户名不能为空')]

    )

    password = simple.PasswordField(
        label='密码',
        validators=[
            validators.DataRequired(message='密码不能为空'),
            validators.Length(min=1, max=10, message='密码长度不正确'),
        ]
    )

    re_password = simple.PasswordField(
        label='确认密码',
        validators=[
            validators.EqualTo('password', message='密码不一致')
        ]
    )

    email = simple.StringField(
        label='邮箱',
        validators=[
            validators.Email(message='邮箱格式不正确')
        ]
    )

    hobby = core.SelectMultipleField(
        label='爱好',
        choices=[
            (1, '足球'),
            (2, '篮球'),
            (3, '网球'),
        ],

        default=[1, 3],  # 设置默认值,
        coerce=int

    )

    gender = core.SelectField(
        label='性别',
        choices=[
            (1, '男'),
            (2, '女')
        ],
        default=,
        coerce=int
    )

    sub = simple.SubmitField(
        label='提交',
        render_kw={'style': "color: red"},
    )

这里写了sub按钮,在前端文件中如果不想让标签显示出来比如

前端页面可以这样写

<form action="" method="post" novalidate>
    {% for field in form_obj %}
        {% if field.type == "SubmitField" %}
            <p>{{ field }}{{ field.errors.0 }}</p>
        {% else %}
            <p>{{ field.label }}{{ field }}{{ field.errors.0 }}</p>
        {% endif %}
    {% endfor %}
</form>

结果预览:

三 . 自定义验证器 validator

　　有两种写法,一种是类的,另外一种是写成函数

1.函数

class SignupForm(Form):
    age = IntegerField(u'Age')
    def validate_age(form, field):
        if field.data < 13:
            raise ValidationError("We're sorry, you must be 13 or older to register")

2. 类

# 自定义验证器,类 的写法
class pwd_validator():
    def __init__(self, message=None):
        self.message = message
    def __call__(self, form, field):
        pwd = field.data
        if pwd != '':
            raise ValidationError(self.message)

示例 登陆:

# 自定义验证器,类 的写法
class pwd_validator():
    def __init__(self, message=None):
        self.message = message
    def __call__(self, form, field):
        pwd = field.data
        if pwd != '':
            raise ValidationError(self.message)

class LoginForm(Form):
    username = simple.StringField(
        label='用户名',
        validators=[validators.DataRequired(message='用户名不能为空'), ]
    )
    # 自定义验证器, 函数的写法
    def validate_username(form, field):
        if field.data != 'tom':
            raise ValidationError('用户名错误')
    password = simple.PasswordField(
        label='密码',
        validators=[
            validators.DataRequired(message='密码不能为空'),
            validators.Length(min=1, max=10, message='密码长度不正确'),
            pwd_validator('密码必须是123'),

        ]
    )
    sub = simple.SubmitField(
        label='登陆',
        render_kw={'class': 'red'}
    )

cbv中运用

class Login(views.MethodView):
    def get(self):
        form_obj = LoginForm()
        return render_template("login.html", form_obj=form_obj)
    def post(self):
        dic = request.form.to_dict()
        username = dic.get('username')
        password = dic.get('password')
        # if username == 'tom' and password == '123':
        login_data = LoginForm(request.form)
        if login_data.validate():
            # print(login_data.data)
            session['user'] = dic['username']
            s = session.get('user')
            return '登陆成功 session是{}'.format(s)
        else:

            return render_template('login.html', form_obj=login_data)