6---Flask-WTForms

Flask-WTF是简化了WTForms操作的一个第三方库。WTForms表单的两个主要功能是验证用户提交数据的合法性以及渲染模板。还有其它一些功能：CSRF保护，

文件上传等。安装方法：pip install flask-wtf

1.1.WTForms简单验证

from flask import Flask,request,render_template
from wtforms import Form,StringField
from wtforms.validators import Length,EqualTo

app = Flask(__name__)

class RegistForm(Form):
    username = StringField(validators=[Length(min=3,max=10,message=‘用户名必须在3到10位之间‘)])
    password = StringField(validators=[Length(min=6,max=10,message=‘密码必须6到10位之间‘)])
    password_repeat = StringField(validators=[Length(min=6,max=10),
                                              EqualTo("password",message=‘密码不一致‘)])

@app.route(‘/‘)
def hello_world():
    return ‘Hello World!‘

@app.route(‘/regist/‘,methods=[‘GET‘,‘POST‘])
def regist():
    if request.method == ‘GET‘:
        return render_template(‘regist.html‘)
    else:
        form = RegistForm(request.form)
        if form.validate():
            return ‘success‘
        else:
            print(form.errors)
            return ‘fail‘

if __name__ == ‘__main__‘:
    app.run()

1.2.WTForms常用验证器和自定义验证器

常用的验证器

Email:验证上传的数据是否为邮箱格式
EqualTo:两个字段是否相等（密码和重复密码）
InputRequired:原始数据的需要验证
Length:长度限制，有mix和max两个值
NumberRange:数字的区间，有mix和max两个值，如果在两个值之间则满足
Regexp:自定义正则表达式
URL:必须url格式
UUID:uuid格式

from wtforms import Form,StringField,IntegerField
from wtforms.validators import Length,EqualTo,Email,InputRequired,NumberRange
from wtforms.validators import Regexp,URL,ValidationError


class LoginForm(Form):
    email = StringField(validators=[Email(message=‘邮箱格式不正确‘)])
    username = StringField(validators=[InputRequired(message=‘这个字段必须要填‘)])
    age = IntegerField(validators=[NumberRange(min=18,max=100)])
    phone = StringField(validators=[Regexp(r‘1[38745]\d{9}‘)])
    homepage = StringField(validators=[URL()])
    captcha = StringField(validators=[Length(4,4)])

    # 自定义验证器
    def validate_captcha(self,field):
        if field.data != ‘1234‘:      #field.data：用户提交过来的数据
            raise ValidationError(‘验证码错误‘)          #如果验证失败，就抛出验证失败的异常

1.3.使用wtforms渲染模板

forms.py

class SettingsForm(Form):
    username = StringField(label="用户名：",validators=[InputRequired(message=‘这个字段必须要填‘)])
    age = IntegerField(‘年龄:‘,validators=[NumberRange(min=18, max=100)])
    remeber = BooleanField(‘记住我‘)
    tags = SelectField(‘标签‘,choices=[(1,‘python‘),(2,‘django‘)])

flask_wtforms_demo.py

@app.route(‘/settings/‘,methods=[‘GET‘,‘POST‘])
def settings():
    if request.method == ‘GET‘:
        form = SettingsForm()
        return render_template(‘settings.html‘,form=form)
    else:
        pass

settings.html

<form action="" method="post">
{#    括号里面可以添加样式#}
    <p>{{ form.username.label }} {{ form.username(class="") }}</p>
    <p>{{ form.age.label }} {{ form.age() }}</p>
    <p>{{ form.remeber.label }} {{ form.remeber() }}</p>
    <p>{{ form.tags.label }} {{ form.tags() }}</p>
    <p><input type="submit" value="提交"></p>
</form>

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