4.2 表单类

from flask_wtf import Form
from wtforms import StringField, SubmitField
from wtforms.validators import Required, EqualTo
# 定义一个表单类
class NameForm(Form):
    name=StringField('what is you name', validators=[Required()])   # 创建一个type=text的input
    submit=SubmitField('Submit')                                    # 创建一个type=submit的input
    conPassword=StringField('confirm password', validators=[EqualTo('password', message='must match')])   # message好像必须有

WTForms支持的HTML标准字段

几个比较特殊的字段示意：

class NameForm(Form):
    radioSex=RadioField('性别', choices=[('1', '男人'), ('2', '女人')])
    selectHobby=SelectField('爱好', choices=[('3', '足球'), ('4', '篮球'), ('5', '乒乓')])
    # radioSex: 表单radio元素的name值
    # 第一个引号内: label值
    # choises=[]: 数组内'1'为value值

WTFroms验证函数

4.3 将表单渲染成HTML

{% extends "base.html" %} 
{% import "bootstrap/wtf.html" as wtf %} 
 
{% block title %}Flasky2b{% endblock %}
 
{% block page_content %} 
<div class="page-header"> 
    <h1>Hello, {% if name %}{{ name }}{% else %}Stranger{% endif %}!</h1> 
</div>
{#使用flask-bootstrap渲染表单#}
{{ wtf.quick_form(form) }} 
{% endblock %}

4.4 在视图函数中处理表单

# -*- coding:utf-8 -*-

# 把 str 编码由 ascii 改为 utf8
import sys
reload(sys)
sys.setdefaultencoding('utf8')
# 以下载入包
from flask import Flask, render_template
from flask_bootstrap import Bootstrap
from flask_moment import Moment              # 引入flask-moment
from datetime import datetime                # 引入datetime
from flask_wtf import Form
from wtforms import StringField,SubmitField,TextAreaField,IntegerField,BooleanField,RadioField,SelectField,FileField,PasswordField
from wtforms.validators import Required, email, EqualTo
app = Flask(__name__)
app.config['SECRET_KEY']="string hard"
bootstrap=Bootstrap(app)
moment=Moment(app)
# 定义一个表单类
class NameForm(Form):
    name=StringField('what is you name', validators=[Required()])        # 创建一个type="text"的input，文本传入label标签
    password=PasswordField('password')
    conPassword=StringField('confirm password', validators=[EqualTo('password', message='must match')])
    intro=TextAreaField('introduce yourself')
    email=StringField('input your email', validators=[email()])          # 必须是email格式
    integer=IntegerField('input an integer')
    booleanC=BooleanField('choose/let')
    radioSex=RadioField('性别', choices=[('1', '男人'), ('2', '女人')])   # 创建type="radio"单选框
    selectHobby=SelectField('爱好', choices=[('3', '足球'), ('4', '篮球'), ('5', '乒乓')]) #创建select下拉框
    submit=SubmitField('Submit')                                         # 创建一个type="submit"的input
    fileload=FileField('上传文件')
# 在视图函数中处理表单
@app.route('/', methods=['GET', 'POST'])
def hello_world():                      # 在视图函数中要定义name变量和form变量
    name=None
    intro=None
    form=NameForm()                     # 实例化一个NameForm()类
    if form.validate_on_submit():       # 表单验证成功，validate_on_submit()方法返回True
        name=form.name.data             #
        intro=form.intro.data
        form.name.data=''
    return render_template("form.html",
                           name=name,
                           intro=intro,
                           current_time=datetime.utcnow(),
                           form=form,
                           )

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

4.5 重定向和用户会话

不要让web程序将POST请求作为浏览器发送的最后一个请求;
使用重定向后，原先的name=form.name.data获取的数据就丢失了，所以要将数据存储在用户会话中，session

from flask import Flask, render_template, session, redirect, url_for 
 
@app.route('/', methods=['GET', 'POST']) 
def index(): 
    form = NameForm() 
    if form.validate_on_submit(): 

        session['name'] = form.name.data 
        return redirect(url_for('index'))   # 生成HTTP重定向响应，参数是重定向的URL
    return render_template('index.html', form=form, name=session.get('name'))
    # 使用.get('name')读取避免未找到键的异常情况

4.6 flash消息

在视图函数中使用flash()会生成一个消息，Flask把get_flashed_messages()函数开放给模板，用于模板中获取并渲染消息

{% block content %}
<div class='container'>
    {% for message in get_flashed_messages() %}
        <div class='alert alert-warning'>
            <button type='button' class='close' data-dismiss='alert'>×</button>
            {{ message }}
        </div>
    {% endfor %}
</div>
{% endblock %}

from flask import Flask,render_template,session,redirect,url_for,flash

@app.route('/',mrthod=['GET', 'POST'])
def index():
    form=NameForm()
    if form.validate_on_submit():
        old_name=session.get('name')
        if old_name is not None and old_name != form.name.data:
            flash('you changed your name!')
        session('name')=form.name.data
        return redirect(url_for('index'))
    return render_template('index.html', form=form, name=session.get('name'))