August 2018
Intermediate to advanced
230 pages
6h 42m
Chinese
Content preview from Flask Web开发：基于Python的Web应用开发实战（第2版）
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第 4 章
Web
表单
第
3
章编写的模板都是单向的，所有信息都从服务器流向用户。然而，对多数应用来说，
还需要沿相反的方向流动信息，把用户提供的数据交给服务器来处理。
使用
HTML
可以创建
Web
表单，供用户填写信息。表单数据由
Web
浏览器提交给服务
器，这一过程通常使用
POST
请求。第
2
章介绍的
Flask
请求对象包含客户端在请求中发送
的全部信息，对包含表单数据的
POST
请求来说，用户填写的信息通过
request.form
访问。
尽管
Flask
的请求对象提供的信息足以处理
Web
表单，但有些任务很单调，而且要重复操
作。比如，生成表单的
HTML
代码和验证提交的表单数据。
Flask-WTF
扩展可以把处理
Web
表单的过程变成一种愉悦的体验。这个扩展对独立的
WTForms
包进行了包装，方便集成到
Flask
应用中。
Flask-WTF
及其依赖可使用
pip
安装：
(venv) $
pip install flask-wtf
4.1
配置
与其他多数扩展不同，
Flask-WTF
无须在应用层初始化，但是它要求应用配置一个
密钥
。
密钥是一个由随机字符构成的唯一字符串，通过加密或签名以不同的方式提升应用的安全
性。
Flask
使用这个密钥保护用户会话，以防被篡改。每个应用的密钥应该不同，而且不
能让任何人知道。示例
4-1
展示如何在
Flask
应用中配置密钥。
示例
4-1
hello.py
：配置
Flask-WTF
app = Flask(__name__)
app.config['SECRET_KEY'] = 'hard to guess ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.