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 9 章
用户角色
Web
应用中的用户并非都具有同等地位。在多数应用中，一小部分可信用户具有额外权
限，用于保障应用平稳运行。管理员就是最好的例子，但有时也需要介于管理员和普通用
户之间的角色，例如内容协管员。为此，要为所有用户分配一个
角色
。
在应用中实现角色有多种方法。具体采用何种实现方法取决于所需角色的数量和细分程
度。例如，简单的应用可能只需要两个角色，一个表示普通用户，一个表示管理员。对于
这种情况，在
User
模型中添加一个
is_administrator
布尔值字段可能就够了。复杂的应
用可能需要在普通用户和管理员之间再细分出多个不同等级的角色。有些应用甚至不能使
用分立的角色，赋予用户一系列独立的
权限
或许更合适。
本章介绍的用户角色实现方式结合了分立的角色和权限，赋予用户分立的角色，但是各个
角色都通过权限列表定义允许用户执行的操作。
9.1
角色在数据库中的表示
第
5
章为了演示一对多关系，创建了一个简单的 roles 表。示例
9-1
是改进后的 Role 模型。
示例
9-1
app/models.py
：角色数据库模型
class Role(db.Model):
__tablename__ = 'roles'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(64), unique=True)
default = db.Column(db.Boolean, default=False, index=True) ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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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.