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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56
｜
第
5
章
<p>Pleased to meet you!</p>
{% else %}
<p>Happy to see you again!</p>
{% endif %}
</div>
{{ wtf.quick_form(form) }}
{% endblock %}
如果你从
GitHub
上克隆了这个应用的
Git
仓库，那么可以执行
git checkout
5b
检出应用的这个版本。
5.10
集成
Python shell
每次启动
shell
会话都要导入数据库实例和模型，这真是份枯燥的工作。为了避免一直重复
导入，我们可以做些配置，让 flask shell 命令自动导入这些对象。
若想把对象添加到导入列表中，必须使用
app.shell_context_processor
装饰器创建并注册
一个
shell
上下文处理器
，如示例
5-7
所示。
示例
5-7
hello.py
：添加一个
shell
上下文
@app.shell_context_processor
def make_shell_context():
return dict(db=db, User=User, Role=Role)
这个
shell
上下文处理器函数返回一个字典，包含数据库实例和模型。除了默认导入的 app
之外，flask shell 命令将自动把这些对象导入
shell
。
$
flask shell
>>>
app
<Flask 'hello'>
>>>
db
<SQLAlchemy engine='sqlite:////home/flask/flasky/data.sqlite'> ...
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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.