flask_script
1. flask_script
doc: https://flask-script.readthedocs.io/en/latest/
The Flask-Script extension provides support for writing external scripts in Flask. This includes running a development server, a customised Python shell, scripts to set up your database, cronjobs, and other command-line tasks that belong outside the web application itself.
flask-script扩展提供了在flask上添加执行外围脚本的功能，包括运行开发服务器、定制命令、创建数据库、定时任务、或者其它命令行任务，上述内容均独立于flask应用本身。
Flask-Script works in a similar way to Flask itself. You define and add commands that can be called from the command line to a Manager instance:
换句话说它提供了一个包装，可以自定义命令，在命令行中调用Manager实例。
1.1. install/uninstall
pip install flask_script
pip uninstall flask_script
1.2. 添加命令
常用的有两种方式，装饰器，子类：
# 装饰器添加命令
@manager.command
def hello_1():
print('hello 1')
# 类方式添加命令
from flask_script import Command
class hello_2(Command):
"prints hello world"
def run(self):
print("hello 2")
manager.add_command('hello_2', hello_2)
其实还有一种option方式，用于复杂命令，有需要再看，这里不再赘述。
1.3. 案例
from app import create_app
import flask_migrate
from flask_script import Manager
app = create_app()
manager = Manager(app)
# 装饰器添加命令
@manager.command
def hello_1():
print('hello 1')
# 类方式添加命令
from flask_script import Command
class hello_2(Command):
"prints hello world"
def run(self):
print("hello 2")
manager.add_command('hello_2', hello_2)
if __name__ == '__main__':
manager.run()
结果释义：
执行命令
python manage.py hello_1 # hello_1 运行正常
python manage.py hello_2 # hello_2 运行正常
python manage.py hello_3 # manage.py: error: invalid choice: 运行异常，因为命令未声明