遇见Flask-Script

Posted 2021-01-30 endurance9

Flask-Script是Flask的命令行扩展包，使用它可以通过命令行的形式操作Flask项目, 例如，可通过命令启动一个发版本的服务器,设置数据库和定时任务等。

类似Django的manage.py提供的命令，不同的是使用flask-script可以自定义更多的命令。

Install flask-script

一般在虚拟环境中安装

(flask_env) [email protected]:~/PycharmProjects/flask_one$ pip install flask-script
Collecting flask-script
  Downloading https://files.pythonhosted.org/packages/00/a4/cd587b2b19f043b65bf33ceda2f6e4e6cdbd0ce18d01a52b9559781b1da6/Flask-Script-2.0.6.tar.gz (43kB)
    100% |████████████████████████████████| 51kB 229kB/s 
Requirement already satisfied: Flask in /home/mark/.virtualenvs/flask_env/lib/python3.6/site-packages (from flask-script) (1.0.2)
Requirement already satisfied: Werkzeug>=0.14 in /home/mark/.virtualenvs/flask_env/lib/python3.6/site-packages (from Flask->flask-script) (0.14.1)
Requirement already satisfied: itsdangerous>=0.24 in /home/mark/.virtualenvs/flask_env/lib/python3.6/site-packages (from Flask->flask-script) (1.1.0)
Requirement already satisfied: click>=5.1 in /home/mark/.virtualenvs/flask_env/lib/python3.6/site-packages (from Flask->flask-script) (7.0)
Requirement already satisfied: Jinja2>=2.10 in /home/mark/.virtualenvs/flask_env/lib/python3.6/site-packages (from Flask->flask-script) (2.10)
Requirement already satisfied: MarkupSafe>=0.23 in /home/mark/.virtualenvs/flask_env/lib/python3.6/site-packages (from Jinja2>=2.10->Flask->flask-script) (1.1.0)
Building wheels for collected packages: flask-script
  Running setup.py bdist_wheel for flask-script ... done
  Stored in directory: /home/mark/.cache/pip/wheels/1c/17/70/4598e6dba4bec58c1b59552c6409272aea31978ab8159f11a1
Successfully built flask-script
Installing collected packages: flask-script
Successfully installed flask-script-2.0.6
(flask_env) [email protected]:~/PycharmProjects/flask_one$ 

使用flask-script

安装好了，不会用，怎么办？

在pycharm中点flask_script想进去看看，结果只进入了__init__.py中，看到如下内容：

class Manager(object):
    """
    Controller class for handling a set of commands.

    Typical usage::

        class Print(Command):

            def run(self):
                print "hello"

        app = Flask(__name__)

        manager = Manager(app)
        manager.add_command("print", Print())

        if __name__ == "__main__":
            manager.run()

    On command line::

        python manage.py print
        > hello

    :param app: Flask instance, or callable returning a Flask instance.
    :param with_default_commands: load commands **runserver** and **shell**
                                  by default.
    :param disable_argcomplete: disable automatic loading of argcomplete.

    """

使用方式一

导入flask_script中的Manager,Command

自定义的命令需要在Command的子类中重写run方法，在此方法中定义命令需要做什么事

实例化Manager(可以接收一个Flask对象作为参数)，调用Manager对象的add_command(‘命令‘, 自定义命令类实例)

from flask_script import Manager, Command
from app import app  # Flask对象


class TestCommand(Command):
    """
    测试命令
    """

    def run(self):  # 重写Command的run方法
        # 使用命令在控制台输出信息
        print("server run on xxx:80...")


manager = Manager(app) # 将flask_script与Flask联系起来
manager.add_command(‘test‘, TestCommand())

if __name__ == ‘__main__‘:
    manager.run()

在manage.py中执行manage.run()可以查看这个manage中包含的命令详情

/home/mark/.virtualenvs/flask_env/bin/python3.6 /home/mark/PycharmProjects/flask_one/manage.py
usage: manage.py [-?] {test,shell,runserver} ...

positional arguments:
  {test,shell,runserver}
    test                测试命令
    shell               Runs a Python shell inside Flask application context.
    runserver           Runs the Flask development server i.e. app.run()

optional arguments:
  -?, --help            show this help message and exit

Process finished with exit code 2

在命令行执行python manage.py test

(flask_env) [email protected]:~/PycharmProjects/flask_one$ python manage.py test
server run on xxx:80...

使用方式二

导入flask_script中的Manager,实例化之后使用@manager.command装饰器装饰一个函数，这样，这个函数名就成为一个命令，函数中的代码会在执行这个命令后执行。

from flask_script import Manager
from app import app

manager = Manager(app)

@manager.command
def music():
    """
    小妞，给爷唱一个
    """
    print("客官不可以，不可以摸我那里....")


if __name__ == ‘__main__‘:
    manager.run()

使用manager.run()查看

/home/mark/PycharmProjects/flask_one/manage.py
usage: manage.py [-?] {music,shell,runserver} ...

positional arguments:
  {music,shell,runserver}
    music               小妞，给爷唱一个
    shell               Runs a Python shell inside Flask application context.
    runserver           Runs the Flask development server i.e. app.run()

在命令行执行python manage.py music

(flask_env) [email protected]:~/PycharmProjects/flask_one$ python manage.py music
客官不可以，不可以摸我那里....

使用方式三

将命令定义在其他模块中，再引入到manage.py，将manage.py作为主命令模块。

from flask_script import Manager

# 不作为主命令模块，也就是说命令行是python manage.py xxx..
# 使用manage.py 而不是当前模块，这里的Manager()就不用传如Flask对象了
db_manager = Manager()

@db_manager.command
def migrate():
    """
    数据迁移命令
    """
    print("执行数据迁移...")

在manage.py中的引入方式：manger.add_command(‘prefix‘,manager对象)

from flask_script import Manager
from app import app
from db_manager import db_manager

manager = Manager(app)

# db是前缀 执行命令方式 python manage.py db migrate
manager.add_command(‘db‘, db_manager)

if __name__ == ‘__main__‘:
    manager.run()

执行结果：

(flask_env) [email protected]:~/PycharmProjects/flask_one$ python manage.py db migrate
执行数据迁移...

其他使用方式

可以使用manger.option()装饰器

命令函数可以接收参数

弹出确认操作：

@db_manager.command
def drop_data():
    if prompt_bool("你真的要删除这些数据吗？后果自负哦..	
"
                   "输入y删除,n取消"):
        print(‘数据已删除...‘)
    else:
        print("就知道你不敢")
----------------------------------------
(flask_env) [email protected]:~/PycharmProjects/flask_one$ python manage.py  db drop_data
你真的要删除这些数据吗？后果自负哦..    
输入y删除,n取消 [n]: n
就知道你不敢
(flask_env) [email protected]:~/PycharmProjects/flask_one$ 

最后

更详细的资料在官方文档。