遇见Flask-Script

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) mark@ocarina:~/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) mark@ocarina:~/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) mark@ocarina:~/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) mark@ocarina:~/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) mark@ocarina:~/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..\t\n"
                   "输入y删除,n取消"):
        print('数据已删除...')
    else:
        print("就知道你不敢")
----------------------------------------
(flask_env) mark@ocarina:~/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) mark@ocarina:~/pycharmprojects/flask_one$ 

最后