• 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..	
    "
                       "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

    更详细的资料在官方文档。

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  • 原文地址:https://www.cnblogs.com/endurance9/p/10192075.html
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