在flask应用程序启动后运行代码 [英] Run code after flask application has started

问题描述

我的目标是在我的 Flask 应用程序启动后运行任意代码.这是我所拥有的:

My goal is to get arbitrary code to run after my Flask application is started. Here is what I've got:

def run():
    from webapp import app
    app.run(debug=True, use_reloader=False)

理想情况下，我可以这样做:

Ideally I would be able to just do this:

def run():
    from webapp import app
    app.run(debug=True, use_reloader=False)
    some_code()

但是代码不会继续超过 app.run()，所以 some_code() 永远不会运行.

But the code doesn't continue past app.run(), so some_code() never runs.

我目前正在研究的解决方案是在与 app.run() 不同的线程中运行 some_code()，创建一个 在第一个请求之前 设置这个的函数:

The solution I'm working on at the moment is to run some_code() in a separate thread from app.run(), create a before first request function that sets this:

app.is_running = True

然后使用 some_code() 向应用程序发出基本请求，以便运行第一个请求之前"代码.这是相当复杂的，将难以记录.我宁愿使用 Flask 中已经提供的 app.is_running 参数，或者使用 @app.after_server_start 装饰器，但据我所知，这两个都不存在.

Then get some_code() to shoot a basic request to app so that the 'before first request' code runs. This is fairly convoluted and going to be hard to document. I would rather use app.is_running parameter which already is provided in Flask, or use a @app.after_server_start decorator, but to my knowledge neither of those exists.

帮我改进这段代码?

Posthumous:每次想到这个问题，我都希望有一个 @app.after_server_start 装饰器存在.

Posthumous: Every time I think about this issue, it makes me wish that a @app.after_server_start decorator existed.

推荐答案

如果你需要在你的flask应用程序启动之后但严格在第一个请求之前执行一些代码，甚至不会被第一个请求的执行触发@app.before_first_request 可以处理，你应该使用 Flask_Script，正如 CESCO 所说，但你可以将类 Server 子类化并覆盖 __ call __ 方法，而不是用@manager.command 覆盖 runserver 命令:

If you need to execute some code after your flask application is started but strictly before the first request, not even be triggered by the execution of the first request as @app.before_first_request can handle, you should use Flask_Script, as CESCO said, but you could subclass the class Server and overwrite the __ call __ method, instead of overwriting the runserver command with @manager.command:

from flask import Flask
from flask_script import Manager, Server

def custom_call():
    #Your code
    pass

class CustomServer(Server):
    def __call__(self, app, *args, **kwargs):
        custom_call()
        #Hint: Here you could manipulate app
        return Server.__call__(self, app, *args, **kwargs)

app = Flask(__name__)
manager = Manager(app)

# Remeber to add the command to your Manager instance
manager.add_command('runserver', CustomServer())

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

这样您就不会覆盖 runserver 命令的默认选项.

This way you don't override default options of runserver command.

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