[FIXED] python flask before_first_request_funcs

Issue

In my python3 flask application I would like to execute a couple of recurring tasks before the first request. In order to achieve this, I want to make use of the@app.before_first_request_funcs.

Can anyone please give me an example usage of @app.before_first_request_funcs?

Here is my sample code:

import threading
import time

from flask import Flask

app = Flask(__name__)


def activate_job():
    def run_job():
        while True:
            print("recurring task")
            time.sleep(3)

    thread = threading.Thread(target=run_job())
    thread.start()


def activate_job2():
    def run_job2():
        while True:
            print("recurring task2")
            time.sleep(3)

    thread = threading.Thread(target=run_job2())
    thread.start()


@app.after_first_request(activate_job())
@app.before_first_request(activate_job2())
@app.route('/')
def home():
    return {"action": "This has done something"}


if __name__ == '__main__':
    print(app.before_first_request_funcs)
    app.run()

Solution

As per the documentation, you should use @app.before_first_request to do what you want.

from flask import Flask
app = Flask(__name__)
def some_func(some_arg):
    print('coucou')

# @app.before_first_request(some_func)
@app.route('/')
def home():
    return {"action" : "This has done something"}


if __name__ == '__main__':
    print(app.before_first_request_funcs)
    app.run()

You can see the behavior of the method before_first_request_funcs that is not a decorator by commenting and uncommenting the decorator before_first_request.

If it is commented, it'll print an empty list, and if you uncomment the line, it'll return a list of one element containing the function some_func object (for me, it was [<function some_func at 0x0000021393A0AD90>]).

Answered By - IMCoins