Start function on run with Flask

Question

I have a flask app

@app.route("/hello")
def generater():
     return "hello world"

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

My application runs fine, but i would like to know how I could make a request to http://127.0.0.1:5000/hello when I compile my code

When i execute the command python hello.py the first thing that would happen is that it would go to localhost:port/hello and it would return hello world without me having to go to a webpage and type localhost/hello — rabiaasif, Nov 23 '18 at 18:09

score 8 · Accepted Answer · answered Nov 23 '18 at 19:06

8

You can use webbrowser to automatically open http://localhost:5000 in a web browser when running your flask app:

import webbrowser
...

if __name__ == '__main__':
    webbrowser.open('http://localhost:5000')
    app.run()

answered Nov 23 '18 at 19:06

Edgar Ramírez Mondragón

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this is exactly what I was looking for just need to try it on the server now! thank you – rabiaasif Nov 26 '18 at 22:29
This opens a browser, but if you dont want to keep it open? Just wget? – jaromrax Oct 06 '21 at 18:41

Charles Landau · Answer 2 · 2018-11-23T18:21:32.857

3

There are a lot of ways you could do this. You could just open up your browser to that location. You could try @jimtodd's answer and then cURL the endpoint from another terminal window.

To do it in the code, which I guess is what you want, Flask offers you some helper methods. For example there is: http://flask.pocoo.org/docs/1.0/api/#flask.Flask.before_first_request

You can use it like this:

def foo():
    pass

app.before_first_request(foo)

In the case where you want to run a script strictly on run, not just before the first request, this solution is good: Run code after flask application has started -- I guess you would use this for cold-start problems as well.

edited Nov 23 '18 at 18:21

answered Nov 23 '18 at 17:13

Charles Landau

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1

I dont want this to happen before I make a request, when I run python hello.py i want it to run foo without having to open a browser and make a request – rabiaasif Nov 23 '18 at 18:14
Edited my response to address this – Charles Landau Nov 23 '18 at 18:20
It is not effectively a right answer..This performs right before 1st request. Not after start. Any idea? – jaromrax Oct 06 '21 at 18:41

score -1 · Answer 3 · answered Nov 23 '18 at 17:07

-1

You can do this from command prompt:

set FLASK_APP=hello.py
python -m flask run

The you will see.... Running on http://127.0.0.1:5000

Now you can check the output in your browser.

answered Nov 23 '18 at 17:07

Jim Todd

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Start function on run with Flask

3 Answers3