What is the best practice to avoid code duplication on this code?

Question

I have the following code snippets for a Flask application:

import flask import Flask


app = Flask(__name__)


@app.route('/')
def index():

    # Some code...

    on_heroku = 'DYNO' in os.environ
    if on_heroku:
        # Do something
    else:
        # Do something

    return ("SUCCESS", 200)


def open_browser():
    on_heroku = 'DYNO' in os.environ
    if on_heroku:
        # Do something
    else:
        # Do something


if __name__ == "__main__":
    open_browser()
    app.run(debug=True)

I find the on_heroku = 'DYNO' in os.environ and the checking of the value of on_heroku are written twice in the code.

How can I improve the code (e.g., passing on_heroku as a parameter?) such that the program can still run without problems?

Answer 1

Make it a standalone function:

def check():
    on_heroku = 'DYNO' in os.environ
    if on_heroku:
        # Do something
    else:
        # Do something

def index():
    check()
def open_browser():
    check()

Also you could do the environ check within the if statement instead of assigning.

if 'DYNO' in os.environ:
    ...

Or even just assign it once globally at runtime:

on_heroku = 'DYNO' in os.environ

# then run the rest of the program