Force Flask url_for to use domain name (absolute url)

force_external_url_for.py

# In manage.py add
# Make sure you import: from flask import url_for
@app.context_processor
def override_url_for():
    return dict(url_for=external_url_for)


def external_url_for(endpoint, **values):
    # Force absolute url in assets
    if app.config.get('FORCE_EXTERNAL_URL'):
        values['_external'] = True
    return url_for(endpoint, **values)


# In config.py add
# Make sure you import: import os
FORCE_EXTERNAL_URL = \
        os.environ.get("FORCE_EXTERNAL_URL", "False") == "True"


# In your .env add
FORCE_EXTERNAL_URL="True"