Very simple and (almost) plug-and-play global CSRF filtering for Flask using the Double Submit technique outlined on OWASP at https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet#Double_Submit_Cookies.
Installation:
pip install dscsrf
How to use:
from dscsrf import Csrf
from flask import Flask
app = Flask(__name__)
csrf = Csrf(app)
and that's it!
For rendering the CSRF token in your application, under your form HTML use:
{{ csrf_token() }}