from flask import Flask
from functools import wraps

app = Flask(__name__)

# Check that the request has the correct `bearer_token`.
def authenticate_admin(func):
    @wraps(func)
    def wrapped(*args, **kwargs):
        bearer_token = vault.get('secret/oauth')['bearer_token']
        expected = ("Bearer " + bearer_token)
        if expected != request.headers.get('Authorization'):
            return jsonify({'error': "Authorization token incorrect"}), 401

        return func(*args, **kwargs)
    return wrapped


# .... Define a bunch of routes (Elided) ....

for rule in app.url_map.iter_rules():
    # NEXT LINE IS PSEUDOCODE; IT IS WHAT I WANT TO ACHIEVE
    rule.fx = authenticate_admin(rule.fx)