TypeError: argument 1 must be str, not None

[dubravat]

I am trying to run the example provided in https://github.com/deshaw/flask-kerberos/tree/master/example.

Here is the content of my 'example.py' file

from flask import Flask
from flask import render_template
from flask_kerberos import init_kerberos
from flask_kerberos import requires_authentication

from config import Config

app = Flask(__name__)
app.config.from_object(Config)

@app.route("/")
@requires_authentication
def index(user):
    return render_template('index.html', user=user)

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

and here is a 'config.py'

import os
import base64
from dotenv import load_dotenv

basedir = os.path.abspath(os.path.dirname(__file__))
load_dotenv(os.path.join(basedir, '.flaskenv'))

class Config(object):

# Setup Secret Key for Application
SECRET_KEY = os.environ.get('SECRET_KEY') or str(base64.b64encode('you-will-never-guess'.encode("utf-8")))

# Location of the keytab file
KRB5_KTNAME = "K000007.keytab"

When start the Flask via flask run I am getting the following error in CMD:

(venv) Server@Me:~/.../flask_kerberos_example$ flask run
 * Serving Flask app "example.py" (lazy loading)
 * Environment: development
 * Debug mode: on
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 603-674-916
a.b.c.d - - [23/Jun/2021 08:47:51] "GET / HTTP/1.1" 401 -
a.b.c.d - - [23/Jun/2021 08:47:51] "GET / HTTP/1.1" 500 -
Traceback (most recent call last):
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 2464, in __call__
    return self.wsgi_app(environ, start_response)
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 2450, in wsgi_app
    response = self.handle_exception(e)
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 1867, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/venv/lib/python3.7/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/venv/lib/python3.7/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/venv/lib/python3.7/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/venv/lib/python3.7/site-packages/flask_kerberos.py", line 106, in decorated
    rc = _gssapi_authenticate(token)
  File "/venv/lib/python3.7/site-packages/flask_kerberos.py", line 70, in _gssapi_authenticate
    rc, state = kerberos.authGSSServerInit(_SERVICE_NAME)
TypeError: argument 1 must be str, not None
a.b.c.d - - [23/Jun/2021 08:47:51] "GET /?__debugger__=yes&cmd=resource&f=style.css HTTP/1.1" 200 -
a.b.c.d - - [23/Jun/2021 08:47:51] "GET /?__debugger__=yes&cmd=resource&f=debugger.js HTTP/1.1" 200 -
a.b.c.d - - [23/Jun/2021 08:47:51] "GET /?__debugger__=yes&cmd=resource&f=jquery.js HTTP/1.1" 200 -
a.b.c.d - - [23/Jun/2021 08:47:51] "GET /?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 200 -
a.b.c.d - - [23/Jun/2021 08:47:51] "GET /?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 200 -

What can actually be a problem? How to resolve this?

[coolacid]

Try putting your init_kerberos(app) after app.config.from_object(Config)