Question

For example, this code:

from flask import session

@app.route('/is_logged_in/')
def is_logged_in():
  return 'user' in session

It runs fine for me when running Flask’s development server, but it throws a 500 error with any webserver setup (FastCGI, uWSGI, etc.) on any server (Apache, nginx, Lighttpd).

Anybody know why?

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My actual code is on GitHub, if it matters.

It works flawlessly when running with Flask’s internal server, but I can’t get any session variables to work with a production webserver: https://github.com/Blender3D/Webminal/blob/master/server.py

Answer 1

I finally tried Tornado, thinking it would help with my problems (it’s written in Python, after all).

Lo and behold, a readable traceback:

RuntimeError: the session is unavailable because no secret key was set.
Set the secret_key on the application to something unique and secret.

Looks like I just forgot to add a secret key to sign sessions with:

app.secret_key = 'why would I tell you my secret key?'