Heroku Internal Server Error 500: 'NoneType' object has no attribute 'username'

Question

Trying to deploy my Flask app on Heroku when it returns the following error:

2019-11-29T09:07:28.456446+00:00 app[web.1]: File "/app/saltchat.py", line 55, in chatRoom
2019-11-29T09:07:28.456448+00:00 app[web.1]: onlineUsers.append(user.username)
2019-11-29T09:07:28.456454+00:00 app[web.1]: AttributeError: 'NoneType' object has no attribute 'username'
2019-11-29T09:07:28.458151+00:00 app[web.1]: 10.183.68.6 - - [29/Nov/2019:09:07:28 +0000] "GET /chat HTTP/1.1" 500 290 "https://salt-chat-v2.herokuapp.com/login" "Mozilla/5.0 (Windows NT 10
.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36"

When I deploy the app on my local machine it works just as intended and the problem is only encountered when routing through /chat:

@app.route('/chat', methods=['POST', 'GET'])
def chatRoom():
    username = session.get('username')
    user = Users.query.filter_by(username=username).first()
    if request.referrer is None:
        return render_template('login.html')
    else:
        onlineUsers.append(user.username)
        onlineUserAvatars.append(user.avatar)
        return render_template('chat.html')

Below is the model for the database that I used:

class Users(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(32), nullable=False)
    password = db.Column(db.String, nullable=False)
    avatar = db.Column(db.Integer)

Are you getting the `username` from session through this code ? `session.get('username')` — verisimilitude, Nov 29 '19 at 09:52
username = session.get('username') this is how you are getting username? — nithin, Nov 29 '19 at 09:55
Database I'm using is SQLite as for session.get('username') it works on my local machine just fine — CorvusRex, Nov 29 '19 at 10:17
Does this answer your question? [Why do I get AttributeError: 'NoneType' object has no attribute 'something'?](https://stackoverflow.com/questions/8949252/why-do-i-get-attributeerror-nonetype-object-has-no-attribute-something) — ChrisGPT was on strike, Nov 30 '19 at 00:14

score 0 · Answer 1 · answered Nov 29 '19 at 09:59

0

I think the problem is with your session user. Please modify your code as below:

@app.route('/chat', methods=['POST', 'GET'])
def chatRoom():
    username = session.get('username', '')
    try:  
        user = Users.query.filter_by(username=username).first()
    except:
        print("Something wrong")
    if request.referrer is None:
        return render_template('login.html')
    else:
        onlineUsers.append(user.username)
        onlineUserAvatars.append(user.avatar)
        return render_template('chat.html')

answered Nov 29 '19 at 09:59

Juhil Somaiya

873
7
20

Ok this is a weird one because I tried changing every session.get('username') with your code it works for once but after I log in as a new user it doesn't work for any other instances afterwards at least on Heroku (it works on local machine) – CorvusRex Nov 29 '19 at 10:58
how you are using/accessing database from heroku ? – Juhil Somaiya Nov 29 '19 at 11:00
SQLite I used db.create_all() to initialize the database – CorvusRex Nov 29 '19 at 11:25
@CorvusRex, this might not be your immediate problem, but [you can't use SQLite on Heroku](https://devcenter.heroku.com/articles/sqlite3). – ChrisGPT was on strike Nov 30 '19 at 01:48
I just noticed this problem and decided on using another database. Thanks @Chris – CorvusRex Dec 04 '19 at 11:03

Heroku Internal Server Error 500: 'NoneType' object has no attribute 'username'

1 Answers1