Updating sqlalchemy orm instance in flask session

Question

In my flask app, I store an instance of a user object in the session

session["user"] = user #Where user is an object

I found out that when updating the object stored in the session directly and commit, the changes are not reflected in the database.

However, I found that when updating the database object directly, the changes are reflected in the database while the session object is unchanged.

If I try a method like

user.username = username
user.password = password
db.commit() #I called my database session 'db', probably not a good idea but not the point
session["user"] = user

it throws:

sqlalchemy.orm.exc.DetachedInstanceError: Instance is not bound to a Session; attribute refresh operation cannot proceed

What could be a possible solution to update the database correctly and reflect the changes to the flask session? Thanks in advance.

Are you using the flask-login extension or just plain flask? — kellymandem
– kellymandem, Commented Oct 8, 2019 at 10:40
I'm using plain flask and session in this case is the dictionary for flask-session not the database session — Natanael Tan
– Natanael Tan, Commented Oct 8, 2019 at 10:46

pnv · Accepted Answer · 2019-10-08 10:54:38Z

3

Try setting {'expire_on_commit': False} like,

db = SQLAlchemy(app, session_options={

    'expire_on_commit': False

})

edited Oct 8, 2019 at 10:54

answered Oct 8, 2019 at 10:45

pnv

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1 Comment

kellymandem Over a year ago

you are missing an equals sign here session_options{. It should be session_options = {

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