Flask sqlalchemy check whether object in db.session and ready for commit

Question

I have objects which are newly created. I would like to know how can check whether current session has that object or not?

Something like this:

user = User(...)
....
db.session.add(user)
...
if db.session.has_object(user):
    <process further>

Is something like this possible?

Also, I would like to create after_request for my flask instance so that instead of bothering about commit, it will allow me to only check whether the db.session is ready for commit or not. If it is then execute db.session.commit().

Something like this:

@app.after_request
def after_request(response):
    if db.session.is_ready():
        db.session.commit()

Answer 1

You can inspect the object to see it's current state. If it's been added to the session, but not yet flushed to the database, it's going to have a pending status, for example:

from sqlalchemy import inspect

u = User(name='Alice')
inspection = inspect(u)
inspection.pending  # False

db.session.add(u)
inspection.pending # True

db.session.commit()
inspection.pending # False

There's a little intro to the object states in the docs.