flask mutable session (with flask-session RedisSessionInterface)

[decentral1se]

I am using the RedisSessionInterface of flask-session to implement my server side sessions. I have a test case that relies on mutating the session and I have read that this is possible from the Flask documentation.

Here's my test code (using pytest):

def test_code_already_used(app, client):
    uri = url_for("login.username")
    response = client.get(uri)  # stores the initial state in the session
    assert response.status_code == 302

    query = urlparse(response.location).query
    payload = dict(parse_qsl(query))
    state = payload['state']  # get key for session state

    with app.test_client() as context:
        transaction = context.session_transaction()
        with transaction as mutable_session:
            mutable_session[state] = {'exchanged': True}  # mutates the session

    # test code later fails becase the modification is not propagated

My application relies on seeing exchanged=True but this change is not there.

Any ideas!?

[davidism]

I can't reproduce your issue using the built-in session interface. If it is an issue with Flask-Session, you'll need to report it there.

from flask import Flask, session

app = Flask(__name__)
app.secret_key = 'test'

@app.route('/')
def index():
    return session.get('test', 'none')

with app.test_client() as c:
    with c.session_transaction() as s:
        s['test'] = 'test'

    r = c.get('/')
    print(r.data)  # b'test'

[decentral1se]

OK, thanks for taking a look @davidism!

[decentral1se]

I should note, the documentation says:

This works independently of the session backend used

Which, in this case, is not true (part of the reason I reported here). Should this be amended?

[davidism]

It does work independently. If it doesn't, it's either a problem with how you're using it or a problem with the backend.