Sessions are no longer validated using the "/session/..." route. This
created a lot of problems due to buggy/unexpected behavior coming from
the Flask-Session dependency, which is (more or less) no longer
maintained.
Sessions are also no longer strictly server-side-only. The majority of
information that was being stored in user sessions was aesthetic only,
aside from the session specific key used to encrypt URLs. This key is
still unique per user, but is not (or shouldn't be) in anyone's threat
model to keep absolutely 100% private from everyone. Especially paranoid
users of Whoogle can easily modify the code to use a randomly generated
encryption key that is reset on session invalidation (and set
invalidation time to a short enough period for their liking).
Ultimately, this should result in much more stable sessions per client.
There shouldn't be decryption issues with element URLs or queries
during result page navigation.
This introduces a new approach to handling user sessions, which should
allow for users to set more reliable config settings on public instances.
Previously, when a user with cookies disabled would update their config,
this would modify the app's default config file, which would in turn
cause new users to inherit these settings when visiting the app for the
first time and cause users to inherit these settings when their current
session cookie expired (which was after 30 days by default I believe).
There was also some half-baked logic for determining on the backend
whether or not a user had cookies disabled, which lead to some issues
with out of control session file creation by Flask.
Now, when a user visits the site, their initial request is forwarded to
a session/<session id> endpoint, and during that subsequent request
their current session id is matched against the one found in the url. If
the ids match, the user has cookies enabled. If not, their original
request is modified with a 'cookies_disabled' query param that tells
Flask not to bother trying to set up a new session for that user, and
instead just use the app's fallback Fernet key for encryption and the
default config.
Since attempting to create a session for a user with cookies disabled
creates a new session file, there is now also a clean-up routine included
in the new session decorator, which will remove all sessions that don't
include a valid key in the dict. NOTE!!! This means that current user
sessions on public instances will be cleared once this update is merged
in. In the long run that's a good thing though, since this will allow session
mgmt to be a lot more reliable overall for users regardless of their cookie
preference.
Individual user sessions still use a unique Fernet key for encrypting queries,
but users with cookies disabled will use the default app key for encryption
and decryption.
Sessions are also now (semi)permanent and have a lifetime of 1 year.
Ben Busby